Angus, K, Thomas, P & Guerbois, J-P 2012, 'Synthesis and characterisation of cobaltite and ferrite spinels using thermogravimetric analysis and X-ray crystallography', Journal of Thermal Analysis and Calorimetry, vol. 108, no. 2, pp. 449-452.
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The synthesis for a series of ferrite (M IIFe 2O 4) and cobaltite (M IICo 2O 4) spinels was investigated where M II is Mg, Co, Ni, Cu or Zn. The ferrites were prepared at a calcination temperature of 800 °C; the cobaltites at 500 °C. TG-MS indicated that reduction of CoIII to CoII occurs at ca. 800 °C, hence, the lower calcination temperature. For both the ferrites and the cobaltites, the evolution of water and CO 2 during the calcination suggests the presence of both species in the precipitates. The observed mass losses indicated that the precursor basic carbonate precipitates for the cobaltite synthesis were predominantly carbonate, while the precursor basic carbonate precipitates for ferrite synthesis were predominantly hydroxide in character. XRD data showed successful synthesis of the ferrites with minimal contamination from the parent oxides, while the cobaltites were observed to be predominantly of the spinel structure. © Akadémiai Kiadó, Budapest, Hungary 2011.
Aoki, Y, Ravindrarajah, RS & Khabbaz, H 2012, 'Properties of pervious concrete containing fly ash', ROAD MATERIALS AND PAVEMENT DESIGN, vol. 13, no. 1, pp. 1-11.
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Pervious concrete isoneofthe most effective pavement materialsto addressanumber ofimportant environmental issues, such as recharging groundwater and reducing stormwater runoff. In this paper, the findings of an experimental investigation on properties of pervious concrete are reported and discussed. The amount of general purpose Portland cement has been reduced by introducing fly ash as a cementitious agent in pervious concrete samples. The properties of various pervious concrete samples including density, porosity, compressive strength, water permeability and drying shrinkage have been carefully measured. In addition, the relationships among these properties are explored. According to the results, high porosity samples indicated higher permeability, whereas their compressive strength was reduced. There was no significant difference between properties of pervious concrete samples containing fly ash and those samples comprising only cement as a cementitious agent. Hence, environmentally friendly pervious concrete with fly ash can be produced in lieu of conventional pervious concrete. © 2012 Taylor & Francis.
Aslani, F & Nejadi, S 2012, 'Bond Behavior of Reinforcement in Conventional and Self-Compacting Concrete', ADVANCES IN STRUCTURAL ENGINEERING, vol. 15, no. 12, pp. 2033-2051.
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Self-compacting concrete (SCC) can be placed under its own weight without compaction. In addition, it is cohesive enough to be handled without segregation and bleeding. Modification in the mix design of SCC can have a significant influence on the material's mechanical properties. Therefore, it is important to investigate whether all of the assumptions about conventional concrete (CC) design structures also valid for SCC construction. Bond behavior between concrete and reinforcement is a primary factor in the design of reinforced concrete structures. This study presents a bond strength model based on the experimental results from eight recent investigations of SCC and CC. In addition, the proposed model, code provisions, and empirical equations and experimental results from recent studies on the bond strength of SCC and CC are compared. The comparison is based on the measured bond between reinforcing steel and concrete utilizing the pullout test on the embedded bars at various heights in the mock-up structural elements to assess the top-bar effect on single bars in small prismatic specimens by conducting beam tests. The investigated varying parameters on bond strength are the: steel bar diameter, concrete compressive strength, concrete type, curing age of the concrete, and height of the embedded bar along the formwork.
Aslani, F & Nejadi, S 2012, 'Bond characteristics of reinforcing steel bars embedded in self-compacting concrete', Australian Journal of Structural Engineering, vol. 13, no. 3.
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Aslani, F & Nejadi, S 2012, 'Bond characteristics of steel fiber and deformed reinforcing steel bar embedded in steel fiber reinforced self-compacting concrete (SFRSCC)', Open Engineering, vol. 2, no. 3, pp. 445-470.
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AbstractSteel fiber reinforced self-compacting concrete (SFRSCC) is a relatively new composite material which congregates the benefits of the self-compacting concrete (SCC) technology with the profits derived from the fiber addition to a brittle cementitious matrix. Steel fibers improve many of the properties of SCC elements including tensile strength, ductility, toughness, energy absorption capacity, fracture toughness and cracking. Although the available research regarding the influence of steel fibers on the properties of SFRSCC is limited, this paper investigates the bond characteristics between steel fiber and SCC firstly. Based on the available experimental results, the current analytical steel fiber pullout model (Dubey 1999) is modified by considering the different SCC properties and different fiber types (smooth, hooked) and inclination. In order to take into account the effect of fiber inclination in the pullout model, apparent shear strengths (τ (app)) and slip coefficient (β) are incorporated to express the variation of pullout peak load and the augmentation of peak slip as the inclined angle increases. These variables are expressed as functions of the inclined angle (ϕ). Furthurmore, steel-concrete composite floors, reinforced concrete floors supported by columns or walls and floors on an elastic foundations belong to the category of structural elements in which the conventional steel reinforcement can be partially replaced by the use of steel fibers. When discussing deformation capacity of structural elements or civil engineering structures manufactured using SFRSCC, one must be able to describe thoroughly both the behavior of the concrete matrix reinforced with steel fibers and the interaction between this composite matrix and discrete steel reinforcement of the conventional type. However, even though the knowledge on bond behavior is essential for evaluating the overall behavior of structural components c...
Aslani, F & Nejadi, S 2012, 'Bond characteristics of steel fibre reinforced self-compacting concrete', CANADIAN JOURNAL OF CIVIL ENGINEERING, vol. 39, no. 7, pp. 834-848.
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Steel fibre reinforced self-compacting concrete (SFRSCC) is a relatively new composite material that combines the benefits of the self-compacting concrete (SCC) technology with the advantages derived from the fibre addition to a brittle cementitious matrix. Steel fibres improve many of the properties of SCC elements including tensile strength, ductility, toughness, energy absorption capacity, fracture toughness and cracking. Although the available research regarding the influence of steel fibres on the properties of SFRSCC is limited, this paper investigates the bond characteristics between steel fibre and SCC. Based on the available experimental results, the current analytical steel fibre pullout model is modified by considering the different SCC properties and different fibre types (smooth, hooked) and fibre inclination. To take into account the effect of fibre inclination in the pullout model, apparent shear strengths (τ (app)) and slip coefficient (β) are incorporated to express the variation of pullout peak load and the augmentation of peak slip as the inclined angle increases. These variables are expressed as functions of the inclined angle (φ).
Aslani, F & Nejadi, S 2012, 'Cyclic constitutive model for high-strength concrete confined by ultra-high-strength and normal-strength transverse reinforcements', Australian Journal of Structural Engineering, vol. 12, no. 2, pp. 159-172.
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In this paper, a cyclic constitutive model is developed for high-strength concrete (HSC) confined by ultra-high-strength and normal-strength transverse reinforcements (UHSTR and NSTR), with the intention of providing efficient modeling for the member and structural behaviour of HSC in seismic regions. The model for HSC subjected to monotonic and cyclic loading, comprises four components; an envelope curve (for monotonic and cyclic loading), an unloading curve, a reloading curve, and a tensile unloading curve. It explicitly accounts for the effects of concrete compressive strength, Volumetric ratio of transverse reinforcement, yield strength of ties, tie spacing, and tie pattern. Comparisons with test results showed that the proposed model provides a good fit to a wide range of experimental results. © Institution of Engineers, Australia 2012.
Aslani, F & Nejadi, S 2012, 'Mechanical properties of conventional and self-compacting concrete: An analytical study', CONSTRUCTION AND BUILDING MATERIALS, vol. 36, no. 1, pp. 330-347.
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Self-compacting concrete can be placed and compacted under its own weight with little or no compaction. It is cohesive enough to be handled without segregation or bleeding. It can be used to facilitate and ensure proper filling of complex and multipart formworks and consequently offers good structural performance in heavily reinforced structural members. Modification in the mix design of self-compacting concrete may significantly influence the material's mechanical properties. Therefore, it is vital to investigate whether all the assumed hypotheses about conventional concrete are also valid for self-compacting concrete structures. The present study includes: (a) evaluation and comparison of the current analytical models used for estimating the mechanical properties of self-compacting concrete and conventional concrete, and (b) proposing new models for the mechanical properties of both self-compacting and conventional concrete mixtures. The investigated mechanical properties are modulus of elasticity, tensile strength, and compressive stress-strain (σ-) curve. Extensive databases used for evaluating the analytical models include the measured modulus of elasticity of 110 self-compacting concrete mixtures and 32 conventional concrete mixtures, measured tensile strength of 81 self-compacting concrete mixtures and 26 conventional concrete mixtures, and compressive stress-strain curve of 28 self-compacting concrete mixtures and four conventional concrete mixtures. © 2012 Elsevier Ltd. All rights reserved.
Aslani, F & Nejadi, S 2012, 'Shrinkage behavior of self-compacting concrete', JOURNAL OF ZHEJIANG UNIVERSITY-SCIENCE A, vol. 13, no. 6, pp. 407-419.
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In the structures where long-term behavior should be monitored and controlled, creep and shrinkage effects have to be included precisely in the analysis and design procedures. Shrinkage varies with the constituent and mixture proportions, and depends on the curing conditions and the work environment as well. Self-compacting concrete (SCC) contains combinations of various components, such as aggregate, cement, superplasticizer, water-reducing agent and other ingredients which affect the properties of the SCC including shrinkage. Hence, the realistic prediction shrinkage strains of SCC are an important requirement of the design process for this type of concrete structures. This study reviews the accuracy of the conventional concrete (CC) shrinkage prediction models proposed by the international codes of practice, including CEB-FIP (1990), ACI 209R (1997), Eurocode 2 (2001), JSCE (2002), AASHTO (2004; 2007) and AS 3600 (2009). Also, SCC shrinkage prediction models proposed by Poppe and De Schutter (2005), Larson (2007), Cordoba (2007) and Khayat and Long (2010) are reviewed. Further, a new shrinkage prediction model based on the comprehensive analysis on both of the available models, i.e., the CC and the SCC is proposed. The predicted shrinkage strains are compared with the actual measured shrinkage strains in 165 mixtures of SCC and 21 mixtures of CC. © Zhejiang University and Springer-Verlag Berlin Heidelberg 2012.
Brennan, J & Martin, E 2012, 'Spatial proximity is more than just a distance measure', International Journal of Human-Computer Studies, vol. 70, no. 1, pp. 88-106.
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In order to design computer systems that are intuitive to use, the way humans reason about their âreal worldâ surroundings needs to be taken into consideration. Geographic Information Systems (GIS) focus on spatial reasoning. Over the last decades, many advances have been made in GIS interfaces and functionality; however the concept of proximity or nearness, which is essential in many forms of human reasoning, is still being addressed insufficiently. This paper provides a thorough and comprehensive synthesis of the disparate literature that pertains to the subject of proximity. It offers insights into why existing methods for reasoning with proximity work, or do not work, and analyses their strengths and weaknesses. Finally, the paper provides the derivation of new proximity measures, and their evaluation, backed by experiments and reflections. New measures are formally described in a unifying and compelling framework. This framework acknowledges that while distance is one factor that influences proximity perception, proximity is much more than just a distance measure.
Ding, GKC, Ge, JX & Phillips, P 2012, 'Cradle-to-Gate Analysis of Materials Used in Historic and Modern Housing in China', Advanced Materials Research, vol. 374-377, pp. 2029-2036.
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Climate change and energy efficiency are some of the most pressing issues facing China today. With its economic growth since the economic reforms in 1978 the government has struggled to contain environmental damage and social strife related to the economy’s rapid transformation. With the rapid growth in population and urbanization the demand for housings escalated and thus existing houses are under threat of being demolished to make way for new construction. However there was a strong debate that existing houses should be maintained and upgraded instead of demolishing for new development as improvements to energy and water efficiency of existing homes can significantly reduce greenhouse gas emissions and decrease utility bills. This paper aims at reviewing the importance of existing houses and their environmental significance in conservation as opposed to demolition. This paper presents and discusses the preliminary results for the first two stages of a research project undertaken at the University of Technology Sydney to investigate environmental performance of historic housings in Xiao He Zhi Jie in Hangzhou, China.
Erkmen, RE & Saleh, A 2012, 'Eccentricity effects in the finite element modelling of composite beams', ADVANCES IN ENGINEERING SOFTWARE, vol. 52, pp. 55-59.
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When modelling composite or built up beams using finite element software, analysts find it often convenient to connect two standard EulerâBernoulli beam elements at the nodes by using a rigid bar or use masterâslave type kinematic constraints to express the degrees-of-freedoms of one of the members in terms of the other. However, this type of modelling leads to eccentricity related numerical errors and special solutions that avoid eccentricity related issues may not be available for a design engineer due to the limitations of the software. In this study, a simple correction technique is introduced in the application of masterâslave type constraints. It is shown that the eccentricity related numerical errors in the stiffness matrix can be completely corrected by using extra fictitious elements and springs. The correction terms are obtained by using the exact homogenous solution of the composite beam problem as the interpolation functions which impose the zero-slip constraint between the two components in the point-wise sense. The effects of the eccentricity related errors are demonstrated in numerical examples.
Erkmen, RE, Bradford, MA & Crews, K 2012, 'Variational multiscale approach to enforce perfect bond in multiple-point constraint applications when forming composite beams', COMPUTATIONAL MECHANICS, vol. 49, no. 5, pp. 617-628.
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Composite laminates that consist of two or more layers find widespread applications in a variety of engineering structures. In the computational modelling of composite laminates, the layers can be stacked together and connected conveniently at the nodes by usingmultiple-point constraints (MPCs). However, this type of modelling leads to weakening of the kinematic constraint conditions imposed by the bond between the juxtaposed layers and as a consequence, MPCs application at the nodes produces behaviour that is softer than the perfectly bonded composite beam behaviour. The work herein shows that when kinematic conditions for composite action are weakly imposed in the variational form, they can be enforced in the point-wise sense by proper selection of the interpolation field or otherwise reinforced by using variational multiscale approach without modifying the kinematic model. The originality of the approach presented herein is in the interpretation of the MPCs application as the solution in a superfluously extended space because of the weakening in the kinematic constraints. It is shown that the perfect bond between the composite beam layers can be recovered by excluding the identified fine-scale effect from the solution of the multiple point constraint application. The convergence characteristic of the finite element formulation is also improved by using the variational multi-scale approach. It is also shown that the fine-scale effects can be represented by using extra fictitious elements and springs, which offers a direct correction technique in modelling of composite beams that is especially useful when access to the numerical procedure is limited.
Fatahi, B, Basack, S, Premananda, S & Khabbaz, H 2012, 'Settlement prediction and back analysis of Young's modulus and dilation angle of stone columns', Australian Journal of Civil Engineering, vol. 10, no. 1, pp. 67-80.
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Ground improvement using stone columns is one of the most suitable methods for deformation control of soft soils. The use of stone columns can improve the bearing capacity, reduce settlement, accelerate consolidation process and enhance slope stability as ivell as resistance to liquefaction. Settlement prediction of the ground influenced by the large stiffness difference between the columns and the surrounding soil and the induced arching is discussed in this paper. Plate load test is one of the common methods to be used for quality control of stone column reinforced ground. The test results can be used to back calculate some of the design parameters of the stone column. A finite element based procedure to estimate the Young's modulus and dilation angle o f stone column material using plate load test residts is proposed. The employed finite element model is axisymmetric and suitable for a cylindrical stone column. The field measurements after calibration have been in good agreement with numerical results for predicting deformations. The procedure developed in this study can be adopted by practicing engineers to estimate the Young's modulus and dilation angle of stone columns by conducting a plate load test. © Institution of Engineers Australia, 2012.
Fatahi, B, Khabbaz, H & Fatahi, B 2012, 'Mechanical characteristics of soft clay treated with fibre and cement', GEOSYNTHETICS INTERNATIONAL, vol. 19, no. 3, pp. 252-262.
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In this study, the influence of three types of fibre - polypropylene, recycled carpet and steel - on the mechanical properties of cement-treated clay is investigated. Cement-treated clay specimens were prepared with cement contents of 5%, 10% and 15% by weight of dry soil, and cured for 14 days. To investigate and understand the influence of different fibre types and contents, three different percentages of fibre content were adopted. The results of unconfined compression tests on 90 cylindrical samples of cement-treated clay with varied cement and fibre contents are analysed to discern the relationships between these parameters and the key mechanical properties, including unconfined compressive strength and stiffness of treated soil. Furthermore, indirect tension test results of a further 90 treated soil samples have been used to determine the influence of fibre and cement content on the tensile strength of the treated soil. The fibre reinforcement increases the peak compressive strength. The addition of fibres increases the residual strength and changes the brittle behaviour of the cement-treated clay to that of a more ductile material. The tensile strength of the cement-treated clay is increased by adding carpet and steel fibres, but small quantities of polypropylene fibres do not influence the tensile strength. © 2012 Thomas Telford Ltd.
Fatahi, B, Le, TM & Khabbaz, H 2012, 'Effects of initial stress state on performance of embankments on soft soils', Australian Geomechanics Journal, vol. 47, no. 3, pp. 77-88.
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Analysing the behaviour of soft soil under embankment loads is a challenging task for geotechnical engineers. This numerical study revisits the case study of an embankment constructed on Boston Blue Clay, considering the model incorporating the influence of soil creep on the ground lateral deformation and pore water pressure. Then a numerical parametric study is conducted to investigate the influence of the lateral earth pressure coefficient at rest (K0) calculated based on the different available correlations on the vertical and horizontal displacements, pore water pressures, and the factor of safety of the embankment. The results indicate that although the value of Ko influences the predicted horizontal and vertical displacements notably, it has minor effects on the predicted pore water pressures. The lateral earth pressure coefficient influences the long term stability of the embankment and thus the effects of the initial stress field on the stability of embankments should be taken into consideration, while assessing the performance of embankments constructed on soft soils. It is recommended to determine the in situ horizontal stresses using accurate methods such as self-boring pressuremeter to predict the behaviour of embankments on the soft ground precisely.
Fukumoto, T, Thomas, PS, Stuart, BH, Simon, P, Adam, G, Shimmon, R & Guerbois, J-P 2012, 'Estimation of the storage life of dimethylol urea using non-isothermal accelerated testing', JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, vol. 108, no. 2, pp. 439-443.
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Hamedanimojarrad, P, Adam, G, Ray, A, Thomas, P & Vessalas, K 2012, 'Development of shrinkage resistant microfibre-reinforced cement-based composites', Open Engineering, vol. 2, no. 2, pp. 289-295.
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AbstractDifferent shrinkage types may cause serious durability dilemma on restrained concrete parts due to crack formation and propagation. Several classes of fibres are used by concrete industry in order to reduce crack size and crack number. In previous studies, most of these fibre types were found to be effective in reducing the number and sizes of the cracks, but not in shrinkage strain reduction. This study deals with the influence of a newly introduced type of polyethylene fibre on drying shrinkage reduction. The novel fibre is a polyethylene microfibre in a new geometry, which is proved to reduce the amount of total shrinkage in mortars. This special hydrophobic polyethylene microfibre also reduces moisture loss of mortar samples. The experimental results on short and long-term drying shrinkage as well as on several other properties are reported. The hydrophobic polyethylene microfibre showed promising improvement in shrinkage reduction even at very low concentrations (0.1% of cement weight).
Hamedanimojarrad, P, Galea, N, Ray, AS, Adam, G, Vessalas, K & Thomas, P 2012, 'New mechanisms for drying shrinkage compensation in cementitious materials', Concrete in Australia, vol. 38, no. 3, pp. 33-38.
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There are several materials and methods which have been designed and used for reduction or compensation of drying shrinkage deformations in cementitious materials, in both industry and research . Typical strategies currently used in industry for overcoming drying shrinkage include introduction of expansive agents; use of shrinkage reducing admixtures (SRA) and fibres as components of mixtures; cement modification; and, taking advantage of internal curing (Kovler & Zhutovsky, 2006).
Hokmabadi, AS, Fakher, A & Fatahi, B 2012, 'Full scale lateral behaviour of monopiles in granular marine soils', MARINE STRUCTURES, vol. 29, no. 1, pp. 198-210.
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Monopiles are used in piers as mooring or berthing dolphins. This article reports the results of full-scale lateral loading tests on monopiles constructed as dolphins in the Pars Special Economic Energy Zone in southern Iran. The length and diameter of the monopiles were approximately 40 m and 2 m, respectively. Lateral loading tests of such large monopiles are not commonly undertaken, thus there is limited data available. This research developed a lateral analysis of piles computer code to examine analytical methods for pile analysis. Appropriate models were introduced resulting in accurate predictions in the analysis of lateral loaded piles. The results showed that traditional p-y curves and strain wedge models calculate larger pile head deflection in comparison to the field test data and therefore local calibration is essential. © 2012 Elsevier Ltd.
Hokmabadi, AS, Fatahi, B & Samali, B 2012, 'Recording inter-storey drifts of structures in time-history approach for seismic design of building frames', Australian Journal of Structural Engineering, vol. 13, no. 2, pp. 175-179.
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The growing trend in the application of direct displacement-based or performance-based design, lays more emphasis on the precise prediction of design parameters such as the inter-storey drift controlling the performance level of the structure. Practising engineers employ different methods to record the inter-storey drifts in time-history approach mainly based on the maximum lateral deformation of the structure. In this study, a 15-storey concrete moment resisting building is designed using time-history analysis. Then reliability and accuracy of each method in predicting the maximum inter-storey drifts under the influence of three earthquake records, namely 1995 Kobe, 1994 Northridge and 1940 El Centro earthquakes, are investigated. Results clearly indicate that to choose the most critical drift to evaluate the performance level of structures, the absolute maximum drift over time should be calculated. Other methods based on the maximum storey deflection may result in unconservative design.
Howes, JM, Stuart, BH, Thomas, PS, Raja, S & O'Brien, C 2012, 'An Investigation of Model Forensic Bone in Soil Environments Studied Using Infrared Spectroscopy', JOURNAL OF FORENSIC SCIENCES, vol. 57, no. 5, pp. 1161-1167.
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Infrared spectroscopy has been used to examine changes to bone chemistry as a result of soil burial. Pig carcasses were buried as part of a controlled field study, and pig bone was used in soil environments established in the laboratory. The variables of species type, bone pretreatment, soil type and pH, moisture content, temperature, and burial time were investigated. The crystallinity index (CI) and the organic and carbonate contents of the bones were monitored. The data revealed decreasing trends in the organic and carbonate contents and an increase in the CI of the bone with burial time. An acidic soil environment and soil type are the factors that have the most influence on bone chemistry as a result of burial. The study demonstrates the potential of infrared spectroscopy as a straightforward method of monitoring the changes associated with aging of bones in a variety of soil environments. © 2012 American Academy of Forensic Sciences.
Hu, H, Jiang, X, Wang, J & Li, Y 2012, 'Design, modeling, and controlling of a large-scale magnetorheological shock absorber under high impact load', JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES, vol. 23, no. 6, pp. 635-645.
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In this article, an MRD50 type of large-scale magnetorheological shock absorber was designed and manufactured in Smart Materials and Structures Laboratory of Nanjing University of Science and Technology. Upon providing a brief background on magnetorheological dampers, the detailed structure of this developed large-scale magnetorheological shock absorber was depicted. A suit of hardware-in-the-loop simulation platform under high impact load excitation was introduced for a weapon system. A series of tests were conducted to establish the dynamic behaviors of magnetorheological shock absorber under impact loads. The test results show that the inertia damping force should not be ignored like a common magnetorheological damper because of the large acceleration from the impact load. Based on the theory model and the experimental data, index parameters of magnetorheological fluid and other structural parameters in Herschel-Bulkley-Inertia model were identified by using the least square algorithm. In order to evaluate the controllability of large-scale magnetorheological shock absorber applied into high impact loads, three control algorithms, including on-off control, proportional-integral-derivative control, and fuzzy control algorithm, were used in tests to control the dynamic behavior of magnetorheological shock absorber, and some results of the controllability tests were exhibited in this article. In conclusion, the results indicated that the developed large-scale magnetorheological shock absorber was indeed able to effectively control the recoil dynamics. © The Author(s) 2012.
Huang, Q, Xu, YL, Li, JC, Su, ZQ & Liu, HJ 2012, 'Structural damage detection of controlled building structures using frequency response functions', Journal of Sound and Vibration, vol. 331, no. 15, pp. 3476-3492.
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If a building structure requires both a vibration control system and a health monitoring system, the integration of the two systems will be cost-effective and beneficial. One of the key problems of this integrated system is how to use control devices to enhance system identification and damage detection. This paper presents a new method for system identification and damage detection of controlled building structures equipped with semi-active friction dampers through model updating based on frequency response functions. The two states of the building are first created by adding a known stiffness using semi-active friction dampers. A scheme based on the frequency response functions of the two states of the building is then presented to identify stiffness parameters of structural members in consideration of structural connectivity and transformation information. By applying the proposed model updating scheme to the damaged building, a damage detection scheme is proposed based on the identified stiffness parameters of structural members of both the original and damaged buildings. The feasibility of the proposed schemes is finally demonstrated through a detailed numerical investigation in terms of an example building, in which the effects of measurement noise and excitation conditions are discussed. The numerical results clearly show that the proposed method can locate and quantify damage satisfactorily even though measurement noise is taken into consideration. © 2012 Elsevier Ltd. All rights reserved.
Indraratna, B, Nimbalkar, S & Rujikiatkamjorn, C 2012, 'Track Stabilisation with Geosynthetics and Geodrains, and Performance Verification through Field Monitoring and Numerical Modelling', International Journal of Railway Technology, vol. 1, no. 1, pp. 195-219.
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Khorsandnia, N, Valipour, HR & Crews, K 2012, 'Experimental and analytical investigation of short-term behaviour of LVL-concrete composite connections and beams', CONSTRUCTION AND BUILDING MATERIALS, vol. 37, no. 1, pp. 229-238.
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This paper reports the results of experimental push-out tests on three different types of timber-concrete composite (TCC) connections, including normal screw, SFS and bird-mouth. The load-slip diagrams obtained from lab tests are employed to calculate the slip modulus of the connections for serviceability, ultimate and near collapse cases based on Eurocode 5 recommendations. Additionally, four full-scale TCC beams with normal screw, SFS and bird-mouth are constructed and tested under four-point bending within the serviceability load range to verify the slip modulus of connections which derived from the push-out tests. Further, based on the experimental results and using nonlinear regression, an analytical model each one of the connections is derived which can be easily incorporated into nonlinear FE analyses of TCC beams. © 2012 Elsevier Ltd. All rights reserved.
Le, TM, Fatahi, B & Khabbaz, H 2012, 'Viscous Behaviour of Soft Clay and Inducing Factors', Geotechnical and Geological Engineering, vol. 30, no. 5, pp. 1069-1083.
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As a result of the scarcity of land for construction, a number of projects to construct man-made islands or to expand lands over soft grounds keeps increasing. Creep behaviour of soft ground has been considered as a challenging issue for engineers and researchers for many years. A number of studies have focused on the method to predict the creep deformation of the ground under a construction site. However, there is no unified theory to clearly explain the mechanism of soil creep deformation of soils. Results of the critical review in this paper indicate that the causes of soil creep can be categorised into five main groups, namely (a) the breakdown of the inter-particle bonds, (b) sliding between the soil particles, (c) water flow from micro-pores to macro-pores (d) the deformation due to the structural viscosity and (e) the deformation due to the jumping of bonds. This paper presents these mechanisms in details with an effort to recommend an enhanced explanation for the creep compression mechanisms of clays. © 2012 Springer Science+Business Media B.V.
Li, W, Xiao, J & Yuan, J 2012, 'Stress distribution characteristics of modeled recycled aggregate concrete under uniaxial compression', Tongji Daxue Xuebao/Journal of Tongji University, vol. 40, no. 6, pp. 906-913.
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Based on the mechanical properties of each material phase in recycled aggregate concrete (RAC), a two-dimensional modeled RAC was built, and the stress distribution characteristics of the modeled RAC under uniaxial compressive were obtained by meso-level numerical analysis. A parametric analysis was conducted to investigate the sensitivity of the stress distribution of the modeled RAC, which focused on different mechanical parameters of natural aggregate, interfacial transition zone (ITZ) and old hardened mortar. Results show that a concentration of tensile stress and shear stress produces at new and old interfacial transition zones between the natural aggregates. The higher elastic modulus of natural aggregates are, the higher the magnitude of stress concentration is, and the higher elastic modulus of the interfacial transition are, the lower the magnitude of stress concentration is. Whereas the effects of the elastic modulus of old hardened mortar on stress concentration are not evident.
Li, W, Xiao, J, Sun, Z & Shah, SP 2012, 'Failure processes of modeled recycled aggregate concrete under uniaxial compression', Cement and Concrete Composites, vol. 34, no. 10, pp. 1149-1158.
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In order to investigate the failure processes of Recycled Aggregate Concrete (RAC), cracking behavior of modeled RAC specimens under compressive loading was investigated using Digital Image Correlation (DIC). Strain and displacement contour maps were produced to analyze the cracks' initiation and propagation during loading. The testing results indicate that the discrepancy between the elastic moduli of coarse aggregates and mortar matrix significantly influences the mechanical properties and crack patterns of the modeled materials. It is found that the failure process is related to the relative strength of coarse aggregate and mortar matrix. For modeled RAC, the first bond cracks appear around both the old and new interfacial transition zones (ITZ), and then propagate into the old and new mortar matrix by connecting each other. The observation implies that the initiations and propagations of microcracks are different between RAC and Natural Aggregate Concrete (NAC). The findings in this investigation are useful to improve the mechanical properties of RAC by optimizing the mix proportion. © 2012 Elsevier Ltd. All rights reserved.
Li, W, Xiao, J, Sun, Z, Kawashima, S & Shah, SP 2012, 'Interfacial transition zones in recycled aggregate concrete with different mixing approaches', Construction and Building Materials, vol. 35, pp. 1045-1055.
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Interfacial Transition Zone (ITZ) is an important phase that influences the mechanical properties of Recycled Aggregate Concrete (RAC). This paper is devoted to an investigation of the effect of different mixing approaches on the properties of ITZs in RAC. Nanoindentation and Scanning Electron Microscopy (SEM) were implemented to characterize nanomechanical properties and microstructures of the old and new ITZs. The results indicate that the indentation modulus of ITZs have different distribution trends when using different mixing approaches. It reveals that the Two-Stage Mixing Approach (TSMA) can improve the nanomechanical properties of the new ITZ by reducing the volume fraction of voids and Calcium Hydroxide (CH). The SEM observation also indicates that an obviously denser and more homogeneous microstructure was achieved in the new ITZ prepared by TSMA compared to a Normal Mixing Approach (NMA). Correlating the nanoindentation and SEM results with the compressive strength, it can be concluded that TSMA has a beneficial influence on the mechanical properties of RAC by improving the properties of the new ITZ. © 2012 Elsevier Ltd. All rights reserved.
Li, Z, Wu, C, Olayiwola, JN, Hilaire, DS & Huang, JJ 2012, 'Telemedicine-based digital retinal imaging vs standard ophthalmologic evaluation for the assessment of diabetic retinopathy.', Conn Med, vol. 76, no. 2, pp. 85-90.
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OBJECTIVE: To study the cost benefit analysis of using a telemedicine-based digital retinal imaging evaluation compared to conventional ophthalmologic fundus examination of diabetic patients for diabetic retinopathy. METHODS: In this study, diabetic patients from Community Health Center, Inc. (CHCI), a large multi-site Federally Qualified Health Center) were evaluated by teleophthalmology using the Canon CR-1 nonmydriatic fundus camera. Digital images were acquired in the CHCI offices and saved on the EyePACS server network. The images were later evaluated by retinal specialists at the Yale Eye Center, Yale University Department of Ophthalmology and Visual Science. The costs for the standard of care ophthalmic examinations were calculated based on 2009 Medicaid reimbursement rates. The process of telemedicine-based diagnosis was based on a take-store-forward-visualize system. The cost of telemedicine-based digital retinal imaging examination included cost for devices, training, annual costs and a transportation fee. Current Medicaid reimbursement, transportation, and staff labor costs were used to calculate the conventional retinal examination cost as a comparison. RESULTS: Among the 611 patients digital retinal images screened in the first year of this program and for whom data are available, 166 (27.2%) cases of diabetic retinopathy were identified. Seventy-five (12.3%) patients screened positive with clinically significant disease and were referred for further ophthalmological evaluation and treatment. The primary direct cost of the telemedicine was $3.80, $15.00, $17.60, $1.50, and $2.50 per patient for medical assistant, ophthalmologist, capital cost (Equipment + Training), equipment maintenance, and transportation fee, respectively. The total cost in the telemedicine-based digital retinal imaging and evaluation was $40.40. The cost of conventional retinal examination was $8.70, $65.30, and $3.80 per patients for round-trip transportation, 2009 nat...
Macabuag, J, Guragain, R & Bhattacharya, S 2012, 'Seismic retrofitting of non-engineered masonry in rural Nepal', Proceedings of the Institution of Civil Engineers - Structures and Buildings, vol. 165, no. 6, pp. 273-286.
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One of the greatest causes of casualties in major earthquakes around the world is the collapse of non-engineered masonry buildings (those built without engineering input). Yet by definition non-engineered structures remain largely outside of the scope of modern engineering research, meaning that the majority of those at risk often remain so. A further barrier to realising research in this field is the significant social and economic challenge of implementation in low-income communities, where non-engineered housing is prevalent. This paper introduces a retrofitting technique aimed at preventing or prolonging the collapse of adobe (mud brick) houses under strong earthquakes. This technique uses common polypropylene packaging straps to form a mesh, which is then used to encase structural walls. The aim of this paper is to give an overview of the retrofitting technique's development and implementation. The key development stages of static, dynamic and numerical testing are presented, showing that the proposed technique effectively prevents brittle masonry collapse and the loss of debris. An implementation project is then discussed, involving a training programme for rural masons in Nepal, a public shake-table demonstration and the retrofit of a real house. The implementation project proved effective at reaching rural communities but highlighted that government subsidies are required to incentivise the safeguarding of homes among low-income communities.
Materin, MA, Bianciotto, CG, Wu, C & Shields, CL 2012, 'SECTOR LASER PHOTOCOAGULATION FOR THE PREVENTION OF MACULAR EDEMA AFTER PLAQUE RADIOTHERAPY FOR UVEAL MELANOMA', Retina, vol. 32, no. 8, pp. 1601-1607.
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Objective: To investigate the role of sector laser photocoagulation for prevention of macular edema after plaque radiotherapy for uveal melanoma. Methods: Noncomparative, pilot interventional case series. The main outcome measure was optical coherence tomography-evident macular edema. Results: A total of 29 patients had sector laser photocoagulation (sector panretinal photocoagulation) and sub-Tenon triamcinolone injection. The median tumor thickness and base was 3.3 mm and 10.0 mm. The median radiation dose and rate to the macula was 2,944 cGy and 31.0 cGy/hour. At the 12-month and 24-months follow-up, cystoid macular edema was found in 17% and 24% of the sector panretinal photocoagulation group. There were no major side effects registered. Conclusion: Sector panretinal photocoagulation in combination with sub-Tenon triamcinolone appears to show potential as a safe and beneficial intervention for the prevention of macular edema after plaque radiotherapy for uveal melanoma in this series.
Nabavi, SF, Nejadi, S & Samali, B 2012, 'Technical and Economical Assessment of the Corrosion Preventive Methods for Maritime Reinforced Concrete Structures', Applied Mechanics and Materials, vol. 193-194, pp. 1005-1009.
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Corrosion of embedded steel reinforcing in concrete structures is the predominant phenomenon of premature deterioration of structures exposed to marine environment. In this study, the technical advantages and disadvantages of the most commonly corrosion preventive methods are investigated and then cost analysis by comparing the Present Value of the methods is carried out for 40 years of life time. This investigation proved that the lower cost methods have not shown an acceptable performance in long term and those which have exhibited a good performance, have increased the lifetime cost of structure considerably.
Nimbalkar, S, Indraratna, B, Dash, SK & Christie, D 2012, 'Improved Performance of Railway Ballast under Impact Loads Using Shock Mats', Journal of Geotechnical and Geoenvironmental Engineering, vol. 138, no. 3, pp. 281-294.
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Samali, B, Dackermann, U & Li, J 2012, 'Location and Severity Identification of Notch-Type Damage in a Two-Storey Steel Framed Structure Utilising Frequency Response Functions and Artificial Neural Network', ADVANCES IN STRUCTURAL ENGINEERING, vol. 15, no. 5, pp. 743-757.
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This paper presents a vibration-based damage identification method that utilises damage fingerprints embedded in frequency response functions (FRFs) to identify location and severity of notch-type damage in a two-storey framed structure. The proposed method utilises artificial neural networks (ANNs) to map changes in FRFs to damage characteristics. To enhance damage fingerprints in FRF data, residual FRFs, which are differences in FRF data between the undamaged and the damaged structures, are used for ANN inputs. By adopting principal component analysis (PCA) techniques, the size of the residual FRF data is reduced in order to obtain suitable patterns for ANN inputs. A hierarchy of neural network ensembles is created to take advantage of individual characteristics of measurements from different locations. The method is applied to laboratory and numerical two-storey framed structures. A number of single notch-type damage scenarios of different locations and severities are investigated. To simulate field-testing conditions, numerically simulated data is polluted with white Gaussian noise of up to 10% noise-to-signal-ratio. The results from both numerical and experimental investigations show the proposed method is effective and robust for detecting notch-type damage in structures.
Sirivivatnanon, V, Thomas, WA & Waye, K 2012, 'Determination of free chlorides in aggregates and concrete', Australian Journal of Structural Engineering, vol. 12, no. 2, pp. 151-158.
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Chlorides exist as either 'bound' or 'free' chloride in concrete. It is well recognised that it is the free chloride that contributes to steel depassivation and subsequent corrosion in concrete. In measuring the amount of chlorides in aggregates and concrete, both 'water-soluble' and 'acid-soluble (total) chloride' test methods have been used. The aggressiveness of the extractive techniques determines the type and amount of chlorides. This was investigated in terms of the type of extracting agent and degree of fractured surface of the materials. It was found that the use of boiling water on materials passing 850-micron sieve offered a well balanced measure of the free chloride contents in aggregate. The findings were also confirmed valid in testing hardened concrete. © Institution of Engineers, Australia 2012.
Sofi, M, Mendis, PA & Baweja, D 2012, 'Estimating early-age in situ strength development of concrete slabs', CONSTRUCTION AND BUILDING MATERIALS, vol. 29, no. 1, pp. 659-666.
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Post-tensioned concrete members are becoming very popular around the world due to structural efficiencies. However, some important issues related to concrete properties are not resolved yet. A more accurate prediction of the in situ early-age strength is
Sriravindrarajah, R, Wang, NDH & Ervin, LJW 2012, 'Mix Design for Pervious Recycled Aggregate Concrete', International Journal of Concrete Structures and Materials, vol. 6, no. 4, pp. 239-246.
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Pervious concrete is a tailored-property concrete with high water permeability which allow the passage of water to flow through easily through the existing interconnected large pore structure. This paper reports the results of an experimental investigation into the development of pervious concrete with reduced cement content and recycled concrete aggregate for sustainable permeable pavement construction. High fineness ground granulated blast furnace slag was used to replace up to 70 % cement by weight. The properties of the pervious concrete were evaluated by determining the compressive strength at 7 and 28 days, void content and water permeability under falling head. The compressive strength of pervious concrete increased with a reduction in the maximum aggregate size from 20 to 13 mm. The relationship between 28-day compressive strength and porosity for pervious concrete was adversely affected by the use of recycled concrete aggregate instead of natural aggregate. However, the binder materials type, age, aggregate size and test specimen shape had marginal effect on the strength-porosity relationship. The results also showed that the water permeability of pervious concrete is primarily influenced by the porosity and not affected by the use of recycled concrete aggregate in place of natural aggregate. The empirical inter-relationships developed among porosity, compressive strength and water permeability could be used in the mix design of pervious concrete with either natural or recycled concrete aggregates to meet the specification requirements of compressive strength and water permeability.
Tabatabaiefar, SHR, Fatahi, B & Samali, B 2012, 'Finite difference modelling of soil-structure interaction for seismic design of moment resisting building frames', Australian Geomechanics Journal, vol. 47, no. 3, pp. 113-120.
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The importance of Soil-Structure Interaction (SSI) both for static and dynamic loads has been well established and the related literature spans at least 30 years of computational and analytical approaches for solving soil-structure interaction problems. Since the 1990s, great effort has been made to substitute the classical methods of design by new ones based on the concept of performance-based seismic design. Also, the necessity of estimating the vulnerability of existing structures and assessing reliable methods for their retrofit have greatly attracted the attention of engineering communities in most seismic zones throughout the world. In the present study, in order to draw a clear picture of soil characteristics effects on seismic response of moment resisting building frames, a ten storey moment resisting building frame, resting on shallow foundation, is selected in conjunction with three soil types with shear wave velocities less than 600m/s, representing soil classes Ce, De and Ee, according to Australian Standard AS 1170.4. The structure is modelled considering the three mentioned types of the soil deposits employing Finite Difference approach using FLAC 2D software. Fully nonlinear dynamic analyses under influence of different earthquake records are conducted, and the results of the different cases are compared and discussed. The results indicate that as shear wave velocity and shear modulus of the subsoil decrease, inter-storey drifts and subsequently the necessity of considering SSI effects in seismic design of moment resisting building frames increase. In general, by decreasing the subsoil stiffness, the effects of soil-structure interaction become more dominant and detrimental to the seismic behaviour of moment resisting building frames. These effects substantially alter performance level of the building model resting on soil classes De and Ee from life safe to near collapse. Consequently, structural safety for the mentioned building frames ...
Tao, M, Li, X & Wu, C 2012, 'Characteristics of the unloading process of rocks under high initial stress', Computers and Geotechnics, vol. 45, pp. 83-92.
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The unloading process of rocks under high initial stress is complex, and verifying the mechanism of the unloading process in the field or in a laboratory is not straightforward. In this study, the unloading process of rocks under high initial stress was characterised by a mathematical physics model, which was then implemented in the finite element program LS-DYNA for analysis. In particular, the implicit and explicit methods were performed in sequence in the finite element simulation of rocks with initial stresses. In the numerical simulation, the characteristics of the dynamic unloading process of rocks were investigated for various peak initial stresses, initial stress release paths and initial stress release rates (ISRRs). The numerical results indicated that the rock failure could be induced by the release of the initial stress; furthermore, there is a relationship between the magnitude of the unloading failure and the peak initial stresses, the initial stress release paths and the ISRRs. When the initial stresses were at the same level, the equivalent initial stress release rate (EISRR) was introduced to quantitatively describe the characteristics of the unloading process. Using the numerical results, the unloading failure process was characterised, and a method for the static stress initialisation-dynamic unloading of rock was developed. © 2012.
Tennakoon, N, Indraratna, B, Rujikiatkamjorn, C, Nimbalkar, S & Neville, T 2012, 'The Role of Ballast-Fouling Characteristics on the Drainage Capacity of Rail Substructure', Geotechnical Testing Journal, vol. 35, no. 4, pp. 629-640.
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Abstract The ballast layer is designed to be free draining, but when the voids of the granular medium are wholly or partially filled because of the intrusion of fine particles, the ballast is considered to be “fouled.” To ensure acceptable track performance, it is necessary to maintain good drainage within the ballast layer. This paper critically examines the current methods commonly used for evaluating the degree of ballast fouling and, because of their limitations, a new parameter, “void contaminant index” is introduced. A series of large-scale constant head hydraulic conductivity tests were conducted with different levels of fouling to establish the relationship between the void contamination index and the associated hydraulic conductivity. Subsequently, a numerical analysis was executed to simulate more realistic two-dimensional flow under actual track geometry capturing the drainage capacity of ballast in relation to the void contamination index. In the context of observed test data, the drainage condition of the track could be classified into different categories together with a classification chart capturing the degree of fouling. The contents of this paper have already been considered in track maintenance schemes in the states of Queensland and New South Wales.
Thomas, D, Ding, G & Crews, K 2012, 'Sustainable timber use in the australian housing market: Are consumers willing to pay the price?', International Journal for Housing Science and Its Applications, vol. 36, no. 4, pp. 221-230.
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A large proportion of traditional Australian homes contained timber floors and timber exterior cladding until the advent of the standard concrete slab/brick veneer house. Up to 95% of new homes are built by project home companies and the majority of these contain an external envelope consisting of concrete flooring, clay brick walls and concrete tile or steel sheet roofing. This design is currently driven by consumer's expectation of low cost, durable homes that are completed within restricted time limits. There is now a price premium on bespoke housing projects that differ materially or otherwise from a limited set of designs offered by project home firms. The adoption of concrete and brick homes originated from a perceived advantage of longevity, low maintenance and thermal comfort. Innovation in wood treatments, wood protection and insulation have provided solutions to these issues so that timber is now a viable option with added benefits such as environmental sustainability and erection speed. Australian consumers have a growing awareness and desire to live in a way that is sustainable and are making choices that reflect this attitude. This has been demonstrated through the high adoption rate of recent government-supported schemes such as subsidized insulation and solar panel installation. This paper aims at investigating homeowner's perception of timber as a sustainable building product, the desire of homeowners to use sustainable building products, and the willingness of homeowners to pay a premium to live sustainably. This paper highlights Australian homeowners reluctance to use the most sustainable building materials even when they are willing to pay for a more environmentally sustainable home. This paper presents the results of a questionnaire survey to homeowners in the city of Sydney, New South Wales, Australia and some strategies on how to increase the use of timber in new housing projects in Australia. Copyright © 2012 IAHS.
Visintin, P, Oehlers, DJ, Wu, C & Griffith, MC 2012, 'The reinforcement contribution to the cyclic behaviour of reinforced concrete beam hinges', Earthquake Engineering & Structural Dynamics, vol. 41, no. 12, pp. 1591-1608.
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SUMMARYThe cyclic behaviour of plastic hinges is an essential component in tracking the behaviour of RC frames to failure, not only for monotonically increasing force/pressure loads such as under extreme wind loads but also for dynamic displacement‐driven loads such as under earthquake ground motions. To describe member deformations at ultimate loading, traditional moment–curvature techniques have required the use of an empirical hinge length to predict rotations, and despite much research a definitive generic expression for this empirical hinge length is yet to be defined. To overcome this problem, a discrete rotation approach, which directly quantifies the rotation between crack faces using mechanics, has been developed for beams and been shown to be accurate under monotonic loading. In this paper, the discrete rotation approach for monotonic loads is extended to cope with cyclic loads for dynamic analyses, and this has led to the development of a new partial interaction numerical simulation capable of allowing for reversals of slip of the reinforcing bars. This numerical tool should be very useful for the nonlinear analysis of reinforced concrete beams and reinforced concrete columns with small axial loads under severe dynamic loads. Copyright © 2011 John Wiley & Sons, Ltd.
Visintin, P, Oehlers, DJ, Wu, C & Haskett, M 2012, 'A mechanics solution for hinges in RC beams with multiple cracks', Engineering Structures, vol. 36, pp. 61-69.
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Wu, C 2012, 'Research development on protection of structures against blast loading at University of Adelaide', AUSTRALIAN JOURNAL OF STRUCTURAL ENGINEERING, vol. 13, no. 1, pp. 97-109.
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Wu, C 2012, 'Research development on protection of structures against blast loading at University of Adelaide', Australian Journal of Structural Engineering, vol. 13, no. 1, pp. 97-109.
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This paper presents a review of research into the protection of structural members against blast loading at The University of Adelaide, including experimental, analytical and numerical studies on characteristics of blast loading, blast resistance of structural members and mitigation of blasts effects on structural members using retrofitting techniques. Explosive blasts are investigated experimentally and numerically to study the distributions of peak overpressure and impulse generated from spherical charges and cylindrical charges with different orientations in unconfined and confined environments. A series of blast tests on reinforced concrete (RC) slabs, ultra-high performance concrete (UHPC) slabs, and aluminium foam protected RC slabs was conducted to investigate the performance of those slabs under blast loads. With the blast testing data numerical models including single degree of freedom model, finite difference model and final element model, have been developed and validated and those numerical models are then used to analyse the blast effects of RC, UHPC and foam protected RC slabs. Investigation of mitigation of blast effects on masonry structures is also addressed.
Xiao, J, Li, W, Fan, Y & Huang, X 2012, 'An overview of study on recycled aggregate concrete in China (1996–2011)', Construction and Building Materials, vol. 31, pp. 364-383.
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A series of investigations on the mechanical property, durability, and the structural performance of recycled aggregate concrete (RAC) have been carried out in the past 15 years (1996-2011) in China. The achievements of researches on recycled concrete are relatively sufficient to review and share with investigators from other countries. Some research progress of micro- and meso-structure of RAC is introduced in the first part of this paper. The second part of this paper is devoted to the mechanical properties of RAC material: strength, elastic modulus, Poisson's ratio, stress-strain curve. The third part of the paper gives research on durability of RAC: carbonization, chloride penetration, shrinkage and creep. The last part presents a review on the structural performance of RAC elements and structures: beams, columns, slabs, beam-column joints, shear walls as well as frames made with RAC. Results of all researches reveal that with proper design and construction, it is safe and feasible to apply RAC as a structural material in civil engineering. Moreover, in this paper, the relevant research results of RAC obtained in China and from other countries are compared and discussed. This review provides helpful directions to those who are already engaged in this research, and points out areas which are needed to promote safe and economic use of RAC. © 2012 Elsevier Ltd. All rights reserved.
Xiao, J, Li, W, Sun, Z & Shah, SP 2012, 'Crack Propagation in Recycled Aggregate Concrete under Uniaxial Compressive Loading', ACI Materials Journal, vol. 109, no. 4, pp. 451-462.
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In this study, systematic experimental research was carried out to investigate the crack propagation of modeled recycled aggregate concrete (MRAC) and recycled aggregate concrete (RAC) under uniaxial compressive loading. A two-dimensional (2-D) nondestructive digital image correlation (DIC) technique was applied to record the initiation and propagation of surface microcracks. The obtained results indicated that the fracture process and crack pattern of MRAC were greatly affected by the relative strength of new mortar and old mortar. It was also found that the failure mode of RAC was related to the water-cement ratio (w/c) of the mixture. The bond cracks first appeared around the weak interfacial transition zones (ITZs) and then propagated into the mortar region by connecting with each other. The failure pattern of MRAC can provide insight into the influences of the mechanical properties of each phase on the failure mechanism of RAC. © 2012, American Concrete Institute. All rights reserved.
Yang, L, Thomas, P & Stuart, B 2012, 'Discrimination of thermally treated low density polyethylenes using DSC and principal component analysis', Journal of Thermal Analysis and Calorimetry, vol. 108, no. 2, pp. 445-448.
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The potential for differential scanning calorimetry (DSC) as a tool for the discrimination of forensic polymer specimens is investigated for a series of commercial low density polyethylene (LDPE) samples. Variation in the melting temperatures of 'as received' samples was found to be too small for its use in sample discrimination. The melting behaviour of thermally treated samples, quenched from the melt in liquid nitrogen followed by annealing at temperatures below the melting temperature, showed promise in discrimination potential. The application of principal component analysis to aid discrimination demonstrated the necessity in using a controlled thermal history to aid the discrimination process. The clustering of the LDPEs based on the factors selected demonstrated the potential of DSC for the discrimination of forensic LDPE samples.
Ahmad, A, Huang, S, Wang, JJ, Dissanayake, G & IEEE 1970, 'A New State Vector and a Map Joining Algorithm for Range-Only SLAM', 2012 12TH INTERNATIONAL CONFERENCE ON CONTROL, AUTOMATION, ROBOTICS & VISION (ICARCV), International Conference on Control, Automation, Robotics and Vision, IEEE, Guangzhou, China, pp. 1024-1029.
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This paper presents a new state vector and a map joining algorithm for range-only SLAM problems. Local maps are built by least squares optimization using the new state vector and a landmark initialization strategy which is an improvement on our preliminary work [1]. The map joining algorithm combines the local maps using least squares optimization to maintain the estimation consistency. Both the local map building and the map joining algorithm maintain a list of 'unused range observations' to minimize the potential for information loss. The accuracy of the proposed method is evaluated using a simulation dataset, and an experimental dataset provided by the Robotics Institute at Carnegie Mellon University (CMU). © 2012 IEEE.
Alamdari, M, Li, J & Samali, B 1970, 'A FRF-based damage detection method utilising wavelet decomposition', From materials to structures: Advancement through innovation, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 873-877.
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Damage in a structure causes deviation in dynamic responses of the structure either in frequency or time domain in comparison with its healthy status. The purpose of this study is to present a new damage detection method in order to detect and localize the structural damage. This novel algorithm is based on the directly-measured frequency response functions (FRFs). The approach is composed of three major steps: first, developing the curvature of FRFs which produces spatially distributed shape functions at each frequency coordinate, secondly, normalization of FRFsâ curvature in order to enhance the influence of the lower-frequency-band data; finally decomposition of the obtained profiles (normalized version of FRFsâ curvature) by conducting wavelet analysis to detect any possible structural abnormality through structure. The combination of these three steps leads to a robust algorithm in detection and localisation of any damage in the structure even at small levels which other FRF-based methods were unable to detect. There are some benefits with the presented method: first, this method does not need higher-frequency-range data which is hard to obtain in most civil applications; second, there is no need for baseline data from the intact structure; This is particularly attractive for practical applications as it opens an opportunity for online monitoring of the structural integrity without demanding for any previous data records of the structure. The performance of the method is evaluated on a numerical model and the effect of different parameters such as the location of the excitation point, the level and the location of the damage was studied; the results demonstrated that the method can efficiently identify the location of the damage in the structure even for damage at small levels.
Almabrok, M, McLaughlan, R & Vessalas, K 1970, 'Characterisation of cement mortar containing oil-contaminated aggregates', From Materials To Structures: Advancement Through Innovation - Proceedings Of The 22nd Australasian Conference On The Mechanics Of Structures And Materials, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 1091-1096.
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Oil spills, leakage and other releases of products from petroleum industry are a source of contamination and are recognised as a major environmental concern. The current treatment technologies for these materials are either cost prohibitive and/or the treated products have to be sent to land fill without any potential end-use, thereby rendering these solutions unsustainable. Cement-based stabilisation/solidification is an emerging technology; however there is currently quite limited knowledge on the effect of oil on the cement solidification process and its consequent effect on the performance of fresh and hardened properties of the resultant cementitious mix. The purpose of conducting this study is to determine the appropriateness of the mortar for various end-uses when incorporating mineral oil additions up to 10% of the aggregate mass. Increased oil content in the cement mortar was found to increase setting time and decrease air content. The compressive strength decreased by 78% compared to the control at 28 days age. However, since the compressive strength covered a wide range of values, various feasible end-use scenarios for oil contaminated mortar exist.
Anantanasakul, P, Indraratna, B, Nimbalkar, SS & Neville, T 1970, 'Effects of Geosynthetic Reinforcement on Performance of Ballasted Rail Track', Proceedings of the International Conference on Ground Improvement & Ground Control, International Conference on Ground Improvement & Ground Control, Research Publishing Services.
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Angus, K, Thomas, P, Vessalas, K & Ray, A 1970, 'Investigation of ground flint glass as a supplementary cementitious material in autoclaved lime-silica binders', From Materials to Structures: Advancement Through Innovation - Proceedings of the 22nd Australasian Conference on the Mechanics of Structures and Materials, ACMSM 2012, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 247-249.
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A potential application for the use of cullet glass is as a supplementary cementitious material (SCM). Cullet is a ground soda-lime-silica glass waste that has the potential to react with calcium hydroxide (CH) produced as a secondary product from the hydration of Portland cement (PC) in forming principal calciumsilicate- hydrate (C-S-H) strengthening phases. Additionally, the relatively high sodium content of the glass has the potential to act as precursor for the activation of aluminosilicates such as fly ash (FA). This paper investigates this potential by using these wastes in autoclaved hydrated lime CH-silica systems. Compressive strengths of autoclaved compacted cylinders were evaluated and the results demonstrate that the addition of ground glass provides higher strength, when used as a partial silica substitute, and aids in the activation of FA. © 2013 Taylor & Francis Group.
Aoki, Y, Samali, B, Saleh, A & Valipour, H 1970, 'Assessment of key response quantities for design of a cable-stayed bridge subjected to sudden loss of cable(s)', From materials to structures: Advancement through innovation, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 387-392.
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Stays of cable-stayed bridges have potential to lose their support instantly by extreme loadings such as earthquake, thunder strike, vehicle impact, wind and malicious attacks. The sudden loss of cable(s) provides unpredictable stress redistribution on the deck and towers, as well as the large deflections of the entire bridge. This phenomenon is the cause of one of the most critical situations for the cable-stayed bridges, termed âzipper-type collapseâ (i.e. the mechanism of the progressive collapse by the redistribution of stresses). Considering such a sudden loss of cable in the design of a cable-stayed bridge is essential. Although cable loss scenarios are associated with material as well as geometrical nonlinearities, in design of cable-stayed bridges, such an extreme loading scenario is analysed typically by using linear elastic models. In this paper, a linear elastic 2D and a fully nonlinear 3D finite element model of an idealised steel cable-stayed bridge are developed and analysed to determine the effect of sudden loss of cable on the progressive collapse of the bridge at global and local stress levels.A parametric dynamic analysis for the bridge model with different cable loss scenarios under symmetrical or unsymmetrical load cases is investigated. The bridge model studied in this paper showed that the 2D model can adequately capture global behaviour of the bridge. The 3D model showed the most significant stress concentration occurring under the symmetrical case are limited to small areas and are negligible.
Askari, M, Li, J & Samali, B 1970, 'Adaptive multiple forgetting factor recursive least square (AMFF-RLS) for real-time structural identification', From materials to structures: Advancement through innovation - 22nd Australian Conference On The Mechanics Of Structures And Materials, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 879-884.
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System identification refers to any systematic way of deriving or improving models of systems through the use of experimental and field testing inputâoutput data. In the field of civil engineering, identification of the state of the structure during the dynamic loads, such as earthquake, to predict the current state of the structure and detect any damage or hazard,when it occurs, has posed a great challenge to the research community. Therefore, online and real-time structural parameters identification has recently drawn more attractions, although few research works have been reported especially for cases where measurement data are contaminated by high level noise. The Recursive Least Square with single forgetting factor has been widely used in estimation and tracking of time-varying parameters in the fields of electrical and mechanical engineering. However, when there are multiple parameters that each (or some) varies with a different rate, this method cannot perform well. On the other hand, a priori information on the changing rate of the parameters might not be available, and the forgetting factors must be updated adaptively. This paper presents a new adaptive tracking technique, based on the Recursive Least Square (RLS) approach with Adaptive Multiple Forgetting Factors (AMFF). The proposed method considers an adaptive rule for each of the forgetting factors assigned to each of the parameters and thus, enables simultaneous estimation of the time-varying stiffness and damping of the storeys of the structure. Numerical examples show that results of this RLS-based approach are accurate and robust, even when the observed data are contaminated with different types and significantlevels of noise.
Askari, M, Li, J & Samali, B 1970, 'Application of extended, unscented, iterated extended and iterated unscented Kalman Filter for real-time structural identification', Advances in Applied Mechanics Research, Conference Proceedings - 7th Australasian Congress on Applied Mechanics, ACAM 2012, Australasian Congress on Applied Mechanics, Engineers Australia, Adelaide, pp. 1041-1051.
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System identification refers to any systematic way of deriving or improving models of dynamical systems through the use of experimental and field testing input-output data. In the field of civil engineering, identification of the state of a structure during service condition under dynamic loading, such as earthquake, in order to detect any damage as it occurs, has posed a great challenge to the research community. Therefore, online and real-time structural identification has attracted a great deal of attentions in the structural engineering research over the past decades, especially when input-output measurement data are contaminated by high-level noise. Among real-time identification methods, one of the most successful and widely used methods for estimation of states and parameters is the Kalman filter and its various nonlinear extensions like Extended Kalman Filter (EKF) and iterated Extended Kalman Filter (IEKF). However, these methods are not effective in the case of highly nonlinear problems. To overcome the problem, two filtering techniques, namely unscented Kalman filter (UKF) and iterated unscented Kalman filter (IUKF), have been recently developed to handle any functional nonlinearity. In this paper, an investigation has been carried out on the aforementioned methods for their effectiveness and efficiencies through a highly nonlinear SDOF structure as well as a two-storey linear structure. Results show that, although IEKF is an improved version of EKF, the IUKF, in most of cases, produces better results on state estimation and parameter identification than UKF and IEKF. IUKF is also more robust to measurement noise levels compared to the other approaches.
Aslani, F & Nejadi, S 1970, 'Bond Constitutive Relationship for Steel Fiber Reinforced Self-Compacting Concrete', Proceeding for the BOND IN CONCRETE 2012: Bond, Anchorage, Detailing conference, Bond in Concrete, Publisher creations, Manerbio (Brescia), Italy, pp. 931-939.
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Steel fiber reinforced self-compacting concrete (SFRSCC) is a relatively new composite material which congregates the benefits of the SCC technology with the profits derived from the addition of fiber to a brittle cementitious matrix. Steel fibers improve many of the mechanical properties of self-compacting concrete (SCC) elements including tensile strength, ductility, toughness, energy absorption capacity, and fracture toughness. This paper investigates the bond characteristics between steel fiber and SCC based on the available experimental results. An analytical steel fiber pullout model proposed by Dubey (1999) is modified by considering the different mechanical properties of SCC and different fiber types (smooth, hooked) and in-clination. In order to take into account the effect of the fiber inclination in the pullout model, apparent shear strengths and slip coefficient are incorporated to express the variation of pullout peak load and the augmentation of peak slip as the inclination angle increases. These variables are expressed as functions of the inclination angle.
Aslani, F & Nejadi, S 1970, 'Comparison of the analytical models to determine modulus of rupture of self-compacting concrete and conventional concrete', From Materials To Structures: Advancement Through Innovation - Proceedings Of The 22nd Australasian Conference On The Mechanics Of Structures And Materials, Australasian Conference On The Mechanics Of Structures And Materials, CRC Press, Sydney, Australia, pp. 1105-1112.
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Self-compacting concrete (SCC) can be placed under its own weight with no vibration efforts and is cohesive enough to be handled without segregation and bleeding. Modification in the mix design may have an influence on the materialâs mechanical properties. Therefore, it is important to investigate that whether all of the assumed hypotheses for conventional concrete (CC) to design structures are also valid for SCC structures. Modulus of rupture (MOR) or flexural strength is an indirect measurement of the tensile strength of concrete and is used to predict cracking moment in critical regions in reinforced concrete members. This paper reviews and compares the accuracy of the five models for prediction of MOR for the SCC mixtures and ten models for the CC mixtures. In addition, comparisons are made between the predicted values by MOR models and actual measured flexural strength of about 175 SCC mixtures.
Bano, V, Vivas, J, Rodriguez, S & Crews, K 1970, 'Numerical and experimental analysis of the vertical vibrations on several designs of timber footbridges', World Conference on Timber Engineering 2012, WCTE 2012, pp. 101-105.
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Numerical and experimental vertical natural frequencies of simply-supported, two hinged arch and trass timber footbridges were analyzed. The footbridges were designed la con form to Ivuroeode 5 and each typology presented different spans (12,27 and 14 m, respectively). The theoretical values of natural frequency for different mode shapes were calculated using a numerical model. The experimental modal parameters were then measured using accelerometers attached underneath the bridge girders and the impact was induced by hitting with an instrumented impact hammer. The results of the acceleration vvere measured at five points on each girder, in order to obtain the first and second modal shape in bending and in torsion. The experimental results obtained for first bending modal shape (9,9, 6.4 and 7.3 Ik, respectively) and first torsion modal shape (12.8, 6.9 and 15.7 Hz. respectively) presented no risk of resonance according to Spanish regulations (IAP 201I). Furthermore, the relationship between experimental results and numerical simulation vvere analyzed. Once the numerical model was validated, new footbridges vvere designed based on one typology to study the effect of span on natural frequency. The paper also presents a frequency range classification corresponding to the risk of resonance due to pedestrian loading. Copyright © (2012) by WCTE 2012 Committee.
Brennan, J, Heilmann, A & Pundt, H 1970, 'An information systems approach to developing adaptation strategies', Proceedings of the European, Mediterranean and Middle Eastern Conference on Information Systems, EMCIS 2012, European, Mediterranean and Middle Eastern Conference on Information Systems, ISEing, Munich, Germany, pp. 231-241.
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The aim of this paper is to develop an Information Systems approach that helps overcome the limitations of self-organised networks and enables coordination amongst its stakeholders. Developing Climate Change Adaptation Strategies (CCAS) often involves loosely connected stakeholders, which in turn results in a largely self-organised network. This is in stark contrast to Romsdahl's findings that the development of CCAS requires coordinated networks. In want for an appropriate means to coordinate the work of mainly self-organised networks; networked enterprises are examined to transfer its techniques into the CCAS domain. Workspaces and Portals are discussed and their potential role as an Environmental Information System (EIS) demonstrated. A case study on CCAS Regional Development is outlined to illustrate the concepts introduced.
Fatahi, B, Engelbert, D, Mujic, S & Khabbaz, H 1970, 'Assessment of Surcharging on Strength and Stiffness of Cement Treated Clays', Grouting and Deep Mixing 2012, Proceedings of the Fourth International Conference on Grouting and Deep Mixing, American Society of Civil Engineers, Louisiana, USA, pp. 272-280.
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Deep soil mixing (DSM) is a ground improvement technique most appropriate in applications aimed at improving properties of soft clay, which is very sensitive to temperature and water content changes. This paper presents an experimental study capturing effects of surcharge application during curing time on the stress-strain behaviour of DSM columns. An investigation has been undertaken into the effects of varying surcharges, applied immediately after mixing, ranging from 40kPa to 120kPa, on the strength and stiffness of cement treated kaolinite clay samples with different cement contents. The results of uniaxial tests are analysed to illustrate how the Young's modulus and unconfined compressive strength (UCS) are influenced under varying surcharges. Results confirm a promising increase in strength and stiffness with increased preloading. Results are significant, in that desired DSM column strengths can be achieved through a combination of cement and surcharging, as opposed to increasing the cement content; thus significantly reducing the carbon footprint induced by cement production. © 2012 American Society of Civil Engineers.
Fatahi, B, Far, H, Sadeghi Hokmabadi, A & Samali, B 1970, 'Significance of bedrock depth in dynamic soil-structure interaction analysis for moment resisting frames', 2nd International Conference on Performance-Based Design in Earthquake Geotechnical Engineering, International Conference on Performance-Based Design in Earthquake Geotechnical Engineering, Associazione Geotecnica Italiana - Roma, Taormina, Italy, pp. 1396-1406.
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In this study, a fifteen storey moment resisting building frame, resting on a shallow foundation, is selected in conjunction with two clayey soils with the shear wave velocities less than 600m/s, representing soil classes De and Ee, according to AS 1170.4. Different bedrock depths including 10m, 20m, and 30 m are employed in the numerical modelling using finite difference software FLAC 2D. Fully nonlinear dynamic analysis under the influence of different earthquake records is conducted, and the results of the three different cases are compared and discussed. The results indicate that the dynamic properties of the subsoil such as shear wave velocity as well as bedrock depth play significant roles in seismic response of the building frames under the influence of soil-structure interaction. As the bedrock depth increases, lateral deflections and inter-storey drifts of the structures increase. These effects can change the performance level of structures from life safe to near collapse or total collapse. Therefore, the conventional design procedure excluding SSI is not adequate enough to guarantee the structural safety for the building frames resting on soft soil deposits.
Fatahi, B, Khabbaz, H & Fatahi, B 1970, 'Application of Polypropylene and Carpet Fibres to Improve Mechanical Properties of Cement Treated Clay', International Symposium on Ground Improvement IS-GI, PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM, SIMSG, Brussel, pp. 303-308.
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In this study, the influence of two types of fibre reinforcement, namely polypropylene and carpet waste fibres, on mechanical properties of cement treated kaolinite is investigated. The results of unconfined compressive strength testing of 63 cylindrical samples of cement treated kaolinite with varied cement and fibre contents are analysed to discern the relationships between these parameters and the key mechanical properties, including unconfined compressive strength and stiffness of treated soil. The fibre reinforcement increases the peak strength. The initial Young's modulus of the fibre reinforced cement treated kaolinite increases by adding polypropylene whereas slightly decreases when adding carpet fibres. The improvement of mechanical properties was far more pronounced with the introduction of polypropylene than carpet waste fibres. The implication of these findings is a cost effective and environmentally friendly alternative compare to increasing cement content in soil to achieve the required mechanical properties, particularly where the strength is a governing consideration.
Fatahi, B, Khabbaz, H & Le, TM 1970, 'Improvement of rail track subgrade using stone columns combined with geosynthetics', ADVANCES IN TRANSPORTATION GEOTECHNICS II, International Conference on Transportation Geotechnics (ICTG), CRC Press - Taylor & Francis Group, Hokkaido, Japan, pp. 202-206.
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This study seeks to identify the effectiveness of ground improvement using stone columns in controlling settlement of soft soils when placed under the dead loads of the rail structure and the large live loads of freight trains. The employed numerical study assesses the relationship between the column position in the track cross section and the overall settlement of the ballasted rail formation. The numerical results show that the overall settlement of the track reduces significantly with the use of stone columns close to the centre of the track and not just under the rail. In addition, application of one layer of geogrids between sub-ballast and sub-grade assists to reduce the maximum settlement of track decreasing the future maintenance costs. © 2012 Taylor & Francis Group.
Firouzianhaji, A, Saleh, A & Samali, B 1970, 'Finite element modeling of a beam-column connection in industrial storage racking structures', From materials to structures: Advancement through innovation - 22nd Australian Conference On The Mechanics Of Structures And Materials, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 813-818.
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Industrial storage racking structures are typically constructed using cold-formed steel sections and contain moment resisting frames in which the columns have slots punched in at regular intervals to enable the beams to be clipped into position at any desired high. Hence unlike in conventional steel construction the beam to column connections are typically not bolted or welded but rely primarily on hooks and bearing contact between components to achieve the connection. As a consequence, such connections are semi-rigid and when loaded to failure they exhibit non-linear stiffness characteristics that are attributed to both geometric and material non-linearity. Due to the slenderness and flexibility of industrial racks, it is important therefore to consider the effect of connection flexibility when preparing structural models of such racking systems. A research project is currently underway at University of Technology, Sydney to investigate the behaviour of such connections and its effect on the dynamic response of industrial storage racking systems. An important part of this research, which is the focus of this paper, is devising suitable finite element models of the connections and verifying their accuracy against experimental moment-rotation curves. By considering the real conditions that govern the connection response, the FE models include different features such as 3D geometric details, non-linear material behavior, large displacements and the phenomena of contact non-linearity. This paper presents finite element models of a typical beam-column connection used in industrial storage racking structures and compares their accuracy against experimental results. The computational effort required in the analysis of different modeling options will also be compared and the adequacy in incorporating the model in a dynamic/Seismic finite element analysis will be discussed.
Fukumoto, T, Thomas, P & Stuart, BH 1970, 'The development of organic consolidants for heritage Sydney sandstones', 2nd International Congress - Chemistry for Cultural Heritage Abstracts, 2nd International Congress - Chemistry for Cultural Heritage Abstracts, Turkish Chemical Society, Istanbul, Turkey, pp. 1-1.
Fukumoto, T, Thomas, P, Stuart, BH, Ray, AS & Guerbois, JL 1970, 'Characterisation of poly(acrylic acid) - montmorillonite composites using TG-MS', 15th International Conference on Thermal Analysis and Calorimetry Abstracts, 15th International Conference on Thermal Analysis and Calorimetry.
Galea, N, Hamedanimojarrad, P, Vessalas, K & Thomas, P 1970, 'Assessment of wollastonite microfibre on drying shrinkage behaviour of cement-based composites', From materials to structures: Advancement through innovation, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 499-504.
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To date there has been limited research carried out on the effect of wollastonite as a microfibre addition to concrete or mortar and its effect on drying shrinkage behaviour. This investigation assesses the effect of wollastonite on drying shrinkage behaviour and compressive strength development of cement-based mortars. Mortar was selected for this study as a behavioural model since it is more sensitive to shrinkage strain than cement-based composites containing coarse-sized aggregate (concrete). Specimens were prepared with the addition of wollastonite at 2%, 4% and 6% by mass of cement. Key indicators of performance evaluated were change in length relative to control mortar exposed to the same storage conditions, as well as change in mass and compressive strength assessment at ages of 7 and 28 days. Results demonstrate that drying shrinkage decreases with the addition of wollastonite, while compressive strength increases with increasing age.
Ge, J, Ding, GK & Phillips, P 1970, 'Sustainable housing - a case study of heritage building in Hangzhou China', Proceedings of 18th Annual Pacific-Rim Real Estate Society Conference, Pacific Rim Real Estate Conference, PRRES, Adelaide, Australia, pp. 1-11.
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Surrounded by high-rise buildings, some two-storey buildings with black roofs are sited along the Xiaohe (Little River) in the north of Hangzhou, China. The buildings were originally built in the late Qing Dynasty (late 19th century) and restored in 2007 by the Hangzhou municipal government. The architectural materials used in the buildings are mainly concrete for the ground floor and timber to the first floor. Three buildings located at Xiaohe Historical Street were investigated to establish whether traditional buildings performed as well as modern buildings. Hourly temperature and humidity readings from September 2009 to August 2010 were recorded for the selected houses. It was concluded through comparisons that the restored heritage buildings provided similar thermal comfort and conditions to modern buildings.
Ghosni, N, Samali, B & Vessalas, K 1970, 'Evaluation of mechanical properties of carpet fibre reinforced concrete', From materials to structures: Advancement through innovation, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 275-279.
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Incorporating suitable material in concrete to improve its performance is an important consideration in the construction industry. Using short fibres as an additive to improve its mechanical properties has been of great attention. Different types of fibres can be used as intrinsic reinforcement to enhance concrete performance. Some of the fibres used in concrete are recycled waste materials such as carpet fibres. This paper aims to investigate the static properties of fibre reinforced concrete (FRC) utilising short carpet fibres shredded and prepared from the carpet industry waste. Thereafter, the economic considerations regarding use of carpet fibres in concrete are discussed. There have not been any comprehensive studies on the effectiveness of carpet fibres in concrete, whereas there is a more comprehensive literature available for other types of fibres such as steel fibres. The effect of adding recycled carpet fibres on the strength development of FRC have been studied and the results are compared to control concrete. Fresh properties i.e. slump, air content and wet density and hardened properties i.e. compressive strength and modulus of rupture after 7 and 28 days of ageing are reported.
Ghosni, N, Vessalas, K & Samali, B 1970, 'Evaluation of fresh properties effect on the compressive strength of polypropylene fibre reinforced polymer modified concrete', From Materials to Structures: Advancement through Innovation - PROCEEDINGS OF THE 22ND AUSTRALASIAN CONFERENCE ON THE MECHANICS OF STRUCTURES AND MATERIALS, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, SYDNEY, AUSTRALIA, pp. 1123-1127.
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Investigations on the characteristics of Fibre Reinforced Concrete (FRC) have gained momentum in the last fewdecades. Employing suitable polymeric fibres and additives in concrete to improve its performance is an important consideration in the construction industry. This research aims to investigative the effect of polypropylene (PP) fibre volume percentage within the concrete mix with and without the presence of polymeric materials on the rheological properties of concrete and its behaviour under compression. PP fibres exhibit low elastic modulus, high elongation and are of low cost, making these fibres most suitable for inclusion in Polymer Modified Concrete (PMC). Traditionally, PP fibres are used in concrete to reduce plastic shrinkage and micro cracking. Accompanying PP fibre additions to PMCs are often styrene butadiene (SB) copolymer latex additions; used to improve the bonding of PP fibres in the cementing matrix. This paper reports on the findings of using different percentages of PP fibres with PMCs incorporating 10% SB latex and 30% fly ash (FA) for partial replacement of Portland cement. Slump, mass per unit volume, air content, high range water reducer agents amount and compressive strength, will be assessed and compared to plain concrete devoid of PP fibre, SB latex and FA additions, after period of curing applied at 7, 28 and 56 days of ageing.
Guo, Y, Zeng, J, Zhu, J, Lin, Z & Li, Y 1970, 'Magnetic Hysteresis of Magnetorheological Fluid under 2D Rotating Magnetic Field Excitation', the 13th International Conference on Electrorheological Fluids and Magnetorheological Suspensions: Book of Abstracts, Gazi University, Ankara, Turkey, pp. 1-2.
Hailu, M, Crews, KI, Gerber, C & S, R 1970, 'LONG âTERM EXPERIMENTAL TEST ON TIMBERCONCRETE COMPOSITE BEAMS', World Conference on Timber Engineering (WCTE 2012), Curran association, Auckland, New Zealand, pp. 249-250.
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The paper presents the results and observations of the long-term test to date. It will discuss numerical models found in the literature and examine their fitness to predict the long-term behavioural responses of the specimens. Recommendations for the long-term design of TCC solutions are also presented.
Hailu, M, Gerber, C, Shrestha, R & Crews, K 1970, 'Interim report on long-term test on timber-concrete composite beams', World Conference on Timber Engineering 2012, WCTE 2012, pp. 80-85.
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A long term laboratory investigation started in August 2010 at the University of Technology, Sydney. The test is conducted on four 5.8m span LVL-concrete composite beams (referred to as TCC beams here onwards) beams with four different connector types: Type 17 screws, four and six notches with coach screw and SFS screws. The materials used are Laminated Veneer Lumber (LVL) for the beams and 32 MPa concrete for the flanges. The investigation is still continuing. The specimens have been under sustained loads of (1.7kPa) whilst the environmental conditions have been cyclically alternated between normal and very humid conditions whilst the temperature remains quasi constant (22 °C) - typical cycle duration is six to eight weeks. With regard to EC 5, the environmental conditions can be classified as service class 3 where the relative humidity of the air exceeds 85% and the moisture content of the timber samples reaches 20%. During the test, the mid-span deflection, moisture content of the timber beams and relative humidity of the air are continuously monitored. The paper presents the results and observations of the long-term test to date. It will discuss numerical models found in the literature and examine their fitness to predict the long-term behavioural responses of the specimens. Copyright © (2012) by WCTE 2012 Committee.
Hailu, M, Gerber, C, Shrestha, R & Crews, KI 1970, 'Geomechanics', From materials to structures: Advancement through innovation, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 617-670.
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This paper presents a comprehensive serviceability investigation that commenced at the University of Technology, Sydney, in August 2010. The tests have been conducted on two 5.8 m span timber concrete composite beams (referred to as TCC beams here onwards) with two different connector types: Type 17 screws and four notches with coach screws. The materials used are laminated veneer lumber (LVL) for the beams and 32-MPa concrete for the flanges. Three serviceability tests were conducted on the beams, two short-term (quasi-static loading) and one longterm (sustained loading) tests. The short-term tests were completed before the start and after the end of the long-term test. Both short-term tests aim to identify the initial and residual stiffness respectively. The ultimate strength of the specimens was also investigated in the course of the last test. During the long-term test (duration of approximately 500 days), the specimens were under a sustained load (1.7 kPa) whilst the environmental conditions were cyclically alternated between normal and very humid conditions â a typical cycle duration was six to eight weeks. The temperature remained quasi constant (22â¦C). The mid-span deflection, LVL-beam EMC and relative humidity of the air were continuously monitored during the test. This test aim to quantify the creep effect of the TCC beams. The paper starts with a brief literature review, continues with a presentation of the laboratory investigations and then presents a thorough discussion and analysis of the long-term and short-term investigations.
Holmes, MI, Crews, KI & Ding, GK 1970, 'Supply chain management strategies for engineered-to-order timber structural systems', Construction, building and real estate conference, Construction, Building and Real Estate Research Conference (COBRA), Arizona State University, Las Vegas, Nevada USA, pp. 1478-1485.
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Supply Chain Management (SCM) originated in the manufacturing industry and then in the construction industry in the mid 1990s. SCM is the management of the entire supply chain instead of individual parts or processes. Its aim is to deliver improved transparency and alignment of the industry's supply chain coordination and positively influence time, cost and quality aspects. Time and cost are important factors that developers and clients use to measure the success of projects. Prefabricated timber structural systems for multi-storey construction are a new innovation, as such time and cost aspects are critical to their commercial viability in the construction industry. They are an engineered-to-order (ETO) product and most SCM literature has neglected the needs of the ETO sector, in particular prefabricated timber structural systems. This paper aims to review the current state-of-art of SCM used in construction and discuss how it can best be adopted for prefabricated timber systems with a focus on improving time and cost. Semi-structured interviews were conducted with industry professionals across the supply chain of timber construction with the aim of identifying which areas of the supply chain have the greatest impact on time and cost. SCM strategies are then suggested to address these areas.
Holmes, MI, Crews, KI & Ding, GK 1970, 'SUPPLY CHAIN MANAGEMENT STRATEGIES FOR MULTISTOREY TIMBER CONSTRUCTION IN AUSTRALIA AND NEW ZEALAND', World Conference on Timber Engineering (WCTE 2012), Curran association, Auckland, New Zealand, pp. 171-172.
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Multi-storey non-residential buildings are a potential area that timber products could be used as structural elements. Two major barriers to timbers use in non-residential construction in Australia and New Zealand (NZ) have been identified as overall designer confidence and fire performance. Another important area that posses as a potential barrier to an increase in timbers use in multi-storey buildings is the current supply chain. Literature has outlined there historically hasnât been a market or demand for large timber buildings constructed over 4 storeys in Australia or NZ. As a result aspects of the supply chain needed to deliver such buildings have remained fragmented and relatively primitive in nature. The supply chain for multi-storey timber buildings in Australia and NZ includes a number of different stages as outlined below in figure 1. Between each stage a number of transportation, material and design information flows occur. This paper focuses on the issues in the supply chain from forestry through to construction and aims to outline the key areas that pose as a risk on the cost and time of multi-storey timber buildings.
Jiang, X, Li, Y, Li, J & Wang, J 1970, 'Electromechanical Modeling of a PZT Disc-type Energy Harvester for Large Force Vibration', PROCEEDINGS OF THE FIRST INTERNATIONAL CONFERENCE ON MECHATRONIC SYSTEM AND MEASUREMENT TECHNOLOGY, 1st International Conference on Mechatronic System and Measurement Technology, SCIENCE PRESS USA INC, Nanjing, PEOPLES R CHINA, pp. 411-416.
Khabbaz, H & Fatahi, B 1970, 'General and Technical Considerations for Implementing High Speed Rail Systems in Australia', PROCEEDINGS OF THE 2012 AGS SYMPOSIUM: ADVANCES IN GEOTECHNICAL ASPECTS OF ROADS AND RAILWAYS, AGS Symposium Advances in Geotechnical Aspects of Roads and Railways, The Australian Geomechanics Society, Darling Harbour, NSW, Australia, pp. 67-78.
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Australia has a number of medium speed rail services such as the Prospector, which runs from East Perth to Kalgoorlie, at speeds of up to 160 km/hr. Speeds as high as 210 km/hr have been reached by the tilt train from Brisbane to Rockhampton. Although there are a few medium speed rail systems in Australia, there is not a passenger rail transport with the high transit speeds seen in other countries. This paper presents the feasibility of implementing high speed rail systems in Australia by looking at the main elements that a high speed train is composed of. This paper also reviews the performance of high speed rail systems around the world and the factors contributed to their success made them successful. The main objective of this study is to look at how the solutions from overseas and how the technical requirements particularly the geotechnical aspects of tracks for a high speed rail system can be applied in Australian existing and new tracks. Australia has its own unique demographic, geographic and economic characteristics and the aim is to identify where there are overlaps between Australiaâs characteristics and countries with high speed rail systems. High speed rail transport might not necessarily be one the best solutions for the transportation at present in Australia, but it can be what a nation needs to succeed in its future transportation system.
Khabbaz, H, Fatahi, B & Nucifora, C 1970, 'Finite Element Methods against Limit Equilibrium Approaches for Slope Stability Analysis', Proceedings of the 11th Australia - New Zealand Conference on Geomechanics - Ground Engineering in a Changing World (ANZ 2012), Australia New Zealand Conference on Geomechanics, Geomechanical Society and New Zealand Geotechnical Society, Melbourne, Australia, pp. 1293-1298.
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A number of powerful numerical models, including limit equilibrium and finite element (FE) methods, have been developed for slope stability analysis in recent decades. The limit equilibrium method contains several limitations, yet is considered the most common approach. However, the advancement of technology has increased the use of the finite element method as it embraces a wider range of features. The limit equilibrium software, SLOPE/W, and the FE program PLAXIS are two common software programs currently employed in geotechnical engineering. Slope analysis using the limit equilibrium method involves a series of slip surfaces dividing ground into vertical slices, and using the static equilibrium equations to calculate the factor of safety (FOS) and stresses for each slice. PLAXIS requires the input of soil properties and elastic-plastic parameters of elements. In this study the properties of a heterogeneous slope, consisting of general fill embankment over soft, slightly overconsolidated clay is implemented in each program. The FOS of slopes is determined for subsequent design requirements, and results are analysed and comparisons are conducted. The effect of Youngâs modulus on the FOS is also discussed. Recommendations are provided based on the results and previously published findings. The contribution of this paper is beneficial to geotechnical engineers, as it discusses the suitability and limitations of each method and assesses reliability of model outputs for slope stability analyses.
Khorsandnia, N, Valipour, H, Shrestha, R, Gerber, C & Crews, K 1970, 'Review on long-term behaviour of timber-concrete composite floors', From Materials to Structures: Advancement through Innovation - Proceedings Of The 22nd Australasian Conference On The Mechanics Of Structures And Materials, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 1053-1058.
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Timber-concrete composite (TCC) beams are made up two materials, i.e. wood and concrete, which exhibit different behaviours under long-term loading. The time-dependent behaviour of TCC beam is not only affected by the long-term load but also driven by the variation of the environmental conditions such as temperature and relative humidity. In particular, the maximum deflection under service loads may govern the design requirement for medium to long span TCC beams subjected to heavy environmental conditions. For such structures, application of simplified methods adopted by different codes may lead to significant errors. Hence investigating the long-term behaviour of TCC beams subject to variable environmental condition is of great importance for designers and researchers. In this paper the research undertaken on long-term behaviour of TCC floors is critically reviewed and the recent findings are highlighted. The most important references in the literature were selected to provide more depth into the time-dependent performance of TCC structure.
Khorsandnia, N, Valipour, HR & Crews, K 1970, 'Finite element modeling of timber-concrete composite beams under short-term loadings', ECCOMAS 2012 - European Congress on Computational Methods in Applied Sciences and Engineering, e-Book Full Papers, 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS), ECCOMAS, Vienna, Austria, pp. 859-867.
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The behavior and performance of timber-concrete composite (TCC) beams have been investigated through different experimental studies on small and full scale specimens under constant and variable ambient conditions, however, finite element modeling of TCC beams and capturing the accurate failure modes of TCC beams is still a challenging task. This paper presents the application of a continuum-based finite element model for loading capacity assessment of TCC beams. A novel approach for modeling TCC beams using the commercial software ABAQUS is introduced in which the behavior of timber and concrete are modeled by Hashin damage and a plastic-damage constitutive law, respectively. Furthermore, the partial interaction between reinforced concrete (RC) slab and timber is modeled by non-linear springs rather than contact elements. Comparison between FE model and available experimental results shows that the developed FE model and adopted constitutive laws for timber and concrete can capture the ultimate load and deflection of TCC beams up to failure with sufficient accuracy.
Khorsandnia, N, Valipour, HR, Gerber, C, Shrestha, R & Crews, K 1970, 'Comparative study on analytical modelling of short- and long-term behaviour in timber-concrete composite systems', World Conference on Timber Engineering 2012, WCTE 2012, Curran association, Auckland, New Zealand, pp. 304-312.
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Recent studies have shown that design of timber-concrete composite (TCC) floors may be governed by serviceability or ultimate limit states and therefore, the design requirements need to be satisfied under both short- and long-term actions. However, the long-term behaviour in medium to long span beams under heavy environmental conditions mainly governs the design. Conducting experimental tests to investigate the behaviour of TCC floors are expensive to run and are time consuming whereas analytical studies offer an efficient alternative for predicting the short- and long-term responses with reasonable accuracy. Time-dependant behaviour of TCC floors is not only affected by the long-term load but also driven by the variation of the environmental conditions such as temperature and relative humidity. The factors that affect the long-term behaviour of TCC floors are quite complex and non-linear. Some simplified as well as more comprehensive approaches have been developed to-date and reported in literature. This paper presents a comparison of several finite element models about the behaviour of TCC systems. It starts with analytical models of timber beams under ultimate and serviceability loads. Furthermore, the finite element models developed to date for predicting the short- and long-term responses of TCC beams are discussed. This paper also outlines a novel method for analysis of TCC beams and highlights the potential of the proposed formulation to capture both the short-and long-term behaviour with sufficient accuracy.
Li, Y & Wang, JJ 1970, 'A robust pedestrian navigation algorithm with low cost IMU', 2012 International Conference on Indoor Positioning and Indoor Navigation (IPIN), 2012 International Conference on Indoor Positioning and Indoor Navigation (IPIN), IEEE, University of New South Wales, Sydney, Australia, pp. 1-7.
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Zero velocity update (ZUPT) is an effective way for pedestrian navigation in a GPS (Global Positioning System) denied environment. The stance phase in each step provides zero velocity measurement for IMU (Inertial Measurement Unit) drift correction. Most previous research, however, gives navigation solutions only for pedestrian walking but not running. Compared with walking, running has a shorter stance phase with qualified as zero velocity. Therefore a stance phase detector for walking may not be capable for running. This paper presents a novel ZUPT algorithm which can achieve robust pedestrian navigation for walking, stair climbing, and running. Our stance phase detector consists of one footstep detector and two zero velocity detectors (ZVDs).The footstep detector is used to mark each new step, and the first ZVD (ZVD1) can successfully detect zero velocity while walking by setting thresholds on both gyroscope and accelerometer measurements. While ZVD1 is failed for running, the second ZVD (ZVD2) is introduced with a relative larger threshold on gyroscope measurement only. The proposed stance phase detector was tested for walking, running and stair climbing. In all cases, most of the footsteps are detected correctly and our ZUPT algorithm can be successfully implemented. Experimental results show that the navigation accuracy of the proposed algorithm for running cases is comparable to that of walking only cases. Tests on a biped robot are being also conducted to verify the effectiveness of the algorithm. © 2012 IEEE.
Li, Y, Li, J & Samali, B 1970, 'A novel adaptive base isolator utilising magnetorheological elastomer', From Materials to Structures: Advancement Through Innovation - Proceedings of the 22nd Australasian Conference on the Mechanics of Structures and Materials, ACMSM 2012, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 763-767.
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Base isolation is the most popular seismic protection technique for civil structures. However, research has revealed that the traditional base isolation system is vulnerable to two kinds of earthquakes, i.e. the near-fault and far-fault earthquakes, due to its passive nature.A great deal of effort has been dedicated to improve the performance of traditional base isolation systems for these two types of earthquakes. Controllable supplementary and energy-dissipation members, such as magnetorheological damper, friction damper or hydraulic fluid damper, have been proposed to reduce seismic responses of the building structures. However, with the introduction of additional control devices, the system complexity increases resulting difficulty in the system implementation and control system design. It would be ideal if a certain level of adaptability could be introduced into base isolation systems while maintaining the traditional outfit. This paper addresses the challenge facing the current base isolation practices and proposes a novel adaptive base isolator as a solution to the problem.A smart rubber, namely, magnetorheological elastomer (MRE), is utilised in this research for its magnetic field-sensitive material property as the main element in the novel device. The tradition base isolator design for a large-scale structure with laminated steel and MRE layers is adopted. To verify and characterise the performance of the MRE base isolator, experimental testing was conducted on UTS shake table facility. Experimental results show that after being energised with magnetic field, the maximum force and the stiffness of the novel device can increase by up to approximately 45% and 37%, respectively.With the field-dependent stiffness and damping, the proposed adaptive base isolator is very promising in meeting the challenges associated with the base isolation systems encountered in practice. © 2013 Taylor & Francis Group.
Li, Y, Luo, X, Ren, XT & Wang, JJ 1970, 'A robust humanoid robot navigation algorithm with ZUPT', 2012 IEEE International Conference on Mechatronics and Automation, 2012 IEEE International Conference on Mechatronics and Automation (ICMA), IEEE, Chengdu,China, pp. 505-510.
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This paper discusses algorithmic concepts, design and testing of a pedestrian dead reckoning (PDR) navigation system based on a low-cost inertial measurement unit (IMU) attached to a user's shoe. The algorithm uses the technique known as 'Zero Velocity Update' (ZUPT) and Kalman Filter consists of 24 error states to reduce IMU errors. We propose a novel dynamic and more robust algorithm to detect the stance phases during walking. The system works well in both 2D (2-dimensional) and 3D environments. Test results show that its horizontal positioning errors are always below 0.3% of the total travelled distance, and the vertical errors are below 0.7%, even on 3D terrain. These results reach the highest position accuracy in available literature. © 2012 IEEE.
Li, Y, Wang, JJ, Xiao, S & Luo, X 1970, 'Dead reckoning navigation with Constant Velocity Update (CUPT)', 2012 12th International Conference on Control Automation Robotics & Vision (ICARCV), 2012 12th International Conference on Control Automation Robotics & Vision (ICARCV 2012), IEEE, Guangzhou, China, pp. 160-165.
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This paper introduces a new algorithm for dead reckoning navigation named Constant Velocity Update (CUPT), which is an extension of popular Zero Velocity Update (ZUPT). With a low-cost IMU (Inertial Measurement Unit) attached to a user's shoe, the proposed algorithm can efficiently reduce IMU errors by detecting not only the stance phases during walking, but also the cases at constant velocity, such as in an elevator or on an escalator. The concept, design and test of a CUPT prototype are detailed in this paper. Test results show that it can effectively detect constant velocity, and its horizontal positioning errors are below 0.45% of the total distance travelled, and vertical errors below 0.25%. This performance reached the highest accuracy in available literature. © 2012 IEEE.
Luo, X, Li, Y, Ren, XT & Wang, JJ 1970, 'Automatic road surface profiling with sensors fusion', 2012 12th International Conference on Control Automation Robotics & Vision (ICARCV), 2012 12th International Conference on Control Automation Robotics & Vision (ICARCV 2012), IEEE, Guangzhou, China, pp. 608-613.
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This paper addresses the issue of automatically profiling the road surface based on sensor fusion. Road surface profiling in this research paper includes road boundary detection, white line detection and lane division. We propose an approach to perform automatic and robust road surface profiling with the fusion of the following sensors: LADAR (Laser Detection and Ranging), GPS (Global Positioning System), INS (Inertial Navigation System), cameras and an odometer. The LADAR is the most important in our research since we propose a new technique that utilizes laser remission to detect white lines. A prototype system has also been developed for testing with the capability of converting profiling results into video files for easy reference and management. The system is able to work under severe weather and light condition, and profiling all lanes within road boundary at one run. Experimental results on a wide variety of roads have demonstrated the effectiveness of the proposed system. © 2012 IEEE.
Mirlatifi, S & Fatahi, B 1970, 'Numerical Analysis of Geosynthetic Reinforced Soil Wall as Bridge Abutment', Proceedings of the 11th Australia - New Zealand Conference on Geomechanics - Ground Engineering in a Changing World (ANZ 2012), Australia New Zealand Conference on Geomechanics, Geomechanical Society and New Zealand Geotechnical Society, Melbourne, Australia, pp. 1383-1388.
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This paper presents the finite element analysis of a geosynthetic reinforced soil wall as a bridge abutment built in Tehran, and the predictions are compared with the available field measurements. This abutment is analysed using both Limit Equilibrium Method (LEM) for stability analysis and Finite Element Method (FEM) for deformation analysis. Two dimensional plane strain finite element model is adopted for the simulation. Polyvinyl Alcohol (PVA) geogrid with high tensile moduli and low creep characteristics has been adopted in this project to limit the deformation of the bridge abutment. In this model, the backfill soil and geogrids simulated adopting Mohr-Coulomb model, and the elasto-plastic material model that only works in tension, respectively. Bridge abutments can be stabilised by including geosynthetic layers with high tensile moduli satisfying both stability and deformation criteria reducing the construction cost and time, post construction deformations, and future maintenance cost.
Moshiri, F, Garven, C, Gerber, C, Valipour, HR, Shrestha, J & Crews, K 1970, 'An investigation on TCC joints using expanded polystyrene light-weight concrete', World Conference on Timber Engineering 2012, WCTE 2012, Curran association, Auckland, New Zealand, pp. 130-135.
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Interest in timber-concrete composite (TCC) floors has increased over the last 30 years. TCC technology relies on timber and concrete members acting compositely together. There are only few researches about the effect of concrete on the structural behaviour of TCCs. For example, the application of light weight concrete (LWC) provides an interesting alternative to minimize the dead load on the timber component. However, LWC exhibits lower strength properties and higher shrinkage compared to conventional concrete. The experimental aspect of the research consists of push-out tests and aims to characterise stiffness, load capacity and failure mode of TCC joints with LWC. The test results are compared to that of TCC joints with conventional concrete (reference) and that found in the literature. This research suggests that there is strong potential for moderate LWC (ρ > 2000 kg/m3) in TCC with limited effect on the structural performance of the TCC element. Whilst the low compressive strength of lighter LWC (ρ < 2000 kg/m3) may have limited applications.
Nabavi, F, Nejadi, S & Samali, B 1970, 'Investigation on the mathematical models of chloride diffusion coefficient in concrete exposed to marine environment', From Materials to Structures: Advancement Through Innovation - Proceedings of the 22nd Australasian Conference on the Mechanics of Structures and Materials, ACMSM 2012, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, SYDNEY, AUSTRALIA, pp. 1153-1158.
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Degradation of reinforced concrete (RC) in maritime structures has become aworldwide problem due to its excessive costs of maintenance, repair, and replacement in addition to its environmental impacts and safety issues. Degradation of both concrete and steel which is the main reason of reduction in the service life of RC structures strongly depends on the diffusion process of moisture and aggressive species. In this paper, the major and popular mathematical models of diffusion process in concrete are surveyed and investigated. Predominantly in these models, the coefficient of chloride diffusion into the concrete is assumed to be constant. Whereas, experimental records indicate that diffusion coefficient is a function of time. Subsequently, data analysis and comparisons between the existing analytical models for predicting the diffusion coefficient with the existing experimental database are carried out in this study. Clearly, these comparisons reveal that there are gaps between the existing mathematical models and previously recorded experimental results. Perhaps, these gaps may be interpreted as influence of the other affecting parameters on the diffusion coefficient such as temperature, aggregate size and relative humidity in addition to the water cement ratio. Accordingly, the existing mathematical models are not adequate enough to predict the diffusion coefficient precisely and further studies need to be performed. At the present, an extensive experimental and analytical research in this regard is being conducted in the CBIR group, University of Technology Sydney. © 2013 Taylor & Francis Group.
Nejadi, S & Aslani, F 1970, 'Bond of deformed reinforcing steel bars embedded in steel fiber reinforced self-compacting concrete', Proceedings for the BOND IN CONCRETE 2012: Bond, Anchorage, Detailing conference, Bond in Concrete, Publisher creations, Manerbio (Brescia), Italy, pp. 757-764.
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Steel fiber reinforced self-compacting concrete (SFRSCC) is a relatively new composite material which congregates the benefits of the SCC technology with the profits derived from the fiber addition to a brittle cementitious matrix. Steel-concrete composite floors, reinforced concrete floors supported by columns or walls and floors on an elastic foundations belong to the category of structural elements in which the conventional steel reinforcement can be partially replaced by the use of SFRSCC. When discussing deformation capacity of structural elements or civil engineering structures manufactured using SFRSCC, one must be able to describe thoroughly both the behavior of the concrete matrix reinforced with steel fibers and the interaction between this composite matrix and discrete steel reinforcement of the conventional type. However, even though the knowledge on bond behavior is essential for evaluating the overall behavior of structural components containing reinforcement and steel fibers, information is hardly available in this area. In this study, bond characteristics of deformed reinforcing steel bars embedded in SFRSCC is investigated.
Ngadimin, A, Vessalas, K, Thomas, P & Hamedanimojarrad, P 1970, 'Investigation of flint glass for partial replacement of fine aggregate in fly ash cement-based mortars', From Materials to Structures: Advancement through Innovation - PROCEEDINGS OF THE 22ND AUSTRALASIAN CONFERENCE ON THE MECHANICS OF STRUCTURES AND MATERIALS, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, SYDNEY, AUSTRALIA, pp. 1159-1164.
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This paper reports on the findings of an investigation into the evaluation of using flint glass (FG) sourced from post-consumer products, available in Australiaâswaste stream, as a replacement of fine aggregate in fly ash (FA) cement-based mortars.Workability, compressive strength and strength activity index were assessed in 3 phases of the research study, which includes: (1) partial replacement of sand by FG at 5%, 10% and 15%; (2) partial replacement of Portland Cement (PC) with FA at 10%, 20% and 30% using a fixed amount of FG; and, (3) variation of water/cementitious material ratio (w/cm) from 0.45 to 0.55 using a fixed amount of FA and FG. Results indicate that FG is suitable for partial substitute of fine sand in mortars up to 15% in terms of compressive strength; however, the value of strength attained is highly dependant on the w/cm used.
Nicholas, A, Ariyaratne, W & Crews, K 1970, 'Capacity of compression members in heritage timber truss bridge', Bridge Maintenance, Safety, Management, Resilience and Sustainability - Proceedings of the Sixth International Conference on Bridge Maintenance, Safety and Management, International Conference on Bridge Maintenance, Safety and Management, CRC Press, Lake Maggiore, Italy, pp. 1895-1902.
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New South Wales Roads and Maritime Services are responsible for maintaining a number of timber bridges on the road network. Many of these are truss bridges which were designed over 100 years ago, and are listed on the State Heritage Register. Since the introduction of the limit state design method for Australian bridge design in the Austroads Bridge Design Code in 1992, there has not been an associated limit states timber bridge design code in Australia. A research and testing program was conducted at the University of Technology, Sydney in 2010 and 2011 in order to develop guidelines to allow reasonable prediction of the capacity of members in these heritage timber truss bridges. The four primary areas that were studied were buckling modes of column assemblies, properties of Australian hardwoods used in timber bridges, shear capacity of timber spacers with bolts along the grain loaded perpendicular to grain, and stress relaxation of timber members loaded in bending with permanent deflections. From this testing and analysis, new guidelines for the design and assessment of heritage timber truss bridges have been developed. The guidelines make use of a critical elastic buckling analysis, as well as a simple interaction formula for bending and compression
Nimbalkar, S, Indraratna, B & Rujikiatkamjorn, C 1970, 'Performance Improvement of Railway Ballast Using Shock Mats and Synthetic Grids', GeoCongress 2012, GeoCongress 2012, American Society of Civil Engineers, JAPAN, pp. 1622-1631.
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Railways in Australia still play a significant role in the intrastate transport of passenger and freight. In recent years, the increased demand for heavier and faster trains has posed greater challenges to railway industry to improve efficiency and stability of track while decreasing track maintenance costs. The ballast layer plays a key role in governing the stability and performance of rail tracks. However, high traffic induced stresses always result in large plastic deformations and degradation of ballast, which in turn leads to significant loss of track stability. This problem becomes severe under impact loading because it accelerates the breakage of ballast particles. Therefore, understanding the complex mechanisms involved with the transfer of impact loads on the substructure and their effect on ballast breakage and degradation is essential when designing new tracks and rehabilitating existing ones. The field trial in Bulli (near Wollongong) demonstrated that in case of train with wheel flats, extremely high pressure can be transmitted to the ballast bed. Installing resilient mats such as rubber pads (shock mats) in rail tracks can lead to attenuation of impact forces and subsequent mitigation of ballast degradation. In view of this, a series of laboratory tests using a high capacity drop-weight impact testing equipment has been carried out to evaluate the effectiveness of shock mats. This paper describes large-scale laboratory testing and full-scale instrumented field trial carried out to quantify the geotechnical behavior of ballast improved by using shock mats and synthetic grids respectively. © 2012 American Society of Civil Engineers.
Noushini, A, Vessalas, K, Ghosni, N & Samali, B 1970, 'Effect of polyvinyl alcohol fibre and fly ash on flexural tensile properties of concrete', From Materials to Structures: Advancement through Innovation - PROCEEDINGS OF THE 22ND AUSTRALASIAN CONFERENCE ON THE MECHANICS OF STRUCTURES AND MATERIALS, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 1165-1170.
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This paper investigates the effect of synthetic fibre and fly ash (FA) on post peak response and fracture properties of concrete. Polyvinyl alcohol (PVA) fibres were added as intrinsic reinforcement to concrete and30%of cementwas replaced with fly ash as an environmental friendly additive to reduce cement consumption. Samples were prepared abiding by relevant standards and tested accordingly. Limit of Proportionality (LOP) of the mentioned concretes has been assessed. Notched rectangular prisms have been tested to evaluate the residual flexural tensile strength and limit of proportionality of conventional and FA modified concrete as well as fibre reinforced concrete (FRC). Cylindrical samples have been tested to determine the compressive strength and indirect tensile strength of each concrete. Tests have been conducted at 28 days of ageing. Results gathered from different mix designs are compared to control and other mixes.
Ravindrarajah, R 1970, 'Acids attack on silica fume high-strength concrete', From Materials to Structures: Advancement through Innovation - PROCEEDINGS OF THE 22ND AUSTRALASIAN CONFERENCE ON THE MECHANICS OF STRUCTURES AND MATERIALS, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, SYDNEY, AUSTRALIA, pp. 1193-1197.
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This paper reports the results of a study on the corrosion of high strength concrete with silica fume subjected to 15% concentration of sulphuric acid, hydrochloric acid and lactic acid. Silica fume were used to replace 8% and 15% of the cement, by weight. The results showed that partial replacement of cement with silica fume had no effect on lactic acid resistance, improved the hydrochloric acid resistance and worsened the sulphuric acid attack. Sulphuric acid attack resulted in concrete disintegration at an almost constant rate, the hydrochloric attack rate was reduced with time, whereas the lactic acid attack resulted leaching of corrosion products, at a slower rate under stagnant condition.
Rijal, R, Samali, B, Shrestha, R, Gerber, G & Crews, K 1970, 'Dynamic performance of timber flooring systems', From Materials to Structures: Advancement through Innovation - Proceedings Of The 22nd Australasian Conference on the Mechanics of Structures and Materials, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 1065-1070.
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This paper presents the modal parameters of a LVL timber flooring system with overall dimensions of 8.4Ã1.8m acquired from its finite element (FE) model. The FE model of the floor was created by joining three identical models of a timber floor module (beam) side by side rigidly. The overall length of each floor module was 8.4m and width of top flange was 0.6 m. The individual modules were tested under application of impact load using modal hammer under identical pin-roller boundary conditions. The calibrated FE model of the module was extended to model the flooring system. The behaviour of the floor is assessed based on the modal parameters. Results from the FE model will be correlated with results from experimental tests to be conducted in near future on the floor with the given dimensions at University of Technology Sydney.
Rujikiatkamjorn, C, Indraratna, B & Fatahi, B 1970, 'Numerical prediction of unsaturated ground behavior influenced by vegetation and vacuum consolidation', 5th Asia-Pacific Conference on Unsaturated Soils 2012, Asia-Pacific Conference on Unsaturated Soils Theory and Practice, Kasetsart University, Thailand, pp. 701-706.
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Bioengineering including native vegetation is an ancient method of improving the stability of slopes. In modern railway engineering, this technique is re-captured for increasing the soil stiffness and shear strength of subgrade beneath rail tracks. Currently this practice has become increasingly popular in Australia for stabilising railway corridors built over expansive clays and compressive soft soils. This paper looks at the stabilisation role by suction generated by both the natural vegetation and the artificial vacuum application using the numerical analysis. For demonstrating the role of native vegetation, a mathematical model for the rate of root water uptake was incorporated in the analysis. The soil moisture content distribution and the soil marric suction profile adjacent to the tree were numerically captured based on the general effective stress theory of unsaturated soil. For vacuum application, the equivalent plane strain theory was employed to simulate radial consolidation and artificially applied suction. The performance of both techniques on track constructed on soft formation was discussed and compared in terms of settlement and associated pore pressure.
Sadeghi Hokmabadi, A, Fatahi, B, Far, H & Samali, B 1970, 'Effects of soil-pile-structure interaction on seismic response of moment resisting buildings on soft soil', 3rd International Conference on New Developments in Soil Mechanics and Geotechnical Engineering, International Conference on Soil Mechanics and Geotechnical Engineering, Near East University Press, Turkey, Turkey, pp. 377-385.
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Dynamic response of structures sitting on soft soils is influenced by the soil properties, and the response is significantly different to the fixed base condition owing to the interaction between the ground and the structure, In order to study this effect, a fifteen storey moment resisting building frame, representing a conventional type of regular mid-rise building frame, resting ,on soil type Ee according to Australian Earthquake action code with the shear wave velocity equal to 150 mls is adopted. The numerical analysis using FLAC2D software is carried out for three different cases, namely: (1) fixed-base structure representing the situation excluding the soil-structure interaction (SSI); (2) structure supported by shallow foundation on soft soil; and (3) structure supported by pile foundation in soft soil. Benchmark earthquakes including the 1995 Kobe, the 1994 Northridge, the 1968 Hachinohe, and the 1940 EI Centro earthquakes are adopted. Results indicate that considering soil-structure interaction in both cases with shallow and pile fouudations is vital, and the conventional desigu procedure excluding soil-structure interaction is not adequate to guarantee the structural safety for the moment resisting buildings resting on the soft soil.
Satsangi, R, Vessalas, K & Russell, S 1970, 'Assessment of bottom ash use as fine aggregate replacement in concrete', From Materials to Structures: Advancement Through Innovation - Proceedings of the 22nd Australasian Conference on the Mechanics of Structures and Materials, ACMSM 2012, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, SYDNEY, AUSTRALIA, pp. 1183-1186.
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Concrete is the most common construction material used worldwide. Fine aggregate constitutes approximately 25% of the total volume of concrete. Currently, most fine aggregate used in concrete consists of naturally occurring sands, which are sourced from sand quarries. In the future, Sydney will face a sand shortage, with most quarries becoming exhausted. This will likely lead to increased demand in using sands hauled from longer distances, adversely impacting the environment. This project investigates the feasibility of using bottom ash (BA) as a novel sand replacement in concrete. BA is defined as a by-product of coal burning power stations. The BAs used in this study were sourced from 3 different power stations in NSW to assess the practicality of using BA for replacement of sand in concrete. Compared to control concrete, Bayswater BA concretes showed improved performance at 20% replacement of sand content with higher compressive strength and lower drying shrinkage. © 2013 Taylor & Francis Group.
Shearman, L, Gerber, C & Crews, K 1970, 'Stressed cross-laminated-timber for bridge applications', From Materials to Structures: Advancement through Innovation - PROCEEDINGS OF THE 22ND AUSTRALASIAN CONFERENCE ON THE MECHANICS OF STRUCTURES AND MATERIALS, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 1071-1076.
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An increasing focus on environmentally suitable construction solutions, EngineeredWood Products (EWPs) are growing in popularity. This project aims is to investigate an EWP decking system applicable for the refurbishment of existing bridges and for new structures. Stress Laminated Timber (SLT) systems have been widely implemented worldwide and provide a structurally sound decking solution for bridges. This technology forms the background of the current research whereby the structural feasibility of stressing Cross Laminated Timber (CLT) â in substitution to solid wood boards â with Laminated Veneer Lumber (LVL) webs in T beam and cellular systems is investigated. This research focuses on serviceability testing to identify the systemâs behaviour under line loading to characterise the system stiffness and pad loading to understand the load distribution ability of the system. The project includes a review of SLT technology and discusses the application CLT in stressed bridge decking. Laboratory tests have been completed and analysed comprehensively. This analysis includes the system stiffness and load distribution. Recommendations for system improvement and further research are also put forward.
Shrestha, R, Mak, J & Crews, K 1970, 'Experimental investigation on epoxy bonded shear connection for timber-concrete composites', World Conference on Timber Engineering 2012, WCTE 2012, World Conference on Timber Engineering, Rijun Shrestha, James Mak, Keith Crews, Auckland, New Zealand, pp. 466-472.
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This paper presents the results of an experimental investigation on epoxy bonded shear connections for timber-concrete composites, with and without mechanical fasteners. The results of the tests showed that connections with high stiffness and strength, comparable to that of notch type connections, could be achieved by using epoxy for bonding timber and concrete. Addition of a mechanical fastener to the epoxy bonded connection had the advantage of delaying the failure of the connection and thereby avoiding brittle failure mode associated with epoxy bonded connections. The coach screw also facilitated in maintaining good contact between concrete and LVL. Observation of the failed specimens showed that failure in all connections was concentrated either in the LVL or concrete close to the interface and no interface failure was observed.
Stuart, BH, Thomas, P & Hunt, AM 1970, 'The characterisation of ochres used in Australian Aboriginal paintings', 2nd International Congress - Chemistry for Cultural Heritage Abstracts, 2nd International Congress - Chemistry for Cultural Heritage.
Subhani, M, Li, J & Samali, B 1970, 'Behaviour of stress wave propagation in utility timber pole', From Materials to Structures: Advancement through Innovation - PROCEEDINGS OF THE 22ND AUSTRALASIAN CONFERENCE ON THE MECHANICS OF STRUCTURES AND MATERIALS, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, SYDNEY, AUSTRALIA, pp. 1077-1082.
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Non-destructive testing has been used for many years to evaluate the in situ condition of timber piles. Longitudinal impact is usually applied on the top of piles to induce longitudinal wave to detect faults in piles due to the fact that the longitudinalwave has less dispersive nature at lowfrequency. On the other hand,when it comes to evaluation of poles in situ, it is different as poles are partly embedded in soil and it is more practical to produce bending waves, as the top of the pole is not easily accessible. However, bending wave is known for its highly dispersive nature; especially in the low frequency range which is usually induced in low strain integrity testing. As bending wave can be considered as a hybrid of longitudinal and shear waves, it will be helpful, if it could detect the component of these twowaves separately.To do so, components of displacements or accelerations along radial and longitudinal directions need to be determined. By applying Fast Fourier Transform (FFT) on the signals, the dominant frequencies can be obtained. It has been found that, the longitudinal component decreases along radial direction which indicates the presence of bending wave component and this finding allows to the application of ContinuousWavelet Transform (CWT) on the longitudinal component of wave signals in order to obtain phase velocity. Phase velocities at different frequencies are then determined to draw the dispersive curve and compare with analytical phase velocity curve. The dispersion curve matched well with the analytical curve.
Sullivan, CE, Stuart, BH & Thomas, P 1970, 'An investigation of the preservation of burial goods produced from modern materials', 6th European Academy of Forensic Science Conference Abstracts, 6th European Academy of Forensic Science Conference.
Tabatabaiefar, HR, Fatahi, B & Samali, B 1970, 'Effects of soil dynamic properties and bedrock depth on seismic response of building frames incorporation soil-structure interaction', 5th Asia-Pacific Conference on Unsaturated Soils 2012, Asian-Pacific conferences on unsaturated soils, Kasetsart University, Pattaya, Thailand, pp. 504-510.
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In this study, a ten storey moment resisting building frame, resting on a shallow foundation, is selected in conjunction with three soil types with the shear wave velocities less than 600m/s, representing classes Ce, De and Ee, according to AS 1170.4. Different bedrock depths including 10m, 20m, and 30 m are employed in the numerical modelling using finite difference software FLAC 2D. Fully nonlinear dynamic analysis under influence of different earthquake records is conducted, and the results of the three different cases are compared and discussed. The results indicate that the dynamic properties of the subsoil such as shear wave velocity as well as bedrock depth play significant roles in seismic response of the building frames under the influence of soil-structure interaction. As the shear wave velocity of the subsoil decreases and bedrock depth increases, lateral deflections and inter-storey drifts of the structures increase. The mentioned effects can change the performance level of the structures from life safe to near collapse or total collapse. Therefore, the conventional design procedure excluding SSI is no longer adequate to guarantee the structural safety for the building frames resting on soft soil deposits.
Tao, M, Wu, C & Li, X 1970, 'Numerical simulation of unloading process of rocks under high initial stress', ISRM Regional Symposium - 7th Asian Rock Mechanics Symposium, ARMS 2012, pp. 253-261.
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The object of this study is to investigate the unloading failure mechanism of hard rocks in the unloading process. A commercial finite element program LS-DYNA was employed to simulate the rock unloading process. The implicit and explicit methods were performed in sequence to simulate the static initialization-dynamic unloading process of rocks. The numerical results indicated that the rock failure can be induced by releasing of the initial stress, and the previous result of the equivalent initial stress release rate (EISRR) theory based on the 1D stress state is not suitable for 3D stress state. In 3D stress state, a new definition of equivalent strain energy release rate (ESERR) was introduced. The further study indicated that the ESERR can characterize the effect of different confining stresses and different unloading path on rock unloading. A significant finding is that the ESERR can quantitatively describe the characteristics of the unloading process under 3D stress state. This finding indicated that in practical underground excavation engineering, dynamically controlling the ESERR can be used to increase excavation potential of rocks and minimize the needed external excavation energy by using the initial energy.’
Tennakoon, N, Indraratna, B, Nimbalkar, S & Rujikiatkamjorn, C 1970, 'Deformation and Degradation of Clay fouled Ballast Subjected to Monotonic Loading', Proceedings of the International Conference on Ground Improvement & Ground Control, International Conference on Ground Improvement & Ground Control, Research Publishing Services.
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Thomas, D, Ding, GK & Crews, KI 1970, 'Multi-Storey Residential Timber Buildings in Australia: Where is the education', Australasian Universities Building Educators Association (AUBEA), 37th AUBEA International Conference: Proceedings, Australian Universities Building Education Association Annual Conference, The University of New South Wales, Sydney, Australia, pp. 163-170.
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There is a growing interest in the construction of medium rise residential timber buildings internationally. A number of developers in Australia are seeking to complete the first structural timber residential building over four storeys high. The most widely advertised is a 10-storey timber apartment building in planning for the city of Melbourne, to be built to 'Passive House' standards. Amongst a number of challenges that face Australian building companies adopting this innovative construction technique is the lack of skill and experience in construction professionals that have worked on medium rise timber structural buildings. The current practice for the design of structural frame for residential buildings over four storeys high is in the use reinforced concrete and steel. Previous studies have revealed that although construction professionals have an interest in innovative timber structures their preference for working with concrete and steel is based on previous education and familiarity with the materials. Preliminary investigations have revealed that Australian university degree courses in Architecture, Civil/Construction Engineering and Construction Project Management receive little or no education on engineered timber medium rise residential buildings construction. This paper aims at investigating the current uptake, demand, opportunities and barriers for timber use in residential buildings. This paper presents the results of semi-structured interviews with Australian construction professionals and tertiary education providers and highlights the challenges they face in adapting to innovations entering their industry. Finally this paper presents strategies on how these two sectors can work cooperatively to incorporate multi storey timber building education into universities across Australia.
Thomas, D, Ding, GK & Crews, KI 1970, 'Sustainable timber use in the Australian housing market: Are consumers willing to pay the price?', Proceedings of the XXXVIII IAHS World Congress: Visions for the future of housing : Mega cities, IAHS World Congress on Housing Science, Istanbul Technical University, Istanbul, Turkey, pp. 1076-1082.
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A large proportion of traditional Australian homes contained timber floors and timber exterior cladding until the advent of the standard concrete slab/brick veneer house. Up to 95% of new homes are built by project home companies and the majority of these contain an external envelope consisting of concrete flooring, clay brick walls and concrete tile or steel sheet roofing. This design is currently driven by consumer's expectation of low cost, durable homes that are completed within restricted time limits. There is now a price premium on bespoke housing projects that differ materially or otherwise from a limited set of designs offered by project home firms. The adoption of concrete and brick homes originated from a perceived advantage of longevity, low maintenance and thermal comfort. Innovation in wood treatments, wood protection and insulation have provided solutions to these issues so that timber is now a viable option with added benefits such as environmental sustainability and erection speed. Australian consumers have a growing awareness and desire to live in a way that is sustainable and are making choices that reflect this attitude. This has been demonstrated through the high adoption rate of recent government-supported schemes such as subsidized insulation and solar panel installation. This paper aims at investigating homeowner's perception of timber as a sustainable building product, the desire of homeowners to use sustainable building products, and the willingness of homeowners to pay a premium to live sustainably. This paper highlights Australian homeowners reluctance to use the most sustainable building materials even when they are willing to pay for a more environmentally sustainable home. This paper presents the results of a questionnaire survey to homeowners in the city of Sydney, New South Wales, Australia and some strategies on how to increase the use of timber in new housing projects in Australia.
Xiang Luo, Xiang Thomas Ren, Yan Li & Jianguo Jack Wang 1970, 'Mobile surveying system for road assets monitoring and management', 2012 7th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2012 7th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Singapore, pp. 1688-1693.
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Road assets' condition has a critical impact on road safety and efficiency. It is a big challenge to accurately and efficiently monitor and manage road assets. This paper proposes a mobile surveying system that is cost efficient and robust to acquire and manage road assets information in highly dynamic environments like highways and urban streets, where the data collection has previously been laborious and even dangerous for the staff performing the survey. Equipped with laser measurement systems, camera, proprioceptive sensors and novel sensor fusion algorithms; the proposed system can survey and manage road assets expeditiously. Laser sensors measure surroundings with range and remission data. Range data is processed to build up 3D model of surveyed objectives with position and attitude information from proprioceptive sensors. Remission data is used for extracting traffic lanes and signs on the roads. Each traffic lane's clearance of structures, like bridges and tunnels, is calculated and marked on the 3D model, and compared with the signs captured by the camera. Road surface condition is measured by both inertial and laser sensors. Any abnormal circumstance detected is reported automatically. The surveying results are presented in a user friendly interface and saved as videos for convenient data management. Experimental results of a prototype system demonstrate its performance for road assets monitoring and management. © 2012 IEEE.
Yan, N, Li, J, Dackermann, U & Samali, B 1970, 'Numerical and experimental investigations of stress wave propagation in utility poles under soil influence', From materials to structures: Advancement through innovation, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Sydney, Australia, pp. 593-598.
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Over the past decades, different types of non-destructive testing (NDT) methods have been developed for the condition assessment of timber structures. Stress wave methods, which are based on stress wave propagation theory, are considered to be simple and cost-effective tools for identifying damage as well as embedment length of timber poles/piles. However, due to the lack of understanding on wave propagation in such structures, especially under the influence of surroundings such as soil, these methods encounter difficulties in producing reliable results. In this paper, an investigation was carried out on the wave propagation behaviour in utility timber poles under consideration of soil effects. The commercial finite element (FE) analysis software ANSYS was used to simulate stress wave propagation in a timber utility pole under the influence of soil. In order to verify the numerical findings, laboratory testing was also conducted in dual course with the numerical modelling.
Zabihi, Z, Samali, B, Shrestha, R, Gerber, C & Crews, K 1970, 'Serviceability and ultimate performance of long span timber floor modules', World Conference on Timber Engineering 2012, WCTE 2012, Curran association, Auckland, New Zealand, pp. 378-385.
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The advent of engineered wood products (EVVP's) such as LVL and glulam as well as a new generation of adhesives has provided the means to fabricate large section, long spanning structural members with similar structural properties to that of steel or concrete, which have attracted a great deal of renewed interest in long-span timber constructions. This paper presents the results of the tests conducted on LVL timber floor modules, with overall lengths of 6.3 m and 8.4 m (6m and 8m clear span, respectively), under serviceability load, as well as the results of 3 destructive tests conducted on 8m clear span LVL timber modules. All serviceability and destructive tests were conducted under four point bending load, and the performance of these long span 'timber only' floor modules arc investigated for serviceability and ultimate limit states. The linear characteristics of the modules, the composite behaviour of the section as well as the failure modes of the system are assessed and discussed in this paper.
Zeng, J, Guo, Y, Zhu, J, Li, Y & Li, J 1970, 'Magnetic Hysteresis Properties Measurement for Magneto-Rheological Elastomer', the 13th International Conference on Electrorheological Fluids and Magnetorheological Suspensions: Book of Abstracts, Gazi University, Ankara, Turkey, pp. 1-2.
Zhuang, Y, Hong, G & Wang, J 1970, 'Preliminary investigation to combustion in a SI engine with direct ethanol injection and port gasoline injection (EDI+GPI)', Proceedings of the 18th Australasian Fluid Mechanics Conference, AFMC 2012, Australasian Fluid Mechanics Conference, Australasian Fluid Mechanics Society, Launceston, Tasmania, Australia, pp. 1-4.
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Ethanol fuel, as a renewable fuel can play an important role in addressing the critical issue of energy resources if it is used in a proper way. Ethanol direct injection plus gasoline port injection (EDI+GPI) is such a new way to enable substantial improvement in engine efficiency and emission reduction in spark ignition engines. This paper reports our preliminary investigation to the combustion and emissions in this new dual fuel injection system. Experiments were conducted on a single-cylinder spark ignition engine equipped with EDI+GPI. In the experiments, the ethanol/gasoline volumetric percentage (EVP) was varied from 0% (gasoline fuel only) to 71%. Mass burnt fraction and indicated mean effective pressure (IMEP) were calculated from the measured cylinder pressure for analysing the combustion process. The variance of IMEP, reduced with the increased EVP, showed that the combustion stability was improved by the direct injection of ethanol fuel. The effect of EVP on initial, early and major combustion time periods showed that ethanol fuel's higher combustion velocity and low ignition energy might contribute to accelerating the flame propagating, shortening the combustion periods and reducing the combustion temperature when EVP was less than 48%. However further increase of EVP when it was over 48% resulted in a negative effect on combustion which might be caused by the ethanol fuel's over cooling effect. Hydrocarbon and carbon monoxide emission increased and nitric oxide emission decreased with the increase of EVP.
Zhuang, Y, Wang, J & Hong, G 1970, 'A single cylinder research engine for investigating combustion of direct ethanol injection and port gasoline injection', Proceedings of the 18th Australasian Fluid Mechanics Conference, AFMC 2012, Australasian Fluid Mechanics Conference, Australasian Fluid Mechanics Society, Launceston, Tasmania, Australia, pp. 1-4.
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Ethanol has been used as a renewable fuel in internal combustion (IC) engines. However, the existing method of blending gasoline and ethanol fuels does not take the advantages of ethanol fuel, such as its high Octane number and great latent heat of vaporization, to increase the engine compression ratio and consequently the thermal efficiency. Ethanol direct injection plus gasoline port injection (EDI+GPI) is a new technology for using ethanol fuel more effectively and efficiently in IC engine. To experimentally investigate this new technique, a research engine has been developed by modifying a commercial product representing the cylinder capacity of a down sized passenger car engine. In the development of this research engine, two major tasks were addressed: the two separate fuel systems and the electronic control unit (ECU). The operation of both fuel systems including the high pressure pump and the common rail fuel pressure are electronically controlled. The ECU also controls the throttle position and fuel flow rates in an open loop to provide the flexibility of manual adjustments of engine speed, load and lambda. Sample results are reported to show that the developed engine system has met the basic requirements of experiments in this investigation.