Publications

Dang, LC, Dang, CC & Khabbaz, MH 2019, 'A Parametric Study of Deep Mixing Columns and Fibre Reinforced Load Transfer Platform Supported Embankments' in New Prospects in Geotechnical Engineering Aspects of Civil Infrastructures, Springer, Cham, pp. 179-194.
View/Download from: Publisher's site
View description>>

The ground improvement technique using deep cement mixing (DCM) columns combined with geosynthetic reinforced traditional angular layer as a load transfer platform supported embankments has recently been adopted widely in construction of roads, railways, and highways over soft soils. This modification technique provides a practical and efficient measure for such infrastructure construction projects as it brings significant savings in construction costs and construction time. In this numerical study, a novel ground modification technique utilising fibre reinforced load transfer platform (FRLTP) and DCM columns supported embankment constructed on top of multilayers of soft soils is proposed and investigated based on the finite element method incorporated in PLAXIS. A series of numerical analyses was firstly carried out on the full geometry of a DCM columns supported (CS) embankment reinforced without or with an FRLTP in a two-dimensional plane strain condition. The main objective of this analysis is to examine the effectiveness of the FRLTP inclusion into the CS embankment system in terms of maximum settlement and lateral displacement. Subsequently, an extensive parametric study was conducted to further investigate the influence of the FRLTP thickness on the performance of the CS embankment by comparing the maximum and differential settlements, and the lateral displacement. The numerical results reveal that the embankment with FRLTP inclusion can effectively enhance the total settlement and the lateral displacement of the embankment. The findings of the extensive parametric study reveal that the platform thickness has significant influence on the embankment behavior, especially in improving the total and differential settlements, the rigidity and stability of the embankment, and the more load transfer from the embankment to DCM columns. Meanwhile it significantly minimises the lateral displacement and the embankment loads transferred to soft foundation soils.

Ding, GKC 2019, 'Emissions' in Tam, VWY & Khoa, NL (eds), Sustainable construction technologies: Life cycle assessment, Butterworth-Heinemann, Oxford, UK, pp. 263-297.
View/Download from: UTS OPUS
View description>>

The construction industry contributes significantly to environmental pollution. Construction, including the building sector, first began to recognize the impact of its activities on sustainable development in the 1990s. The building sector, on the one hand, has a strong influence on economics and the society itself and thus enhancing the standard of living and well-being of humankind. On the other, construction is often associated with the impairment of the environment. The main focus in achieving the goal of sustainable construction is to improve building performance so as to reduce energy use and emissions. The use of sustainable technologies and environmentally friendly materials are incorporated in the design and construction of buildings. Life cycle assessment has been developed as a systematic approach to assessing emissions in buildings and has provided information with regards to developing strategies and improving processes to reduce emissions. Therefore the use and selection of sustainable technologies and improved manufacturing processes in the production of building materials play an important role in reducing energy use and emissions in buildings. This chapter focuses on reviewing the current-state-of-the-art of emissions in buildings, international collaboration for emission reductions and the advancement of technologies and material to reduce emissions in buildings.

Li, Y & Li, J 2019, 'Development of smart base isolation system for civil structures utilising magnetorheological elastomer' in Magneto-Rheological Materials and Their Applications, Institution of Engineering & Technology.

Wang, J, Zhang, G, Wang, H, Ouyang, Q, Zheng, J, Li, Y & Li, Z 2019, 'Use of magnetorheological shock absorber for impact loading mitigation with individually controllable coils' in Magneto-Rheological Materials and Their Applications, Institution of Engineering & Technology.

Biradar, J, Banerjee, S, Shankar, R, Ghosh, P, Mukherjee, S & Fatahi, B 2019, 'Response of square anchor plates embedded in reinforced soft clay subjected to cyclic loading', GEOMECHANICS AND ENGINEERING, vol. 17, no. 2, pp. 165-173.
View/Download from: Publisher's site

Bryce, T, Far, H & Gardner, A 2019, 'Barriers to Career Advancement for Female Engineers in Australia’s Civil Construction Industry and Recommended Solutions', Australian Journal of Civil Engineering, vol. 17, no. 1, pp. 1-10.
View/Download from: UTS OPUS or Publisher's site
View description>>

This study explores the challenges that have emerged from the outdated and inflexible workplace culture of the civil construction industry, and how it is affecting female engineers and women in other functional site roles. The study primarily explores issues such as the strong culture of long work hours, the perception of staff who pursue work-life balance, and the perception of part time and flexible working options within the industry. The study was conducted over three phases where members of the industry answered questionnaires on the workplace issues listed above. The first phase aimed to document a female perspective on the construction workplace culture while the second phase focused on the perceptions of the same respondents regarding the industry’s attitude to work-life balance and whether any of the aspects of workplace culture has discouraged them from staying in the industry. The final phase included men and women in management and employer roles to determine their views on part time and flexible working options within the industry. The results of the study are presented and discussed before recommendations are offered for contractor organisations, their employers and staff. The recommendations have been addressed in a way that a gradual culture change can be accepted and acted on throughout the entire workplace.

Chenari, RJ, Fatahi, B, Ghoreishi, M & Taleb, A 2019, 'Physical and numerical modelling of the inherent variability of shear strength in soil mechanics', GEOMECHANICS AND ENGINEERING, vol. 17, no. 1, pp. 31-45.
View/Download from: Publisher's site

Dackermann, U, Smith, WA, Alamdari, MM, Li, J & Randall, RB 2019, 'Cepstrum-based damage identification in structures with progressive damage', STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL, vol. 18, no. 1, pp. 87-102.
View/Download from: UTS OPUS or Publisher's site

Dang, LC, Dang, CC & Khabbaz, H 2019, 'Modelling of columns and fibre reinforced load transfer platform supported embankments', Proceedings of the Institution of Civil Engineers - Ground Improvement.
View/Download from: UTS OPUS or Publisher's site
View description>>

This study proposes a novel ground modification technique utilising fibre reinforced load transfer platform (FRLTP) and deep cement mixing (DCM) columns supported (CS) embankment constructed over soft soils. An equivalent two-dimensional finite element model was developed to simulate the full geometry of a CS embankment reinforced without or with an FRLTP. A series of numerical analyses was firstly conducted on the proposed model for different improvement depths to assess the effectiveness of the introduction of FRLTP into the CS embankment system in terms of total and differential settlements, stress transfer mechanism and lateral displacement with depth. Subsequently, another extensive parametric study was conducted to further investigate the influence of the FRLTP key parameters including elastic deformation modulus, shear strength properties, and tensile strength on the embankment performance during construction and consolidation time. The numerical results show that the embankment with FRLTP can effectively diminish the total settlement and the lateral deformation of the embankment, meanwhile improve the stress concentration ratio and the embankment stability to a great extent. The findings of the extensive parametric study indicate that the FRLTP shear strength properties appear to be the most influence factors to be considered in the design procedure of a target CS-FRLTP-embankment system.

De Carvalho Gomes, S, Zhou, JL, Li, W & Long, G 2019, 'Progress in manufacture and properties of construction materials incorporating water treatment sludge: A review', Resources, Conservation and Recycling, pp. 148-159.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2019 Elsevier B.V. Water treatment sludge (WTS) management is a growing global problem for water treatment plants (WTPs) and governments. Considering the scarcity of raw materials in many parts of the planet and unique properties of WTS, extensive research has been conducted on the application of WTS in the production of construction materials such as roof tiles, bricks, lightweight aggregates, cement, concrete and geopolymers. This paper critically reviews the progress in the application of WTS in construction materials, by synthesizing results from recent studies. Research findings have revealed that incorporation of ≤10% alum-based sludge in ceramic bricks is satisfactory with a small reduction of mechanical performance. Using the iron-based sludge, the bricks presented better mechanical strength than the reference clay-bricks. Concerning WTS application in concrete, 5% replacement of cement or sand by WTS was considered as the ideal value for the application in a variety of structural and non-structural concrete without adverse effect on concrete mechanical performance. Furthermore, this paper discusses sludge-amended concrete in terms of durability, potential leaching of toxic elements and cost, and suggests topics for future research on the sustainable management of WTS.

Dong, W, Li, W, Long, G, Tao, Z, Li, J & Wang, K 2019, 'Electrical resistivity and mechanical properties of cementitious composite incorporating conductive rubber fibres', SMART MATERIALS AND STRUCTURES, vol. 28, no. 8.
View/Download from: Publisher's site

Dong, W, Li, W, Shen, L & Sheng, D 2019, 'Piezoresistive behaviours of carbon black cement-based sensors with layer-distributed conductive rubber fibres', Materials and Design, vol. 182.
View/Download from: Publisher's site
View description>>

© 2019 Conductive rubber fibres filled carbon black (CB)/cementitious composites were developed to achieve the cement-based sensors with excellent piezoresistivity in this study. Ameliorations on the conductivity and piezoresistive sensitivity of CB filled composites were mainly explored with conductive rubber fibres embedded. Their compressive strengths were investigated to evaluate the practical application possibility. The results indicated that the composites with CB content <4.0 wt% possessed acceptable compressive strengths. In terms of conductivity and piezoresistivity, both conductivity and piezoresistivity of composites filled with 0.5 wt% CB increased with the rubber content, and their gauge factor raised to 91 when embedded with 80 rubber fibres (1.27 vol%). Moreover, phenomenon of “piezoresistive percolation” was observed by sharp fractional changes of resistivity for the composites filled with 1.0 wt% CB, where existed highest gauge factor reaching 482 when embedded with same rubber fibres. However, because of the excellent conductivity of 2.0 wt% CB filled composites, the gauge factor firstly increased but then slightly decreased around 100 with increase of rubber fibre content. Overall, conductive rubber fibres can significantly improve the piezoresistivity of CB/cementitious composites by the increased gauge factor.

Dong, W, Li, W, Tao, Z & Wang, K 2019, 'Piezoresistive properties of cement-based sensors: Review and perspective', Construction and Building Materials, vol. 203, pp. 146-163.
View/Download from: Publisher's site
View description>>

© 2019 Elsevier Ltd Cement-based sensors are increasingly used in smart concrete to self-sense and monitor the damages and cracks through the measurements of concrete electrical resistivity. The fundamental concepts, key components, manufacturing process, piezoresistivity measurements, and primary applications of cement-based sensors are reviewed in this paper. Various materials, mechanical and environmental factors affecting concrete piezoresistive properties are explicated. Some contradictory results from different studies are reported and discussed. Future perspectives of piezoresistive cement-based sensors are also delineated. The review reveals that there is an optimal conductor content, below which the sensor would perform more like plain concrete with high resistivity and low sensitivity, while excessively higher than which, the dispersion of the conductive phase could become difficult, thus increasing resistivity. The manufacturing process, such as the dispersion method of conductors and curing condition, plays a significant role in conductor distribution, matrix density and pore structure of the sensors, which, together with rheology of the sensor composite, consequently alters the piezoresistive properties of the sensors. In addition to responding to mechanical loading, cement-based piezoresistive sensor also has a great potential for monitoring behaviour of concrete under freeze-thaw cycling. It is expected that this review will provide not only an orientation for new researchers to explore and engage in related studies but also an insight for experienced researchers to perform transformational examinations into cement-based piezoresistive sensors.

Fang, J, Wu, C, Li, J, Liu, Q, Wu, C, Sun, G & Li, Q 2019, 'Phase field fracture in elasto-plastic solids: Variational formulation for multi-surface plasticity and effects of plastic yield surfaces and hardening', International Journal of Mechanical Sciences, vol. 156, pp. 382-396.
View/Download from: Publisher's site
View description>>

The phase field modelling has been extended from brittle fracture to ductile fracture by incorporating plasticity. However, the effects of plastic yield functions and hardening on the fracture behaviour have not been examined systematically to date. The phase field fracture coupled with multi-surface plasticity is formulated in the variational framework for the unified yield criterion, which is able to facilitate the study on different yield surfaces. First, the homogeneous solutions of fracture in elasto-plastic solids are derived analytically for 1D and 2D cases. The results show that a greater hardening modulus would lead to an ascending branch of the stress versus strain curve; and the yield function may significantly affect the stress state and phase field damage. Second, the finite element (FE) technique is implemented for modelling the phase field fracture in elasto-plastic solids, in which the stress update and consistent tangent modular matrix are derived for the unified yield criterion. Finally, three numerical examples are presented to explore the effects of the yield function and material hardening. It is found that the yield function and material hardening could significantly affect the crack propagation and the final fracture pattern. In particular, the Tresca yield function tends to create a straight crack path orthogonal to the first principal stress, while the other yield functions show no sizeable difference in their crack paths.

Fang, J, Wu, C, Rabczuk, T, Wu, C, Ma, C, Sun, G & Li, Q 2019, 'Phase field fracture in elasto-plastic solids: Abaqus implementation and case studies', Theoretical and Applied Fracture Mechanics, vol. 103.
View/Download from: Publisher's site
View description>>

© 2019 Elsevier Ltd Phase field modelling for fracture has been extended from elastic solids to elasto-plastic solids. In this study, we present the implementation procedures of a staggered scheme for phase field fracture of elasto-plastic solids in commercial finite element software Abaqus using subroutines UEL and UMAT. The UMAT is written for the constitutive behaviour of elasto-plastic solids, while the UEL is written for the phase field fracture. The phase field and displacement field are solved separately using the Newton-Raphson iteration method. In each iteration, one field is computed by freezing the other field at the last loading increment. A number of benchmark examples are tested from one single element up to 3D problems. The correctness of the staggered scheme is verified analytically in terms of the stress-strain curve and the evolution of the phase field in the one single element example. In the 2D and 3D problems, the fracture behaviour of elasto-plastic solids can be reproduced in terms of reaction force curve and crack propagation, which exhibit good agreement with the experimental observations and numerical results in literature. Not only can the proposed implementation help attract more academic researchers, but also engineering practitioners to take the advantages of phase field modelling for fracture in elasto-plastic solids. The Abaqus subroutine codes can be downloaded online from Mendeley data repository linked to this work (The link is provided in Supplementary material).

Far, C & Far, H 2019, 'Improving Energy Efficiency of Existing Residential Buildings Using Effective Thermal Retrofit of Building Envelope', Indoor and Built Environment, vol. 28, no. 6, pp. 744-760.
View/Download from: UTS OPUS or Publisher's site
View description>>

Upgrading the energy efficiency of existing buildings is a well-known issue around the globe. Given the very low renewal rate of the building stock, thermal retrofit of the existing buildings seems to be a good solution to improve the environmental performance of the building sector. Several studies have acknowledged the lack of knowledge, experience and best-practice examples as barriers in thermal retrofit of existing buildings. Therefore, this study has focused on developing recommendations on the most effective and feasible retrofitting techniques for existing buildings and performing financial analysis of initial investment vs. return based on the quantitative results of the energy modelling. Thermal comfort modelling software FirstRate5 has been used to simulate the annual heating and cooling energy consumption of nine benchmark buildings through a range of retrofitting techniques. Dwellings of varying construction materials including weatherboard, cavity brick and brick veneer have been simulated to improve accuracy. Examining seven different thermal retrofitting options in this study, it has become apparent that there is significant heating and cooling energy reduction, with payback period of less than three years, by implementing two options of the examined retrofitting cases to existing residential dwellings.

Far, H 2019, 'Advanced Computation Methods for Soil Structure Interaction Analysis of Structures Resting on Soft Soils', International Journal of Geotechnical Engineering, vol. 13, no. 4, pp. 352-359.
View/Download from: UTS OPUS or Publisher's site
View description>>

Adopting the most accurate and realistic modelling technique and computation method for treatment of dynamic soil-structure interaction effects in seismic analysis and design of structures resting on soft soil deposits is one of the most discussed and challenging issues in the field of seismic design and re-qualification of different structures. In this study, a comprehensive critical review has been carried out on available and well-known modelling techniques and computation methods for dynamic soil-structure interaction analysis. Discussing and comparing the advantages and disadvantages of employing each method, in this study, the most precise and reliable modelling technique as well as computation method have been identified and proposed to be employed in studying dynamic soil-structure interaction analysis of structures resting on soft soil deposits.

Far, H 2019, 'Dynamic Behaviour of Unbraced Steel Frames Resting on Soft Ground', Steel Construction, vol. 12, no. 2, pp. 135-140.
View/Download from: UTS OPUS or Publisher's site

Far, H & Far, C 2019, 'Experimental Investigation on Creep Behaviour of Composite Sandwich Panels Constructed from Polystyrene/Cement-Mixed Cores and Thin Cement Sheet Facings', Australian Journal of Structural Engineering, vol. 20, no. 1, pp. 63-73.
View/Download from: UTS OPUS or Publisher's site
View description>>

Composite sandwich panels have gradually become more popular due to their typical benefits including strength, weight, ease of handling, durability, versatility, thermal and acoustic properties. Many researchers are aware of these benefits and have undertaken detailed research and publicised large amounts of scientific papers on composite sandwich panels. With the variety of loads that could possibly be applied to a structure, often the in service life behaviour is significant. Reviewing whether it will function correctly and without excessive deformations is a factor that can sometimes impact the performance. Polystyrene/cement mixed cores and thin cement sheet facings composite sandwich panels are Australian products made of cement-polystyrene beaded mixture encapsulated between two thick cement board sheets. The creep and creep recovery properties of these sandwich panels are relatively unknown. Therefore, in this study, in order to understand the creep and creep recovery behaviour of those sandwich panels, a series of experimental tests have been performed and the outcomes have been explained and discussed. Based on the results of this study, values for immediate recovery, creep recovery and irrecoverable creep strain are determined and proposed. In addition, typical creep and creep recovery design curves have been developed and presented for practical applications in structural engineering.

Far, H & Far, C 2019, 'Timber Portal Frames vs Timber Truss-Based Systems for Residential Buildings', Advances in Civil Engineering, vol. 2019, pp. 1-7.
View/Download from: UTS OPUS or Publisher's site
View description>>

A large number of structures have been built during or after the construction of a house or residential-zoned building, which are not built at the same time and/or integrally with the structural integrity of the residential dwelling. These include carports, pergolas, sheds, and barns. The typical method of constructing these structures is a general timber truss and column system. The aim of this study is to look at the feasibility and economic incentive that may be gained from using a timber portal frame system, similar to the steel or timber portal frames used for larger industrial constructions, over the traditional timber truss and column arrangement. In this study, designs for three cases of timber truss and timber portals were carried out using industry appropriate methods and standards. Using the design information and data gathered through talks with industry professionals, both methods of construction were compared on cost and overall time duration. From the comparison of the truss and portal designs, the use of timber portal frames over timber truss systems proved to have advantage in relation to overall cost and man power involved. This could certainly affect the current attitude towards the construction of small residential buildings in the future.

Fatahi, B 2019, 'Editorial', Proceedings of the Institution of Civil Engineers: Ground Improvement, vol. 172, no. 1, pp. 1-2.
View/Download from: Publisher's site

Gowripalan, N, Cao, J, Sirivivatnanon, V & South, W 2019, 'Accelerated autoclave test for determining alkali silica reaction of concrete', Concrete in Australia, vol. Volume 45, no. No 2, pp. 37-40.
View/Download from: UTS OPUS
View description>>

An ultra accelerated multi-cycle autoclave test has been developed and evaluated for the assessment of expansion caused by alkali silica reaction in concrete.

Gowripalan, N, Nguyen, T, Yang, Y, Li, J & Sirivivatnanon, V 2019, 'Evaluation of elastic modulus reduction due to ASR', Concrete in Australia, vol. Volume 45, no. No 2, pp. 47-52.
View/Download from: UTS OPUS
View description>>

Evaluation of reduction in modulus of elasticity of concrete undergoing alkali silica reaction is carried out using an artificial neural network

Gowripalan, N, Vu, T, De Silva, P, Sirivivatnanon, V & Kidd, P 2019, 'Influence of curing and retarder on early-age properties of powder geopolymer concrete', Concrete in Australia, vol. Volume 45, no. No 2, pp. 41-46.
View/Download from: UTS OPUS
View description>>

The effect of different curing conditions and the addition of a retarder on flow characteristics, setting time and strength development of a powder form of geopolymer is reported.

Gu, X, Yu, Y, Li, Y, Li, J, Askari, M & Samali, B 2019, 'Experimental study of semi-active magnetorheological elastomer base isolation system using optimal neuro fuzzy logic control', Mechanical Systems and Signal Processing, vol. 119, pp. 380-398.
View/Download from: UTS OPUS or Publisher's site
View description>>

In this paper, a “smart” base isolation strategy is proposed in this study utilising a semi-active magnetorheological elastomer (MRE) isolator whose stiffness can be controlled in real-time and reversible fashion. By modulating the applied current, the horizontal stiffness of the MRE isolator can be controlled and thus the control action can be generated for the isolated structure. To overcome the inherent nonlinearity and hysteresis of the MRE isolator, radial basis function neural network based fuzzy logic control (RBF-NFLC) was developed due to its inherent robustness and capability in coping with uncertainties. The NFLC was optimised by a non-dominated sorting genetic algorithm type II (NSGA-II) for better suited fuzzy control rules as well as most appropriate parameters for the membership functions. To evaluate the effectiveness of the proposed smart base isolation system, four scenarios are tested under various historical earthquake excitations, i.e. bare building with no isolation, passive isolated structure, MRE isolated structure with Bang-Bang control, MRE isolated structure with proposed NFLC. A three-storey shear building model was adopted as the testing bed. Through the testing results, limited performance of passive isolation system was revealed. In contrast, the adaptability of the proposed isolation strategy was demonstrated and it is proven that the smart MRE base isolation system is able to provide satisfactory protection for both structural and non-structural elements of the system over a wide range of hazard dynamic loadings.

He, LX, Wu, C & Li, J 2019, 'Post-earthquake evaluation of damage and residual performance of UHPSFRC piers based on nonlinear model updating', Journal of Sound and Vibration, vol. 448, pp. 53-72.
View/Download from: Publisher's site
View description>>

© 2019 Elsevier Ltd This paper presents an innovative approach for damage and residual performance evaluation of ultra-high performance steel fiber reinforced concrete (UHPSFRC) piers after earthquakes utilizing low-level vibration tests. A nonlinear fiber section element model is constructed in OpenSees to simulate the hysteretic behavior of a UHPSFRC bridge pier. Experimental data from a UHPSFRC column is utilized to verify the accuracy of the nonlinear numerical model. Based on the nonlinear fiber section element model, a new technique of nonlinear finite element model updating involving two updating stages is developed. This new method is designed to incorporate the maximum and minimum strains of section fibers as the updating parameters. By forming the objective function from the modal information, the damage parameters related to the nonlinear material model can be updated by solving the constrained optimization problem. To validate the efficiency of this updating approach, it has been applied to a numerically simulated UHPSFRC pier. With using the updated nonlinear finite element model, the residual axial loading capacity and post-seismic performance of the UHPSFRC pier are examined. The numerical results indicate that the updated nonlinear finite element model can be used not only to assess the current damage state of the UHPSFRC pier but also to predict its future performance after an earthquake. Finally, the noise effect on the proposed method is also investigated. The results reveal that the post-earthquake evaluation approach for UHPSFRC piers based on this study's updating algorithm is robust to noise.

Hoang, VT, Phung, MD, Dinh, TH & Ha, QP 2019, 'System Architecture for Real-Time Surface Inspection Using Multiple UAVs', IEEE Systems Journal, pp. 1-12.
View/Download from: UTS OPUS or Publisher's site

Hu, Y, Tang, Z, Li, W, Li, Y & Tam, VWY 2019, 'Physical-mechanical properties of fly ash/GGBFS geopolymer composites with recycled aggregates', Construction and Building Materials, vol. 226, pp. 139-151.
View/Download from: Publisher's site
View description>>

© 2019 Elsevier Ltd The properties of fly ash and ground granulated blast furnace slag (GGBFS) combination based geopolymer composites containing recycled aggregate are investigated in this study, which obtained from construction and demolition wastes. The effects of recycled aggregate replacement and GGBFS inclusion on the physical and mechanical properties of geopolymer composites were investigated in this study. The scanning electron microscopic (SEM) were conducted to provide a thorough insight into the characterization of microstructures. The results reveal that using recycled aggregate has an insignificant impact on workability and setting time, while it causes a reduction in physical and mechanical properties. The inclusion of GGBFS reduces workability and setting time. However, improved physical and mechanical properties can be achieved in the geopolymer composites after the incorporation of GGBFS, and this effect is more prominent in the geopolymer composites containing recycled aggregates. The water absorption and sorptivity exhibit a strong correlation with the volume of permeable voids of geopolymer composites. Besides, very good relationships were established between the compressive strength and other mechanical properties, and these relationships fitted reasonably well with the other predictions.

Huang, L, Liu, Z, Wu, C & Liang, J 2019, 'The scattering of plane P, SV waves by twin lining tunnels with imperfect interfaces embedded in an elastic half-space', Tunnelling and Underground Space Technology, vol. 85, pp. 319-330.
View/Download from: Publisher's site
View description>>

© 2018 Elsevier Ltd A viscous-slip interface model is employed to simulate the contact between the tunnels lining and the surrounding rock, and the scattering of P, SV waves by twin shallowly buried lining tunnels is investigated with the indirect boundary integral equation method (IBIEM). The amplification effect of the dynamic stress concentration of the lining and the surface displacement near the tunnels is examined. It is evident that the slipping-stiffness coefficient and viscosity coefficient at the lining-surrounding rock interface have a significant influence on the dynamic stress distribution and the nearby surface displacement response of the lining tunnel, while the influence characteristics strongly depend on the incident wave type, frequency and angle. Under the incidence of low frequency wave, as a whole, with the increase of the sliding stiffness, the hoop stress increases gradually for plane P and SV waves; while in the resonance frequency (the incident wave frequency is consistent with the natural frequency of the soil column above the tunnels), specially for high-frequency band, the dynamic stress concentration effect is more significant for smaller sliding stiffness. With the increase of viscosity coefficient, the dynamic stress concentration factor inside the lining gradually decreases. Also, the tunnels with viscous-slip interfaces have a more significant amplification effect on the nearby surface displacement amplitude. Moreover, the hoop stress of the twin tunnels may be obviously larger than that of single tunnel in most cases. The dynamic analysis of the underground structure under the actual strong dynamic loading should consider the influence of the slip effect between the lining and surrounding rock interface.

Jahandari, S, Saberian, M, Tao, Z, Mojtahedi, SF, Li, J, Ghasemi, M, Rezvani, SS & Li, W 2019, 'Effects of saturation degrees, freezing-thawing, and curing on geotechnical properties of lime and lime-cement concretes', Cold Regions Science and Technology, vol. 160, pp. 242-251.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2019 Elsevier B.V. There are very limited researches carried out to investigate the influence of saturation degrees, freezing-thawing, and curing times on geotechnical properties of lime concrete (LC) and lime-cement concrete (LCC) due to the capillary action and changes in groundwater table. Subsequently, the primary goal of this research is to investigate the influence of these parameters on mechanical properties of LC and LCC using unconfined compression tests, namely uniaxial compressive strength (UCS), stress-strain behavior, deformability index (I D ), secant modulus (E S ), failure strain, bulk modulus (K), resilient modulus (M R ), brittleness index (I B ), and shear modulus (G). At first, the mechanical and chemical characteristics of the utilized materials were measured. Then, samples were made with an optimal amount of cement, lime, coarse-grained soil, fine-grained soil, and water. The samples were then exposed to saturation points extending from 0 to 100% after 14, 28, 45 and 60 curing days. Then, to consider the effect of amount of saturation on the mechanical properties, UCS tests were performed on some of the samples. Other LCC specimens were exposed to freezing-thawing conditions to consider the effect of this phenomenon on the mechanical properties as well. The results of more than 250 UCS tests demonstrated that the curing times significantly affected the strength of LC and LCC specimens. Moreover, it is not ideal and logical to utilize LC and LC columns at a profundity underneath or near the groundwater level, though it is reasonable to adopt LCC and LCC columns at a profundity beneath or near the groundwater level because of the immaterial effect of degrees of saturation on LCC. In addition, this study showed that extending the curing period and diminishing the saturation degree would increase the strength and mechanical properties of the LCC specimens. The results of freezing-thawing demonstrated a negligible increase in the strength of t...

Jamshidi Chenari, R, Alaie, R & Fatahi, B 2019, 'Constrained Compression Models for Tire-Derived Aggregate-Sand Mixtures Using Enhanced Large Scale Oedometer Testing Apparatus', Geotechnical and Geological Engineering.
View/Download from: Publisher's site
View description>>

© 2018, Springer Nature Switzerland AG. Tire derived aggregates have recently been in wide use both in industry and engineering applications depending on the size and the application sought. Five different contents of tire derived aggregates (TDA) were mixed with sand thoroughly to ensure homogeneity. A series of large scale oedometer experiments were conducted to investigate the compressibility properties of the mixtures. Tire shreds content, TDA aspect ratio, skeletal relative density and overburden pressure are studied parameters. Constrained deformation modulus and coefficient of earth pressure at rest are measured parameters. All tests were conducted at seven overburden pressure levels. It was concluded that deformability of TDA-sand mixture increases with soft inclusion. Overburden pressure and skeletal relative density are also important parameters which render more rigidity and less lateral earth pressure coefficient accordingly. TDA size or aspect ratio was shown to have minor effect at least for the constrained strain conditions encountered in current study. An EPR-based parametric study and also sensitivity analyses based on cosine amplitude method revealed quantitative evaluation of the relative importance of each input parameter in varying deformation and lateral earth pressure coefficient as the outputs.

Khabbaz, H, Gibson, R & Fatahi, B 2019, 'Effect of Constructing Twin Tunnels under a Building Supported by Pile Foundations in the Sydney Central Business District', Underground Space.
View/Download from: Publisher's site

La, HM, Dinh, TH, Pham, NH, Ha, QP & Pham, AQ 2019, 'Automated robotic monitoring and inspection of steel structures and bridges', Robotica, vol. 37, no. 5, pp. 947-967.
View/Download from: UTS OPUS or Publisher's site
View description>>

Copyright © Cambridge University Press 2018 This paper presents visual and 3D structure inspection for steel structures and bridges using a developed climbing robot. The robot can move freely on a steel surface, carry sensors, collect data and then send to the ground station in real-time for monitoring as well as further processing. Steel surface image stitching and 3D map building are conducted to provide a current condition of the structure. Also, a computer vision-based method is implemented to detect surface defects on stitched images. The effectiveness of the climbing robot's inspection is tested in multiple circumstances to ensure strong steel adhesion and successful data collection. The detection method was also successfully evaluated on various test images, where steel cracks could be automatically identified, without the requirement of some heuristic reasoning.

Li, CY, Chen, SJ, Li, WG, Li, XY, Ruan, D & Duan, WH 2019, 'Dynamic increased reinforcing effect of graphene oxide on cementitious nanocomposite', Construction and Building Materials, vol. 206, pp. 694-702.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2019 The reinforcing effect of graphene oxide on cementitious materials under high strain rate remains largely unknown. Existing studies on microfiber reinforced cementitious composites showed that the dynamic increase factor (DIF) decreases due to these fibres. This study reports that the reinforcing effect of graphene oxide nanosheets can, in contrast, increase with strain rate. Tensile splitting and compression tests were conducted under both static and dynamic loadings. High strain rate, up to 1700 s −1 , is achieved using a split Hopkinson pressure bar apparatus. It is found that the DIF of graphene oxide nanocomposite only increase when the DIF is higher than a threshold which is about 780 and 30 s −1 for compression and tensile test respectively. The increased of DIF was correlated with the speed of crack development and pull-out of the graphene oxide nanosheets. Also, the pull-out or fracture of graphene oxide on fragmented sand was also found a possible contributing factor to the increased DIF. The findings of this study indicate the future potential of atomic-thin nanosheets for materials under extreme impact and blast loading.

Li, Y & Li, J 2019, 'Overview of the development of smart base isolation system featuring magnetorheological elastomer', Smart structures and systems, vol. 24, no. 1, pp. 37-37.
View/Download from: Publisher's site

Liang, X, Wu, C, Yang, Y & Li, Z 2019, 'Experimental study on ultra-high performance concrete with high fire resistance under simultaneous effect of elevated temperature and impact loading', Cement and Concrete Composites, vol. 98, pp. 29-38.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2019 Fire is a big risk to buildings and structures, posing a great threat to human lives. In this study, a newly developed ultra-high performance concrete (UHPC) was investigated experimentally. Quasi-static compression tests were conducted after the UHPC was first exposed to a high temperature, i.e. 200, 400, 600, 800 or 1000 °C, and then cooled down to room temperature, while dynamic tests were carried out under combined effect of a high temperature, i.e. 200, 400, 600, or 800 °C, and impact loading. The dynamic tests were done both at high temperatures and after cooling down and comparisons were made between these two scenarios. Based on the tests on this UHPC, mechanical and physical characteristics under the combined effect were studied. Besides, explosive spalling was analysed. It was interesting to find polypropylene (PP) fibre could play a negative role in preventing explosive spalling between 320 and 380 °C.

Lin, X, Far, H & Saleh, A 2019, 'Structural Behaviour and Mechanical Properties of Welded Steel I-Girders with Corrugated Webs', International Journal of Steel Structures, vol. 19, no. 4, pp. 1342-1352.
View/Download from: UTS OPUS or Publisher's site
View description>>

Steel I girders with corrugated webs are appropriate alternatives for normal flat-web girders in steel structures since they provide lighter and smaller beam features in steel design. Based on the existing literature, the corrugated web beams (CWBs) provide many advantages for structural applications. In this study, a series of numerical analyses have been performed in order to investigate the structural behaviour of steel I girders with corrugated web profile and to compare their mechanical performance with normal welded beams. Theory of Ultimate Limit State design has been adopted in accordance with AS4100 (1998) along with considering geometric and material non-linearity in the numerical analyses in SAP2000. Comparing the results of the numerical investigation, merits of using corrugated welded beams (CWBs) over normal welded beams (WBs) have become apparent. Moreover, investigations regarding force-displacement relationship and buckling analysis of the webs were carried out and presented to further validate the advantages of using corrugated web beams. CWBs have been used in some parts of Australia without detailed information about their mechanical properties. Thus, based on the outcomes of this study, CWB table for dimensions and cross sectional properties has been developed and proposed for practical applications.

Ling, Y, Wang, K, Li, W, Shi, G & Lu, P 2019, 'Effect of slag on the mechanical properties and bond strength of fly ash-based engineered geopolymer composites', Composites Part B: Engineering, vol. 164, pp. 747-757.
View/Download from: Publisher's site
View description>>

© 2019 Recently, the concept of engineered cementitious composites (ECCs) has been extended to the creation of engineered geopolymer composites (EGCs). Although showing similar mechanical characteristics (e. g., strain hardening and multiple cracking) to conventional ECC, the strength of existing EGC is generally low, and this sometimes restrains its applications. In the present study, a low-calcium (Class F) fly ash-based, polyvinyl alcohol (PVA) fiber reinforced EGC was developed and further modified by a ground-granulated blast-furnace slag (slag). The slag was used to replace the fly ash at content of 0%, 10%, 20%, and 30% (by weight). The effects of the slag on the mechanical properties (e.g., compressive strength, modulus of elasticity, uniaxial tensile behavior, flexural bending strength, and pullout bond strength) of the EGCs were investigated. The results revealed that all EGCs studied exhibited a strain/deflection hardening behavior under tension/flexure, and all slag replacements for fly ash enhanced strength-related properties but reduced ductility-related properties of the EGCs. The EGC mix with 20% slag replacement for fly ash (FA-20%S) had 102.3 MPa compressive strength, 6.8 MPa tensile strength, and 6.2 MPa bond strength, while the EGC mix with no slag (FA-0%S) had 72.6 MPa compressive strength, 4.7 MPa tensile strength, and 3.5 MPa bond strength at 28 days. These strength enhancements were mainly attributed to the improved density of the EGC matrix and the bond between the matrix and fiber. There are close relationships between the bond strength and other strengths, especially the tensile and flexural strengths, of the EGCs.

Liu, J, Wu, C, Li, C, Dong, W, Su, Y, Li, J, Cui, N, Zeng, F, Dai, L, Meng, Q & Pang, J 2019, 'Blast testing of high performance geopolymer composite walls reinforced with steel wire mesh and aluminium foam', CONSTRUCTION AND BUILDING MATERIALS, vol. 197, pp. 533-547.
View/Download from: UTS OPUS or Publisher's site

Liu, J, Wu, C, Li, J, Fang, J, Su, Y & Shao, R 2019, 'Ceramic balls protected ultra-high performance concrete structure against projectile impact-A numerical study', INTERNATIONAL JOURNAL OF IMPACT ENGINEERING, vol. 125, pp. 143-162.
View/Download from: UTS OPUS or Publisher's site

Liu, Z, Huang, L, Liang, J & Wu, C 2019, 'A three-dimensional indirect boundary integral equation method for modeling elastic wave scattering in a layered half-space', International Journal of Solids and Structures, vol. 169, pp. 81-94.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2019 A new indirect boundary integral equation method (IBIEM)is proposed in this study to solve three-dimensional (3-D)elastic wave scattering by heterogeneities in a multi-layered half-space, employing Green's function of distributed loads on equivalent circular elements, thus avoiding the element discretization on layer interfaces. The proposed method enables the fictitious loads to be directly distributed on the surfaces of scatterer and the weak singularity to be tackled by analytical integration. Also, the radiation condition in the semi-infinite layered medium can be satisfied accurately, and the memory requirements can also be greatly reduced, especially for a large number of layers or gradient medium. The numerical accuracy was verified through comparisons with existing results and the numerical convergence was also confirmed. The results clearly demonstrate the simplicity and effectiveness of the method, and also reveals the complicated scattering characteristics in a layered half-space that are dominated by the resonant properties of the layered medium.

Liu, Z, Zhang, H, Cheng, A, Wu, C & Yang, G 2019, 'Seismic Interaction between a Lined Tunnel and a Hill under Plane SV Waves by IBEM', International Journal of Structural Stability and Dynamics, vol. 19, no. 2.
View/Download from: Publisher's site
View description>>

© 2019 World Scientific Publishing Company. This paper investigates the dynamic interaction between a lined tunnel and a hill under plane SV waves using the indirect boundary element method (IBEM), with the displacement and stress characteristics of the system presented in frequency domain. The IBEM has several unique advantages such as reducing calculation dimension, automatically satisfying the infinite radiation condition, etc. The numerical results indicated that the dynamic response of the tunnel-hill system is strongly dependent on incident wave characteristics, geometrical and material properties of the lined tunnel, as well as the topography of the hill. For a dimension ratio between the hill and tunnel of less than 10.0, the lined tunnel has large amplification or deamplification effect on the dynamic response of the hill. Correspondingly, the hill also greatly amplifies the displacement and stress concentration of the tunnel especially in the lower-frequency range, due to the complicated interference effect among the reflected waves and diffracted waves induced by the tunnel and hill. Also demonstrated is that the displacement and stress amplitude spectrums highly depend on the incident frequency and the space location, and there exist multiple peaks and troughs in the spectrum curve with the peaks usually appearing in the low-frequency range. Thus, for the seismic safety assessment of a hill slope or hill tunnel in practice, the dynamic interaction within the tunnel-hill system should be taken into consideration.

Lu, ZH, Li, H, Li, W, Zhao, YG, Tang, Z & Sun, Z 2019, 'Shear behavior degradation and failure pattern of reinforced concrete beam with chloride-induced stirrup corrosion', Advances in Structural Engineering.
View/Download from: Publisher's site
View description>>

© The Author(s) 2019. Reinforcement corrosion exhibits an adverse effect on the shear strength of reinforced concrete structures. In order to investigate the effects of chloride-induced corrosion of reinforcing steel on the shear behavior and failure pattern of reinforced concrete beams, a total of 24 reinforced concrete beams with different concrete strength grades and arrangements of stirrups were fabricated, among which 22 beams were subjected to accelerated corrosion to achieve different degrees of reinforcement corrosion. The failure pattern, crack propagation, load–displacement response, and ultimate strength of these beams were investigated under a standard four-point loading test in this study. Extensive comparative analysis was conducted to investigate the effects of the concrete strength, shear span-to-depth ratio, and stirrup type on the shear behavior of the corroded reinforced concrete beams. The results show that increasing the stirrup yielding strength is more effective in improving the shear strength of corroded reinforced concrete beams than that of concrete compressive strength. In terms of three types of stirrups, the shear strength of the beams with deformed HRB-335 is least sensitive to stirrup corrosion, followed by the beams with smooth HPB-235 and the beams with deformed HRB-400. The effect of the different stirrups on the shear strength depends on the corrosion degree of stirrup and shear span-to-depth ratio of the beam. The predicted results of shear strength of corroded reinforced concrete beams by a proposed analytical model are well consistent with the experimental results.

Lu, ZH, Lun, PY, Li, W, Luo, Z, Li, Y & Liu, P 2019, 'Empirical model of corrosion rate for steel reinforced concrete structures in chloride-laden environments', Advances in Structural Engineering, vol. 22, no. 1, pp. 223-239.
View/Download from: UTS OPUS or Publisher's site
View description>>

© The Author(s) 2018. The corrosion rate of reinforcing steel is an important factor to determine the corrosion propagation of reinforced concrete structures in the chloride-laden environments. Since the corrosion rate of reinforcing steel is affected by several coupled parameters, the efficient prediction of which remains challenging. In this study, a total of 156 experimental data on corrosion rate from the literature were collected and compared. Seven empirical models for predicting the corrosion rate were reviewed and investigated using the collected experimental data. Based on the investigations, a new empirical model is proposed for predicting the corrosion rate in corrosion-affected reinforced concrete structures considering parameters including concrete resistivity, temperature, relative humidity, corrosion duration and concrete chloride content. The comparison between the experimental data and those predicted using the new empirical model demonstrates that the new model gives a good prediction of the corrosion rate. Furthermore, the uncertainty and probability characteristics of these empirical models are also investigated. It is found that the probability distributions of the model errors can be described as lognormal, normal, Weibull or Gumbel distributions. As a result, the new empirical model can provide an efficient prediction of the corrosion rate of reinforcing steel, and the model error analysis results can be utilized for reliability-based service life prediction of reinforced concrete structures under chloride-laden environments.

Luo, Z, Li, W, Tam, VWY, Xiao, J & Shah, SP 2019, 'Current progress on nanotechnology application in recycled aggregate concrete', Journal of Sustainable Cement-Based Materials.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. As a very promising sustainable construction material, recycled aggregate concrete (RAC) has become a hot research topic and attracted wide attention. Although many investigations have been conducted, it is still a great challenge to product RAC with satisfactory and stable performance for practical engineering application. In recent years, nanotechnology has been introduced to RAC research and displayed distinct advantages over many traditional methods. This article is devoted to reviewing the current research on nanotechnology application in RAC, including nanoengineering and nanoscience. The corresponding results involving microstructure characteristics, mechanical properties, workability, and durability were summarized and discussed. It has been found that nanoscience has promoted better understanding of microstructure and various internal mechanism of RAC, while nanoengineering has helped RAC achieve dense microstructure, improved mechanical properties and durability. However, further efforts are required to realize the potential of nanotechnology and to bring breakthroughs in research and application of RAC.

Ly, BT & Far, H 2019, 'Investigation on Properties of Coarse Reclaimed Aggregates and Their Effects on Concrete Strength and Workability', Structural Concrete.
View/Download from: UTS OPUS or Publisher's site
View description>>

Fresh concrete waste is constantly generated in concrete batch plants during the production of ready-mix concrete and this waste is generally dumped in landfills. Natural aggregates are a finite resource and therefore there is a need to recycle this fresh concrete waste. An on-site reclaimer can recycle fresh concrete waste to produce reclaimed aggregate and eliminate the need to dump fresh concrete waste in landfills. This study investigates the properties of coarse reclaimed aggregates sampled from an Australian concrete batch plant. It was observed that the particle size distribution was highly varied while particle density and water absorption were similar to their parent aggregate. It was also found that concrete containing coarse reclaimed aggregates exhibited a higher workability and lower compressive strength than concrete containing natural coarse aggregates. Utilisation of coarse reclaimed aggregates in concrete application is a viable option, however more research will need to be conducted in this area.

Meng, Q, Wu, C, Su, Y, Li, J, Liu, J & Pang, J 2019, 'A study of steel wire mesh reinforced high performance geopolymer concrete slabs under blast loading', Journal of Cleaner Production, vol. 210, pp. 1150-1163.
View/Download from: UTS OPUS or Publisher's site
View description>>

In this study, a novel green construction material, high performance alkali-activated geopolymer concrete is introduced. Both numerically and experimentally investigations were conducted on a new type of structural slabs made of steel wire mesh reinforced geopolymer concrete against close-in ground surface explosion. Steel rebar reinforced conventional concrete slabs are also studied to compare the results. The experimental investigation was conducted to study the slab damage mechanism. It is found that the steel wire mesh reinforced geopolymer concrete slab showed less damage and fragmentation under 50 kg Trinitrotoluene (TNT) blast load within 3 m, 5 m and 7 m distances as compared to the C30 concrete slab. Numerical analysis was then conducted to further investigate the slab dynamic responses. Combining the steel wire mesh reinforcement with geopolymer concrete can help increase the blast resistance capacity leading to promising and environmental friendly structural protective design.

Meng, Q, Wu, C, Su, Y, Li, J, Liu, J & Pang, J 2019, 'Experimental and numerical investigation of blast resistant capacity of high performance geopolymer concrete panels', Composites Part B: Engineering, vol. 171, pp. 9-19.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2019 Elsevier Ltd In this study, the mechanical properties of a novel high performance alkali-activated geopolymer concrete under both static and dynamic loads were studied. The ground granulated blast-furnace slag powder (GGBS) and silica fume were used to manufacture this geopolymer concrete. Slabs that cast with this geopolymer concrete and steel wire mesh reinforcement were tested under close-in TNT explosion. The steel rebar reinforced C30 concrete slabs were tested as a control group. It is found that the steel wire mesh reinforced geopolymer concrete slabs achieved a more uniform strain distribution, which means a better structural performance against blast loadings as compared to the conventional C30 concrete slab under the same blast loads. The numerical investigation was then conducted to elaborate the test results.

Moghaddam, F, Sirivivatnanon, V & Vessalas, K 2019, 'The effect of fly ash fineness on heat of hydration, microstructure, flow and compressive strength of blended cement pastes', Case Studies in Construction Materials, vol. 10.
View/Download from: Publisher's site
View description>>

© 2019 In this paper, an experimental study on the effect of fly ash fineness on the heat of hydration, microstructure, flow and compressive strength of blended cement pastes was carried out and evaluated against control cement paste. Fly ashes with different fineness: classified fly ash, run-of-station fly ash and grounded run-of-station fly ash; with a median particle size of 17.4, 11.3 and 5.7 μm, respectively, from the same power station source in Australia were used to partially replace Portland cement at 20% and 40% by weight of cement using a fixed water-to-binder ratio of 0.40. Results of this study showed that the cumulative heat of hydration of blended cement paste decreased as fly ash content in blended cement paste was increased. For a given cement replacement level, blended cement paste containing finer fly ash released more heat of hydration when compared to coarser fly ash. Moreover, increasing the fineness of fly ash resulted in a higher consumption of calcium hydroxide at 7 and 28 days reflecting pozzolanic reactivity and, thus, a denser microstructure than blended pastes containing coarser fly ash as revealed by the X-ray diffraction (XRD), scanning electron microscopy (SEM) and compressive strength results. In addition, the incorporation of fly ash in the blended pastes led to the introduction of an additional hydration peak in the heat evolution curve possibly due to the late activation of fly ash by calcium hydroxide renewing the C 3 A reaction and converting ettringite to monosulfate. The flow of the freshly blended cement pastes was also found to improve slightly with increasing fineness of the fly ash. In addition, the hardened blended cement pastes containing 20% ground run-of-station fly ash showed comparable compressive strength with the control cement pastes at both 7 and 28 days mainly due to the higher fineness of the ground run-of-station fly ash and increased reactivity compared to coarser grade fly ash.

Nguyen, H, Khabbaz, H & Fatahi, B 2019, 'A numerical comparison of installation sequences of plain concrete rigid inclusions', Computers and Geotechnics, vol. 105, pp. 1-26.
View/Download from: UTS OPUS
View description>>

Soil displacement induced when installing controlled modulus columns (CMC) as ground reinforcement could affect the columns installed close by. Realising numerical analyses may provide useful insights, this paper describes a numerical approach to investigate how groups of CMC installed in different sequences could affect columns installed previously. Coupled consolidation analyses in large strain mode and incorporating soil-CMC interaction were carried out using the three-dimensional finite difference software package FLAC3D. The CMCs were modelled using advanced non-linear Hoek-Brown material with a tensile yield criterion while soils with a typical profile were characterised using the modified Cam Clay and the elastic-perfectly plastic material with a Mohr-Coulomb yield criterion. Where possible, the predicted responses of ground surrounding the CMCs were compared to a number of existing analytical methods. Predictions revealed that lateral soil movement and soil heave near existing CMCs induced by installing new CMCs towards the existing CMCs were approximately 15% and 25% greater than corresponding predictions when a reverse installation sequence was adopted. The maximum excess pore water pressures, induced near existing columns due to installing new columns towards the existing ones, were almost twice more than those caused by the reverse sequence of installation. Moreover, the predicted bending moments generated in the existing columns induced by installing new columns towards the existing CMCs were almost 22% greater than the corresponding values when the reverse installation sequence was adopted. This shows the importance of selecting an appropriate installation sequence in the CMC construction process as well as considering the initial stress field and bending moments in the surrounding soil and CMCs, respectively when designing embankments on improved soft soils.

Nimbalkar, SS, Punetha, P, Basack, S & Mirzababaei, M 2019, 'Piles subjected to torsional cyclic load: Numerical analysis', Frontiers in Built Environment, vol. 5.
View/Download from: Publisher's site
View description>>

© 2019 Nimbalkar, Punetha, Basack and Mirzababaei. Pile foundations supporting large structures (such as high-rise buildings, oil drilling platforms, bridges etc). are often subjected to eccentric lateral load (in addition to the vertical loads) due to the action of wind, waves, high speed traffic, and ship impacts etc. The eccentric lateral load, which is usually cyclic (repetitive) in nature, induces torsion in the pile foundation. This paper presents a numerical model based on boundary element approach to study the performance of a single pile subjected to the torsional cyclic load. The model is initially validated by comparing it with the experimental data available from the literature. Thereafter, the model has been utilized to conduct a parametric study to understand the influence of the torsional cyclic loading parameters on the axial pile capacity. The results indicated that the model is able to capture the degradation in the axial pile capacity due to the torsional cyclic loading with a reasonable accuracy. Moreover, the parametric study showed that the frequency, amplitude and number of cycles play a significant role in the torsional cyclic response of the pile. The present study is essential for the development of design guidelines for pile foundations subjected to torsional cyclic load.

Rao, P, Zhao, L, Chen, Q & Nimbalkar, S 2019, 'Three-dimensional limit analysis of slopes reinforced with piles in soils exhibiting heterogeneity and anisotropy in cohesion', Soil Dynamics and Earthquake Engineering, vol. 121, pp. 194-199.
View/Download from: Publisher's site
View description>>

© 2019 Elsevier Ltd Reinforcement of slopes by placing piles is one of the most common and effective techniques. Most of existing studies are limited to homogeneous and isotropic slopes, while in practice, the soil in the slope often exhibits heterogeneous and anisotropic characteristics. To address these issues, an innovative approach is introduced in this Technical Note to evaluate the stability of heterogeneous and anisotropic slopes incorporating the effect of anti-slide piles. Employing a three-dimensional upper-bound limit analysis, safety factor adopting the strength reduction technique is utilized herewith. The effects of soil heterogeneity and anisotropy with reference to cohesion on the optimal pile location and the slope stability in both cohesive-frictional and purely cohesive soils are investigated. The results amply demonstrate that the proposed limit analysis is appropriate for the stability assessment of reinforced slopes in heterogeneous and anisotropic soils. The safety factor increases with increase in heterogeneous factor and decrease in anisotropic factor. The optimal pile location is irrespective of these two factors, which should be carefully considered in engineering design.

Rao, P, Zhao, L, Chen, Q & Nimbalkar, S 2019, 'Three-dimensional slope stability analysis incorporating coupled effects of pile reinforcement and reservoir drawdown', International Journal of Geomechanics, vol. 19, no. 4.
View/Download from: Publisher's site
View description>>

© 2019 American Society of Civil Engineers. In pile-reinforced dams and bank slopes, the antislide effect of piles and drawdown of reservoirs are two aspects that could significantly affect the slope stability. However, existing studies have incorporated these two factors separately, albeit not in tandem. Moreover, stability assessment of these earth structures is usually performed ignoring the three-dimensional (3D) effect. To address these issues, the kinematic approach of limit analysis is adopted in this technical note for evaluating slope stability based on the 3D rotational failure mechanism. In addition, the coupled effects of pile reinforcement and water drawdown are considered. The analysis is performed for four types of drawdown cases. The results demonstrate that the optimal pile location undergoes significant change during the external drawdown process, while the effect of the declining water level on slope stability follows the similar pattern for varying pile locations.

Rasouli, H & Fatahi, B 2019, 'A novel cushioned piled raft foundation to protect buildings subjected to normal fault rupture', COMPUTERS AND GEOTECHNICS, vol. 106, pp. 228-248.
View/Download from: UTS OPUS or Publisher's site

Sarikaya, A & Erkmen, R 2019, 'A plastic-damage model for concrete under compression', International Journal of Mechanical Sciences, vol. 150, pp. 584-593.
View/Download from: UTS OPUS or Publisher's site
View description>>

A phenomenological model for plain concrete under compression is formulated within the framework of the coupled elastoplastic-damage theory. Phenomenological elastoplastic-damage models have been widely used for concrete because of their capability of representing both the permanent inelastic deformations and the degra- dation of material moduli beyond the elastic range. The essential contribution introduced in this paper is the proposed partitioning of the strain tensor within the coupled elastoplastic-damage framework which simplifies the selection of the failure surface and the potential function. Proposed partitioning permits the use of single failure criterion and single potential surface that are effective for both damage and plasticity models during inelastic deformations. Therefore, the coupled elastoplastic-damage model can be easily calibrated to fit the ob- served concrete behaviour based on well-established non-associated plasticity rules for concrete. The proposed approach also simplifies the numerical procedure by eliminating iterations that is required to equilibrate the stresses in plastic and damage components of the model. The numerical implementation is explained, and the results predicted by the model are compared with experimental data provided in the literature.

Shakor, P, Nejadi, S & Paul, G 2019, 'A Study into the Effect of Different Nozzles Shapes and Fibre-Reinforcement in 3D Printed Mortar', Materials, vol. 12, no. 10.
View/Download from: UTS OPUS or Publisher's site
View description>>

Recently, 3D printing has become one of themost popular additivemanufacturing technologies. This technology has been utilised to prototype trial and produced components for various applications, such as fashion, food, automotive,medical, and construction. In recent years, automation also has become increasingly prevalent in the construction field. Extrusion printing is the most successful method to print cementitiousmaterials, but it still faces significant challenges, such as pumpability ofmaterials, buildability, consistency in the materials, flowability, and workability. This paper investigates the properties of 3D printed fibre-reinforced cementitious mortar prisms and members in conjunction with automation to achieve the optimum mechanical strength of printed mortar and to obtain suitable flowability and consistent workability for the mixed cementitious mortar during the printing process. This study also considered the necessary trial tests, which are required to check the mechanical properties and behaviour of the proportions of the cementitious mix. Mechanical strength was measured and shown to increase when the samples were printed using fibre-reinforced mortar by means of a caulking gun, compared with the samples that were printed using the same mix delivered by a progressive cavity pump to a 6 degree-of-freedom robot. The flexural strength of the four-printed layer fibre-reinforced mortar was found to be 3.44 0.11MPa and 5.78 0.02MPa for the one-layer. Moreover, the mortar with different types of nozzles by means of caulking is printed and compared. Several experimental tests for the fresh state of the mortar were conducted and are discussed.

Shakor, P, Nejadi, S, Paul, G & Malek, S 2019, 'Review of emerging additive manufacturing technologies in 3D printing of cementitious materials in the construction industry', Frontiers in Built Environment, vol. 4.
View/Download from: Publisher's site
View description>>

Additive manufacturing is a fabrication technology that is rapidly revolutionizing the manufacturing and construction sectors. In this paper, a review of various prototyping technologies for printing cementitious materials and selected 3D printing techniques are presented in detail. Benchmark examples are provided to compare three well-known printing techniques; inkjet printing (binder jetting), selected laser sintering (SLS), and extrusion printing (extrusion based process). A comprehensive search in the literature was conducted to identify various mix designs that could be employed when printing cementitious materials. Aspects of concrete mix design are described, and some new experiments are conducted to analyse the printability of new mixes by the authors. Future research in the area of the rheology of cementitious materials and its relationship with the structural performance of finished concretes are highlighted.

Shakor, P, Nejadi, S, Paul, G & Malekmohammadi, S 2019, 'Review of emerging additive manufacturing technologies in 3D printing of cementitious materials in the construction industry', Frontiers in Built Environment, vol. 4, pp. 1-17.
View/Download from: UTS OPUS or Publisher's site

Shakor, P, Nejadi, S, Paul, G, Sanjayan, J & Nazari, A 2019, 'Mechanical Properties of Cement-Based Materials and Effect of Elevated Temperature on Three-Dimensional (3-D) Printed Mortar Specimens in Inkjet 3-D Printing', ACI Materials Journal, vol. 116, no. 2, pp. 55-67.
View/Download from: UTS OPUS or Publisher's site

Shao, R, Wu, C, Su, Y, Liu, Z, Liu, J & Xu, S 2019, 'Numerical analysis on impact response of ultra-high strength concrete protected with composite materials against steel ogive-nosed projectile penetration', Composite Structures, vol. 220, pp. 861-874.
View/Download from: Publisher's site
View description>>

© 2019 Elsevier Ltd In order to investigate the impact behaviours of ultra-high strength concrete (UHSC) target protected with high-toughness lightweight energy absorption composite materials against the projectile penetration thoroughly, a numerical study using LS-DYNA is conducted at impact velocities between 540 m/s and 810 m/s. The major compositions of FE models are the same as those of experimental specimens which include steel wire mesh reinforced concrete (SWMRC) plates, UHMWPE fibre laminates, aluminium foam sheets and the protected UHSC. Numerical results involving depth of penetration (DOP), impact crater (exfoliated) diameter of SWMRC plates, localized damage and ballistic deviation of the projectiles are obtained and then compared with experimental data, where the numerical results show reasonable agreement with the test results. Based on the validated FE models, the projectile penetration process and the energy evolution between the target and the projectile are studied. In addition, a parametric analysis is conducted to investigate the influence of the arrangement order for present composite materials on DOP and impact resistance of reinforced UHSC target, as well as the ballistic deviation and deformation of the projectile. Results of this study indicate that for the current UHSC target, firstly, the ballistic deviation and projectile deformation are two important factors affecting the impact resistance of the target; secondly, the fibre laminates play a major role in the projectile ballistic deviation and the impact kinetic energy of the projectile is mainly absorbed by the concrete matrix, multilayer steel wire meshes and different densities of foam sheets.

Shao, R, Wu, C, Su, Y, Liu, Z, Liu, J, Chen, G & Xu, S 2019, 'Experimental and numerical investigations of penetration resistance of ultra-high strength concrete protected with ceramic balls subjected to projectile impact', Ceramics International, vol. 45, no. 6, pp. 7961-7975.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2019 Elsevier Ltd and Techna Group S.r.l. Ceramic materials characterized by high hardness, high inherent strength, low density and excellent dimensional stability have been extensively applied in the design of high-performance and lightweight protective structures to resist the high-speed projectile impact. In order to study the anti-penetration capability of ceramic balls protected ultra-high strength concrete (CB-UHSC), high-speed projectile impact tests were conducted at striking velocities of 545 m/s, 679 m/s, and 809 m/s to investigate the impact performance of ceramic balls, projectiles, and the protected UHSC. The experimental results indicated the effectiveness and economy of ceramic balls in resisting the high-speed projectile impact. Numerical studies were then conducted to reproduce the projectile penetration process within CB-UHSC targets with the assistance of LS-DYNA. Based on the validated numerical models, impact resistance and ballistic deviation of projectiles, as well as the energy evolution between projectiles and targets, were further investigated to comprehensively understand the impact performance of this newly designed protective structure under projectile penetration.

Singh, AM & Ha, QP 2019, 'Fast Terminal Sliding Control Application for Second-order Underactuated Systems', International Journal of Control, Automation and Systems, vol. 17, no. 8, pp. 1884-1898.
View/Download from: UTS OPUS or Publisher's site

Stuart, BH, Maynard-Casely, HE, Booth, N, Leung, AE & Thomas, PS 2019, 'Neutron diffraction of deuterated tripalmitin and the influence of shear on its crystallisation', CHEMISTRY AND PHYSICS OF LIPIDS, vol. 221, pp. 108-113.
View/Download from: Publisher's site

Sullivan, C, Thomas, P & Stuart, B 2019, 'An atomic force microscopy investigation of plastic wrapping materials of forensic relevance buried in soil environments', Australian Journal of Forensic Sciences, vol. 51, no. 5, pp. 596-605.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2018 Australian Academy of Forensic Sciences Plastics are one means of disposal of items or remains associated with criminal activity. The surface characteristics of plastic wrapping materials of forensic interest in soil environments have been investigated to determine the environmental factors that have the greatest influence on the degradation process of such polymers. Polyethylene bags and poly(vinyl chloride) sheeting were buried in model environments encompassing different soil types, moisture content, pH and temperature. Atomic force microscopy was used to monitor the changes to the polymer surface at a nanometre level. Over a two-year burial period, the degradation of polyethylene was found to be enhanced by an increased moisture content and an elevated soil pH. The plasticizer content of poly(vinyl chloride) was affected by burial and was observed to leach from the plastic in all environments continually over the burial period. A moist environment was shown to have a more pronounced effect on the removal of plasticizer. A measurement of the surface roughness of plastics using atomic force microscopy has been shown to be sensitive to the burial environment and demonstrates the potential of this technique to measure relatively subtle changes to burial items exposed to different environments.

Sun, Y, Nimbalkar, S & Chen, C 2019, 'Particle breakage of granular materials during sample preparation', JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING, vol. 11, no. 2, pp. 417-422.
View/Download from: Publisher's site

Tan, X, Li, W, Zhao, M & Tam, VWY 2019, 'Numerical discrete-element method investigation on failure process of recycled aggregate concrete', Journal of Materials in Civil Engineering, vol. 31, no. 1.
View/Download from: Publisher's site
View description>>

© 2018 American Society of Civil Engineers. This study numerically investigates the failure processes of recycled aggregate concrete (RAC) and natural aggregate concrete (NAC). A two-dimensional simulation based on a discrete-element method (DEM) is conducted with a universal distinct-element code (UDEC) program. RAC is modeled by a combination of rigid Voronoi blocks cemented to each other using contacts for interfaces. The determination procedure of contact microparameters is analyzed, and a series of microscopic contact parameters in different components of modeled recycled aggregate concrete (MRAC) is calibrated using nanoindentation results. The complete stress-strain curves, fracture process, and failure pattern of numerical model are verified by experimental results, proving its accuracy and validation. The initiation, propagation, and coalescence of microcracks and subsequent nonlinear deformation behaviors of cement mortar, modeled natural aggregate, and recycled aggregate concrete are captured through DEM numerical simulations and compared with digital image correlation (DIC) results. It is found that both the new interfacial transition zone and the old interfacial transition zone are the weak links in RAC, where most microcracks initiate and propagate into the cement mortar region. The failure behaviors of MRAC revealed by both experimental and numerical results can effectively provide insights into the failure mechanism and enhancement of RAC.

Tang, Z, Li, W, Hu, Y, Zhou, JL & Tam, VWY 2019, 'Review on designs and properties of multifunctional alkali-activated materials (AAMs)', CONSTRUCTION AND BUILDING MATERIALS, vol. 200, pp. 474-489.
View/Download from: Publisher's site

Tang, Z, Li, W, Ke, G, Zhou, JL & Tam, VWY 2019, 'Sulfate attack resistance of sustainable concrete incorporating various industrial solid wastes', JOURNAL OF CLEANER PRODUCTION, vol. 218, pp. 810-822.
View/Download from: Publisher's site

Tang, Z, Shan, B, Li, WG, Peng, Q & Xiao, Y 2019, 'Structural behavior of glubam I-joists', Construction and Building Materials, vol. 224, pp. 292-305.
View/Download from: Publisher's site
View description>>

© 2019 Elsevier Ltd Glubam, a new type of engineered bamboo composites, is a promising structural material characterized by outstanding mechanical performance and environmental friendliness. In this study, glubam I-joists, with the spans ranging from 2.4 m to 7.5 m, were prepared and tested to evaluate their structural behavior. The glubam I-joists were lengthened by finger joints, and two kinds of connections were used to connect the web and flanges. Four-point bending tests were conducted to examine the failure modes, load-deflection relationships and load carrying capacity of glubam I-joists. Test results indicated that the dominant failure modes of glubam I-joists included shear failure at the finger joint in the web, bending failure at the finger joint in the bottom flange and lateral buckling. Correspondingly, the load carrying capacity of glubam I-joists was governed by the bending strength, shear capacity and critical bending moment. Glubam I-joists have relatively higher mechanical performance compared with other engineered bamboo or timber I-joists with similar dimension, and the bending capacity of the glubam I-joist with continuous web-to-flange connection meets the requirement specified in Chinese code. Based on the experimental findings and existing methods, theoretical methods were proposed for predicting the stiffness and load carrying capacity of glubam I-joist and were also validated by the test results.

Tao, M, Li, Z, Cao, W, Li, X & Wu, C 2019, 'Stress redistribution of dynamic loading incident with arbitrary waveform through a circular cavity', International Journal for Numerical and Analytical Methods in Geomechanics, vol. 43, no. 6, pp. 1279-1299.
View/Download from: Publisher's site
View description>>

© 2019 John Wiley & Sons, Ltd. In actual geotechnical and civil engineering, dynamic stress concentrations around cavities generated by wave sources widely exist. In this study, based on the complex variable theory and Fourier transform method, the expression of the dynamic stress concentration factor (DSCF) around a circular cavity in infinite homogeneous media subjected to transient waves with arbitrary waveform is obtained. The relationships between both steady-state and transient DSCF and their waveform parameters are investigated quantitatively. The results indicate that a relatively large tensile stress is generated with low Poisson's ratio under steady-state incidence. Under the condition of transient incidence, the position of the wave peak has a minor effect on the DSCF in the case of small wavenumber, but it has a significant effect in the opposite case. It is found that when the wavenumber is high, such as 0.5, the stress response lags behind the stress wave. In addition, the closer the wave peak to the center of the waveform, the greater the potential damage of the transient incidence.

Thang, PN, Fatahi, B & Khabbaz, H 2019, 'Impacts of Drying-Wetting and Loading-Unloading Cycles on Small Strain Shear Modulus of Unsaturated Soils', INTERNATIONAL JOURNAL OF GEOMECHANICS, vol. 19, no. 8.
View/Download from: UTS OPUS or Publisher's site

Thanh, HT, Li, J & Zhang, YX 2019, 'Numerical modelling of the flow of self-consolidating engineered cementitious composites using smoothed particle hydrodynamics', Construction and Building Materials, vol. 211, pp. 109-119.
View/Download from: Publisher's site
View description>>

© 2019 Elsevier Ltd In this paper, a numerical method is developed to simulate the flow of self-consolidating engineered cementitious composites (SC-ECC) which can be described as a non-Newtonian viscous fluid in two dimensions. The Lagrangian form of the Navier-Stockes constitutive equations of the SC-ECC is solved using a mesh-free, weakly compressible smoothed particle hydrodynamics (WCSPH). Flexible synthetic fibres in the SC-ECC are modelled as separate particles in the computational domain, which possess the same continuum properties as mortar particles except for the drag force between two adjacent fibre particles. The numerical model is then validated using slump flow tests, and the numerical results are found to be consistent with the experimental data obtained from the literature. The correlations between the wall-effects, the distance of flow, the casting position with the orientation and the distribution of synthetic fibres are also quantitatively investigated in this work using the proposed method.

Thomas, P, Aldrige, L & Smallwood, A 2019, 'Water in opal – what can it tell us?', InColor Magazine, no. 41, pp. 62-69.
View/Download from: UTS OPUS
View description>>

Opal is a hydrous silica composed of predominantly silicon dioxide and water. The chemical composition of opal is normally described by the general formula SiO2.nH2O. The formula indicates that opal contains water and the value of ‘n’ is variable so the water content is variable and is known to range widely. Such a simple formula hides much of the important characteristics of how water is contained in opal and the variability in the water content and states of water is intricately involved in the formation of opal and may influence properties of the opal as a gemstone. The understanding of the states of water in opal is therefore of importance. The way in which the water is contained provides clues to the mechanisms of formation of opal. The water contained may also be used as a probe to help elucidate the complex microstructure beyond the sphere array structure in which precious opal, in particular, is described. This article will outline the types of water present in opal that displays play-of colour (POC) and how these types have been determined using chemical and physical laboratory characterisation techniques.

Vahedian, A, Shrestha, R & Crews, K 2019, 'Experimental and analytical investigation on CFRP strengthened glulam laminated timber beams: Full-scale experiments', Composites Part B: Engineering, vol. 164, pp. 377-389.
View/Download from: UTS OPUS

Vakhshouri, B & Nejadi, S 2019, 'Empirical models and design codes in prediction of modulus of elasticity of concrete', Frontiers of Structural and Civil Engineering, vol. 13, no. 1, pp. 38-48.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2018, Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature. Modulus of Elasticity (MOE) is a key parameter in reinforced concrete design. It represents the stress-strain relationship in the elastic range and is used in the prediction of concrete structures. Out of range estimation of MOE in the existing codes of practice strongly affect the design and performance of the concrete structures. This study includes: (a) evaluation and comparison of the existing analytical models to estimating the MOE in normal strength concrete, and (b) proposing and verifying a new model. In addition, a wide range of experimental databases and empirical models to estimate the MOE from compressive strength and density of concrete are evaluated to verification of the proposed model. The results show underestimation of MOE of conventional concrete in majority of the existing models. Also, considering the consistency between density and mechanical properties of concrete, the predicted MOE in the models including density effect, are more compatible with the experimental results.

Vakhshouri, B, Nejadi, S & Erkmen, E 2019, 'Advances in numerical analysis of creep effect in time-dependent deflection of light-weight concrete slabs', Mechanics of Advanced Materials and Structures.
View/Download from: Publisher's site
View description>>

© 2018, © 2018 Taylor & Francis Group, LLC. Using a wide range of creep models, the experimental results of long-term deflection of lightweight concrete slabs subjected to two levels of early-age loading are investigated. Different creep models give considerably different estimation of the experimental deflection of slabs. The included factors in each creep model to simulate the experimental creep behavior of the concrete, and loading level on the slabs are the main causes of different results. Among the investigated models, the BP1 and FIBMC-2010 models including the aggregate type and concrete density is shown to be in good agreement with the experimental data in both loading levels.

Vakhshouri, B, Rasiah, SR & Nejadi, S 2019, 'Analytical study of the drying shrinkage in light-weight concrete containing EPS beads', ADVANCES IN CEMENT RESEARCH, vol. 31, no. 7, pp. 308-318.
View/Download from: UTS OPUS or Publisher's site

Wang, D, Wu, C, Huang, W & Zhang, Y 2019, 'Vibration investigation on fluid-structure interaction of AP1000 shield building subjected to multi earthquake excitations', Annals of Nuclear Energy, vol. 126, pp. 312-329.
View/Download from: Publisher's site
View description>>

© 2018 Elsevier Ltd Fluid-structure interaction (FSI) between water and water tank of AP1000 nuclear power plant has always been a hot topic because the gravity water tank plays a key role in protecting structural safety in an emergency such as an earthquake. The main target of this study is to investigate the FSI effect on structural dynamic responses of AP1000 shield building with filled and empty water tanks and to explore the most reasonable height of water level for reducing seismic response under inputs of multi three-direction earthquake excitations. For this purpose, method of nonlinear FSI algorithm of finite element is employed based on ANSYS platform. The numerical procedure is validated by comparison with theoretical calculation and existing experimental results of fluid free vibration and structural seismic responses in the situation of El Centro wave. Based on the validated numerical model, a series of numerical simulations on seven partially-filled models in six natural and one artificial earthquake are carried out and corresponding results, such as peak acceleration & displacement, floor response spectrum and structural base shear, are studied comparatively in details. Discussions of this study show that the partially-filled shield building appears significant FSI effect, which generates great influence on structural dynamic characteristics and responses. Reasonable design of the water level can contribute to reducing structural responses and improving seismic safety.

Wang, D, Wu, C, Zhang, Y & Li, S 2019, 'Study on vertical vibration control of long-span steel footbridge with tuned mass dampers under pedestrian excitation', Journal of Constructional Steel Research, vol. 154, pp. 84-98.
View/Download from: Publisher's site
View description>>

© 2018 Elsevier Ltd This paper aims to study crowd-induced vibration control of long-span steel footbridges with different dynamic characteristics by combining methods of site measurement and numerical simulation. Four kinds of footbridge models with sensitive vertical natural frequencies of easily generating human-bridge resonance under pedestrian loading are designed based on an actual steel footbridge. The numerical models are firstly validated by comparative investigation between the site measurement and the simulation. Detailed study on dynamic responses of the four footbridges with and without controlling systems of tuned mass damper (TMD) and multiple tuned mass damper (MTMD) is then conducted under 13 cases of crowd random excitations, rhythmic running and jumping excitations. Results show that the numerical simulation agrees well with the site measurement data. TMD system is found to be highly efficient in reducing vibration responses only when the excitation frequency is basically consistent with the structural natural frequency, which obviously limits the application of TMD system in footbridges as wider excitation frequency bandwidth is caused by human activities. MTMD system are demonstrated to be with higher vibration absorption robustness appearing predominant and stable capacity of reducing structural vibrations under all the crowd random and rhythmic excitations for the four footbridges.

Wang, D, Wu, C, Zhang, Y, Ding, Z & Chen, W 2019, 'Elastic-plastic behavior of AP1000 nuclear island structure under mainshock-aftershock sequences', ANNALS OF NUCLEAR ENERGY, vol. 123, pp. 1-17.
View/Download from: Publisher's site

Wang, H, Li, Y, Zhang, G & Wang, J 2019, 'Effect of temperature on rheological properties of lithium-based magnetorheological grease', Smart Materials and Structures.
View/Download from: Publisher's site

Wang, W, Wu, C & Liu, Z 2019, 'Compressive behavior of hybrid double-skin tubular columns with ultra-high performance fiber-reinforced concrete (UHPFRC)', ENGINEERING STRUCTURES, vol. 180, pp. 419-441.
View/Download from: UTS OPUS or Publisher's site

Wang, W, Wu, C, Li, J, Liu, Z & Lv, Y 2019, 'Behavior of ultra-high performance fiber-reinforced concrete (UHPFRC) filled steel tubular members under lateral impact loading', International Journal of Impact Engineering, vol. 132.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2019 This study investigates the behavior of ultra-high performance fiber-reinforced concrete (UHPFRC) filled steel tubular (UHPFRCFST) members under lateral impact loading. A total of five specimens were prepared and tested under lateral impact loading. All specimens were 168 mm in diameter and 2000 mm in length. In addition to UHPFRCFST members, normal strength concrete (NSC) filled steel tubular (NSCFST) members were also tested for comparison purpose. Other investigated parameters in this study include the impact energy and the presence of an inner void. The test results show that as compared to the NSCFST members, the UHPFRCFST members exhibit higher lateral impact resistance with higher peak and plateau impact forces, smaller deflection, and less local indentation. With the increase of impact energy, the peak impact force, the impact duration, and the deflection of the UHPFRCFST members are increased, while the plateau impact force is almost kept constant. Moreover, the presence of an inner void does not deteriorate the lateral impact resistance of the UHPFRCFST members. Finite element (FE) model was then developed and validated by the test results in this study. Afterwards, full-range analysis was performed to investigate the damage evolution, sectional bending moment distribution, and the interactions between the steel tube and the concrete during the impact process. Finally, detailed parametric analyses were carried out to investigate the influences of different parameters on the lateral impact behavior of UHPFRCFST members.

Wu, P, Wu, C, Liu, Z & Hao, H 2019, 'Investigation of shear performance of UHPC by direct shear tests', Engineering Structures, vol. 183, pp. 780-790.
View/Download from: Publisher's site
View description>>

© 2019 Elsevier Ltd Ultra-high performance concrete (UHPC) has been applied widely in modern structure construction. The outstanding mechanical properties of UHPC not only enable strong yet slim structural designs but also highlight its potential in protective structural constructions against extreme loads. In this study, the shear transfer behaviors of UHPC are investigated by push-off tests on Z-shaped specimens, investigating the influences of the microsteel fiber volume ratio and stirrup reinforcement ratio on the shear strength, shear slip, and shear crack width of UHPC. The test results indicate that using a microsteel fiber can enhance the shear strength of UHPC specimens. Within a reasonable range of the steel fiber volume ratio (optimum volume ratio ranges from 0% to 2.5% for microsteel fiber), the shear strength and shear slip of UHPC increase significantly, and the shear crack width reduces with an increasing steel fiber volume ratio. Additionally, the ductility, shear strength, and shear slip of UHPC increase significantly, and the shear crack width reduces with increasing stirrup ratio. Finally, the simplified empirical equations for the ultimate shear strengths of UHPC specimens are deduced, and indicate good agreement with the experimental results.

Xu, R & Fatahi, B 2019, 'Novel application of geosynthetics to reduce residual drifts of mid-rise buildings after earthquakes', SOIL DYNAMICS AND EARTHQUAKE ENGINEERING, vol. 116, pp. 331-344.
View/Download from: Publisher's site

Xu, S, Wu, C, Liu, Z & Shao, R 2019, 'Experimental investigation on the cyclic behaviors of ultra-high-performance steel fiber reinforced concrete filled thin-walled steel tubular columns', Thin-Walled Structures, vol. 140, pp. 1-20.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2019 This paper presents an experimental investigation on the cyclic behaviors of ultra-high performance steel fiber reinforced concrete filled thin-walled steel tubular columns under combined axial compression and cyclic lateral displacement loading. The failure modes, hysteretic behaviors, envelop diagrams, ductile performance, stiffness degradation and energy dissipation capacity were analyzed in detail. Notably, the cyclic behaviors of referenced high strength concrete and normal strength concrete filled thin-walled steel tubular columns were also studied to get a better illustration of the cyclic behaviors of ultra-high-performance steel fiber reinforced concrete filled thin-walled steel tubular columns. Furthermore, the effects of steel tube thickness, axial compression ratio, volume ratio of steel fiber and slenderness on the cyclic behaviors of ultra-high-performance steel fiber reinforced concrete filled thin-walled steel tubular columns were also investigated in detail. The test results indicate that the high strength concrete filled thin-walled steel tubular columns represent a poor cyclic behavior. However, replacing high strength concrete with ultra-high performance steel fiber reinforced concrete to infill thin-walled steel tubes can get an excellent cyclic behavior. Moreover, the cyclic behavior of ultra-high performance steel fiber reinforced concrete filled thin-walled steel tubular columns is also much better than that of normal strength concrete filled thin-walled steel tubular columns.

Xue, C, Li, W, Li, J & Wang, K 2019, 'Numerical investigation on interface crack initiation and propagation behaviour of self-healing cementitious materials', Cement and Concrete Research, vol. 122, pp. 1-16.
View/Download from: Publisher's site
View description>>

© 2019 Elsevier Ltd Based on the extended finite element method (XFEM) and cohesive surface (CS) technique, the interface cracks between healing agent and cementitious materials in the self-healing mortar beam under three-point bending are numerically investigated in this study. After obtaining original crack feature using XFEM, a parametric study was conducted to comprehensively discuss effects of the elastic ratio between self-healing agent and cementitious materials, bonding strength and fracture toughness of the self-healing agent-cementitious material interface on crack initiation and propagation. The results reveal that crack initiation seriously degrades stiffness of cementitious materials. Flexible healing agent increases the probability of new crack initiation and healed crack propagation, while stiffer healing agent induces obvious stress concentration around the interface, increasing fracture chance of interfacial zone. The numerical model and methodology developed in this study are useful to investigate the self-healing behaviours and develop high efficient self-healing cementitious materials.

Xue, C, Li, W, Li, J, Tam, VWY & Ye, G 2019, 'A review study on encapsulation-based self-healing for cementitious materials', Structural Concrete, vol. 20, no. 1, pp. 198-212.
View/Download from: Publisher's site
View description>>

© 2018 fib. International Federation for Structural Concrete Encapsulation-based self-healing technology is an effective method for healing the crack-deteriorated cementitious material. Encapsulation-based self-healing initiates by crack occurrence and progresses by chemical reaction of released self-healing agents in the cracks, which are contained in capsules. In this paper, a review has been conducted on various healing agents, encapsulation techniques, as well as experimental approaches, basing on existing substantial studies. Recently, there is no consistent agreement on the effective criteria for evaluating encapsulation-based self-healing and mature solution for increasing the survival ratio of capsules during mixing. However, the polyurethane-based healing agents filled in glass or ceramic tubes are popularly applied for self-healing cementitious materials. Besides, the polymer capsules present promising attractions for engineering application. Mechanical strength and durability are the most widely used self-healing efficiency assessment indexes. On the other hand, nondestructive technique and numerical modeling have also extensively adopted to visualize and evaluate the self-healing behavior of cementitious materials. However, there are still some challenges, which require further investigations, such as behavior of crack propagation, kinetics of healing agent in discrete crack surfaces, effect of inserted capsules on the mechanical properties of self-healed cementitious materials.

Yang, G, Yan, X, Nimbalkar, S & Xu, J 2019, 'Effect of Particle Shape and Confining Pressure on Breakage and Deformation of Artificial Rockfill', International Journal of Geosynthetics and Ground Engineering, vol. 5, no. 2.
View/Download from: Publisher's site
View description>>

© 2019, Springer Nature Switzerland AG. The rockfill exhibits a substantial amount of particle breakage when subjected to higher range of stresses. The deformations of rockfill under such excessive stresses often lead to failure and cannot be ignored. The degree of particle breakage is related to the type of the material as well as the particle shape. Based on this, artificially simulated rockfill materials with three different aggregate shapes (prism, cube, and cylinder) were prepared by cement paste-casting method. Through a series of medium-sized triaxial shear tests, the effects of confining pressure and particle shape on the fracture characteristics of the artificial rockfill and its secant modulus were investigated. The useful relationships between particle sphericity and roundness with deformation modulus and particle breakage rate were proposed.

Yeganeh, N & Fatahi, B 2019, 'Effects of choice of soil constitutive model on seismic performance of moment-resisting frames experiencing foundation rocking subjected to near-field earthquakes', Soil Dynamics and Earthquake Engineering, vol. 121, pp. 442-459.
View/Download from: Publisher's site
View description>>

© 2019 Elsevier Ltd The current study investigated the extent to which the choice of the soil constitutive models can impact the predicted seismic performance of a 20-story reinforced concrete moment-resisting building with a mat foundation considering the Seismic Soil-Structure Interaction (SSSI). Since the soil, in general, is the weakest material, involved in the commonplace geotechnical engineering projects, a soil constitutive model would be able to rule the dynamic response of the system. In this research, the hardening plasticity-based soil constitutive model, named “hyperbolic hardening with hysteretic damping” in conjunction with the two simple, conventional soil models, namely, the isotropic elastic with hysteretic damping model, and elastic-perfectly plastic Mohr-Coulomb with hysteretic damping model, were invoked in the three-dimensional coupled soil-structure numerical simulations using FLAC3D software. The direct method of analysis was used for analyzing the soil-foundation-structure system in one single step without a need to separately analyze each part of the domain. The cherry-picked earthquake excitations, viz, the 1999 Chi-Chi (Taiwan), and 2011 Kohriyama (Japan), were scaled by means of the widely-used response spectrum matching method as per the design response spectrum of a strong rock. The plastic moment concept was employed so as to assign the elastic-perfectly plastic model to the superstructure and its foundation. Additionally, the strain-compatible shear modulus and damping dependency on the cyclic shear strain were considered via the programmed hysteretic damping algorithm. The numerical predictions included the response spectra at the seismic bedrock and ground surface, base shear forces, shear force distributions along the building height, maximum and permanent foundation displacements, and foundation rocking, plus the flooring lateral deflections and inter-story drifts. The life safety limits for the transient and residual total in...

Yu, Y, Dackermann, U, Li, J & Niederleithinger, E 2019, 'Wavelet packet energy-based damage identification of wood utility poles using support vector machine multi-classifier and evidence theory', STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL, vol. 18, no. 1, pp. 123-142.
View/Download from: Publisher's site

Yu, Y, Li, J, Li, Y, Li, S, Li, H & Wang, W 2019, 'Comparative Investigation of Phenomenological Modeling for Hysteresis Responses of Magnetorheological Elastomer Devices', International journal of molecular sciences, vol. 20, no. 13.
View/Download from: Publisher's site
View description>>

Magnetorheological elastomer (MRE) is a type of magnetic soft material consisting of ferromagnetic particles embedded in a polymeric matrix. MRE-based devices have characteristics of adjustable stiffness and damping properties, and highly nonlinear and hysteretic force-displacement responses that are dependent on external excitations and applied magnetic fields. To effectively implement the devices in mitigating the hazard vibrations of structures, numerically traceable and computationally efficient models should be firstly developed to accurately present the unique behaviors of MREs, including the typical Payne effect and strain stiffening of rubbers etc. In this study, the up-to-date phenomenological models for describing hysteresis response of MRE devices are experimentally investigated. A prototype of MRE isolator is dynamically tested using a shaking table in the laboratory, and the tests are conducted based on displacement control using harmonic inputs with various loading frequencies, amplitudes and applied current levels. Then, the test results are used to identify the parameters of different phenomenological models for model performance evaluation. The procedure of model identification can be considered as solving a global minimization optimization problem, in which the fitness function is the root mean square error between the experimental data and the model prediction. The genetic algorithm (GA) is employed to solve the optimization problem for optimal model parameters due to its advantages of easy coding and fast convergence. Finally, several evaluation indices are adopted to compare the performances of different models, and the result shows that the improved LuGre friction model outperforms other models and has optimal accuracy in predicting the hysteresis response of the MRE device.

Yu, Y, Subhani, M, Dackermann, U & Li, J 2019, 'Novel Hybrid Method Based on Advanced Signal Processing and Soft Computing Techniques for Condition Assessment of Timber Utility Poles', Journal of Aerospace Engineering, vol. 32, no. 4.
View/Download from: Publisher's site
View description>>

© 2019 American Society of Civil Engineers. Recently, a variety of nondestructive evaluation (NDE) approaches have been developed for health assessment and residual capacity estimation of timber structures. Among these methods, guided wave (GW)-based techniques are highly regarded as effective tools for potential use in real situations. Nevertheless, because it is hard to comprehensively grasp the behavior of wave propagation in a wood structure, existing NDE-based techniques mainly depend on an oversimplified hypothesis, which can result in inaccurate or even misleading results in practice. Understanding the complex behavior of GW propagation in wood structures and extracting appropriate information from captured GW signals is a key for successful assessments of in situ conditions of timber structures. This paper analyzes the existing feature extraction and damage detection algorithms, and proposes a novel approach based on an integration of wavelet packet transform (WPT) and ensemble empirical mode decomposition (EEMD) for extracting damage-sensitive patterns, and then a soft computing method like support vector machine (SVM) for pole condition identification. In the proposed method, GW signals measured from a multisensing system with pole health condition as the baseline are divided into a series of subfrequency bands based on WPT. Then EEMD is adopted to extract the intrinsic mode functions (IMFs) that possess the features extracted at corresponding subfrequency bands. Hence, the IMF component was segregated from the original signals of tested poles, and the IMF Shannon entropy was employed to build up the feature vector to effectively demonstrate the health condition. To decrease the size of the feature vector and avoid multiple collinearity among obtained patterns, principal component analysis was employed and entropy information in the feature vector was replaced with main principal components, which will be employed as input variables of the developed SVM...

Yu, Y, Wang, C, Gu, X & Li, J 2019, 'A novel deep learning-based method for damage identification of smart building structures', STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL, vol. 18, no. 1, pp. 143-163.
View/Download from: UTS OPUS or Publisher's site

Zhang, G, Li, Y, Wang, H & Wang, J 2019, 'Rheological properties of polyurethane-based magnetorheological gels', Frontiers in Materials, vol. 6.
View/Download from: Publisher's site
View description>>

© 2019 Zhang, Li, Wang and Wang. The paper tests the influence of mass fractions of carbonyl iron particles (CIPs) on the rheological properties of magnetorheological (MR) gels. Polyurethane-based MR gels with different weight fraction of CIPs, i.e., 40, 60, and 80%, were firstly prepared by mechanical mixing, respectively. The changes of shear stress and viscosity with shear rate under different magnetic flux density were tested and analyzed. It was found that the shear stress increases with mass fraction under magnetic flux density. The viscoelastic properties of MRGs were achieved by oscillatory shear measure. The effects of strain amplitude and frequency on viscoelastic of MRGs under different magnetic flux density were measured and analyzed. The study results shown that the elastic characteristics become more obvious with the increase of CIPs mass fraction. However, it has opposite effect on the viscous properties of materials.

Zhao, L-S, Zhou, W-H, Geng, X, Yuen, K-V & Fatahi, B 2019, 'A closed-form solution for column-supported embankments with geosynthetic reinforcement', GEOTEXTILES AND GEOMEMBRANES, vol. 47, no. 3, pp. 389-401.
View/Download from: UTS OPUS or Publisher's site

Aghayarzadeh, M, Khabbaz, H & Fatahi, B 2018, 'Evaluation of Concrete Bored Piles Behaviour in Saturated Loose and Dense Sand During the Static Load Testing', New Developments in Materials for Infrastructure Sustainability and the Contemporary Issues in Geo-environmental Engineering, GeoChina International Conference, Springer, Hangzhou, China, pp. 75-89.
View/Download from: UTS OPUS or Publisher's site
View description>>

Diversity of construction methods is available for the installation of piles; and generally piles are classified into two main groups in terms of their installation method, including non-displacement piles and displacement piles. However, non-displacement piles such as bored piles or drilled shafts cause less disruption to adjacent soil compared to displacement piles. Knowing the behaviour of piles, the load-displacement curve has an important role during the pile load testing. In this study, firstly, the background and concepts of three different constitutive soil models including Mohr-Coulomb, Hardening Soil and Hypoplastic models are discussed. Secondly, using these soil models and finite element software PLAXIS, the load carrying capacity of a single bored pile in saturated dense and loose sand are evaluated. Finally, different factors affecting load-displacement curve including Hypoplastic model parameters are assessed. The most important aim of this study is comparing the capability of different soil models to capture the large strain behaviour observed during the static load testing. The results revealed that all three soil models indicate a reasonable correlation to each other, except when the “Intergranular Strain” concept, defined in Hypoplastic model, is activated. This paper can be useful for the practicing engineers to identify the effect of different soil models in numerical simulation of static pile load testing.

Aghayarzadeh, M, Khabbaz, H & Fatahi, B 1970, 'Evaluation of Reaction Piles Effect on Test Piles in Static Load Testing Using 3-D Numerical Analysis', International Conference on Stress Wave Theory and Testing Methods for Deep Foundations, San Diego, California, USA.
View/Download from: UTS OPUS
View description>>

Static load testing includes the direct measurement of pile head displacements when a physical test load is applied. It is known as the most fundamental form of pile load testing, and generally considered as a benchmark for pile performance assessment. During static load testing, the load is commonly applied using a hydraulic jack acting against a reaction beam, which is restrained by an anchorage system. The anchorage system may be in the form of cable anchors or reaction piles installed into the ground to provide tension resistance. In this paper, PLAXIS 3D software incorporating elastic-perfectly-plastic Mohr-Coulomb and hardening-soil constitutive models is initially used to simulate a real static load test conducted in stiff overconsolidated clay. Then, in order to assess the effect of the reaction system on the test results, a similar model using the hardening soil model is simulated. In the three-dimensional model, different numbers of reaction piles, identical to the test pile are located in different distances from the test pile. Subsequently, the influences of spacing, length, diameter of reaction piles, and type of reaction piles on the load - displacement behavior of test piles are assessed. This paper can provide insight to practicing civil engineers on how to design the loading systems for static pile load tests.

Dang, LC & Khabbaz, M 2019, 'Shear Strength Behaviour of Bagasse Fibre Reinforced Expansive Soil', International Conference on Geotechnical and Earthquake Engineering 2018.
View/Download from: UTS OPUS or Publisher's site
View description>>

This paper presents an experimental investigation on the shear strength behaviour of expansive soil reinforced with bagasse fibre. Bagasse fibre, an agricultural waste by-product left after crushing of sugar-cane for juice extraction, was employed in this study as a reinforcing component for expansive soil reinforcement. The expansive soil used in this investigation was collected from Queensland, Australia. To experimentally investigate the influence of bagasse fibre reinforcement on the shear strength of expansive soil, a series of non-reinforced and fibre reinforced soil samples was prepared by changing randomly distributed bagasse fibre content from 0% to 2%. An array of intensive experimental tests using triaxial compression apparatus was carried out and its results are presented and discussed in further detail. The experimental results reveal that bagasse fibre reinforcement exhibited significant effects on shear strength characteristics of reinforced soils in terms of relationships between deviatoric stress and axial shear strain, ultimate deviatoric strength, and shear strength parameters.

Dang, LC & Khabbaz, MH 2018, 'Experimental Investigation on the Compaction and Compressible Properties of Expansive Soil Reinforced with Bagasse Fibre and Lime', Recent Advancements on Expansive Soils: Proceedings of the 2nd GeoMEast International Congress and Exhibition on Sustainable Civil Infrastructures, Egypt 2018 – The Official International Congress of the Soil-Structure Interaction Group in Egypt (SSIGE), GeoMEast International Congress and Exhibition on Sustainable Civil Infrastructures, Egypt 2018 – The Official International Congress of the Soil-Structure Interaction Group in Egypt (SSIGE), Springer, Egypt.
View/Download from: Publisher's site
View description>>

This paper presents a laboratory investigation into the mechanical characteristics of expansive soil reinforced with randomly distributed bagasse fibre and lime combination. Bagasse fibre, an agricultural waste by-product left after crushing of sugar-cane for juice extraction, was employed in this investigation as a reinforcing component for expansive soil reinforcement. Several series of laboratory experiments including standard compaction and consolidation tests were carried out on untreated soil and soil samples mixed with various contents of bagasse fibre in a wide range from 0% to 2% and a certain amount of 2.5% lime. The experimental results were used to comprehend the effects of adding bagasse fibre on the compaction and compressible properties of fibre reinforced soils with lime stabilisation. The compaction test results indicate that the addition of bagasse fibre, hydrated lime, and their combination decreased the dry density of stabilised soils. Moreover, the obtained results of the consolidation tests reveal that the reinforcement of expansive soil with bagasse fibre improved the pre-consolidation pressure, meanwhile tended to reduce the compression characteristics of the lime stabilised soils as bagasse fibre content increased from 0% to 1%. However, an excessive increase in bagasse fibre content beyond 1% to 2% was found to result in a slight reduction of the compressibility of lime-soil mixtures reinforced with bagasse fibre. The findings of this research provide a deeper insight into promoting applications of an agricultural waste by-product of bagasse fibre as a low-cost and eco-friendly material for treatment of expansive soils and fill materials for sustainable construction development in the field of civil infrastructure foundations.

Dong, Y, Fatahi, B, Khabbaz, H & Hsi, J 2018, 'Impact of Initial In-Situ Stress Field on Soil Response During Cavity Expansion Using Discrete Element Simulation', New Developments in Materials for Infrastructure Sustainability and the Contemporary Issues in Geo-environmental Engineering, GeoChina International Conference, Springer, Hang Zhou, China, pp. 1-10.
View/Download from: UTS OPUS or Publisher's site
View description>>

Discrete element method (DEM) is gaining its popularity in investigating many complicated geotechnical related problems due to its discontinuous nature in simulating granular materials. Particularly when simulating the processes involving large deformation and displacement of soil (e.g. pile penetration), DEM demonstrates distinct advantages over other numerical solutions that may confront convergence problems. Despite the facts that DEM analysis has been conducted to study the mechanism of the cavity expansion, there is a very limited number of investigations conducted to study the effects of the initial stress field on the soil response. Hence, in this study, a three-dimensional numerical analysis has been conducted using PFC3D to investigate the soil response under different initial stress conditions during cavity expansion. A large-scale model containing an adequate number of particles has been constructed to simulate the soil medium, in which, microscopic contact properties were calibrated against existing experimental data to mimic the realistic behaviour of a sandy soil. To examine the effects of the initial in-situ stresses, several cylindrical cavities were created and expanded gradually from an initial radius to a final radius, while stress and strain variations were monitored during the entire simulation. It should be noted that the internal cylinder boundary was loaded using a constant strain rate, while the outer boundary was controlled through a servo mechanism to maintain a constant external pressure adopting appropriate subroutines. The results obtained confirmed that the initial stress conditions have significant effects on the soil response during cavity expansion.

Gowripalan, N, Cao, J, Sirivivatnanon, V & South, W 2019, 'Assessment of ASR expansions using an ultra-accelerated test', 29th Biennial Conference of the Concrete Institute of Australia, Sydney Australia.
View/Download from: UTS OPUS

Hoang, VT, Phung, MD, Dinh, TH & Ha, Q 2018, 'Angle-Encoded Swarm Optimization for UAV Formation Path Planning', 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), International Conference on Intelligent Robots and Systems, IEEE, Madrid, Spain.
View/Download from: UTS OPUS or Publisher's site
View description>>

This paper presents a novel and feasible path planning technique for a group of unmanned aerial vehicles (DAVs) conducting surface inspection of infrastructure. The ultimate goal is to minimise the travel distance of DAVs while simultaneously avoid obstacles, and maintain altitude constraints as well as the shape of the UAV formation. A multiple-objective optimisation algorithm, called the Angle-encoded Particle Swarm Optimization (θ- PSO) algorithm, is proposed to accelerate the swarm convergence with angular velocity and position being used for the location of particles. The whole formation is modelled as a virtual rigid body and controlled to maintain a desired geometric shape among the paths created while the centroid of the group follows a pre-determined trajectory. Based on the testbed of 3DR Solo drones equipped with a proprietary Mission Planner, and the Internet-of- Things (loT) for multi-directional transmission and reception of data between the DAV s, extensive experiments have been conducted for triangular formation maintenance along a monorail bridge. The results obtained confirm the feasibility and effectiveness of the proposed approach.

Le, TM, Dang, LC & Khabbaz, H 2019, 'Combined Effects of Bottom Ash and Lime on Behaviour of Expansive Soil', Recent Advancements on Expansive Soils, Springer International Publishing, pp. 28-44.
View/Download from: UTS OPUS
View description>>

This study illustrates the effectiveness of combining bottom ash and hydrated lime to enhance the engineering properties of expansive soil. The bottom ash was collected from Eraring Power Station in New South Wales, Australia, as a by-product of coal-fired power stations, and soil specimens were used as artificial soil including kaolinite, bentonite and fine sand in a reasonable ratio to stimulate soil samples with characteristics of expansive soil. The stabilised soil samples were prepared by altering the bottom ash content from 0% to 30% on a dry weight basis of expansive soil as well as with constant percentage of 5% in hydrated lime. Through conducting a series of experimental tests including linear shrinkage and unconfined compressive strength (UCS) in various curing time, the shrinkage and strength behaviour of treated soils were investigated and compared with untreated soil samples. The results revealed that the combination of bottom ash and hydrated lime significantly reduced the linear shrinkage, while it increased the strength of expansive soil. The use of bottom ash alone is not recommended due to a slight increase of linear shrinkage and a minor negative impact on the soil strength. The optimum content of combined bottom ash and hydrated lime to stabilise expansive soils is also presented.

Le, TM, Dang, LC & Khabbaz, H 2019, 'Strength characteristics of lime and bottom ash reinforced expansive soils', Geotechnical Special Publication, pp. 352-362.
View/Download from: UTS OPUS or Publisher's site
View description>>

© 2019 American Society of Civil Engineers. The primary aim of study is to evaluate the influence of hydrated lime and bottom ash on strength properties of expansive soil by two different kinds of dry-weight-based ratios. In this research, bottom ash is used as a stabilizing agent for expansive soil stabilization due to the potential benefits of its additional pozzolanic components in combination of hydrated lime. Bottom ash is a by-product of coal-fired process which was collected from Eraring Power Station in New South Wales, Australia. Meanwhile, expansive soils were artificially prepared using a proper combination of kaolinite, bentonite, and Sydney fine sand to constitute soil samples typically representing expansive soil in the region. To determine the optimum combination ratio of bottom ash to lime to stabilize expansive soil, different contents of randomly distributed bottom ash from 5% to 30% were mixed with soil and 5% hydrated lime to investigate the engineering behaviour of stabilized expansive soils. It is noted that the additive contents of lime and bottom ash, adopted in this study, were calculated based on both the dry weight of soil alone and the total weight of bottom ash-lime-soil admixture for the comparison purpose. The results of indirect tensile (IDT) strength and California bearing ratio (CBR) tests after various curing times are presented and discussed. The experimental findings show that a ratio of 5% lime to 20% bottom ash mixed with expansive soil is considered as their optimum combination ratio for achieving the maximum bearing capacity and tensile strength for soil-dry-weight-based additives. However, the optimum combination ratio of 5% lime to 25% bottom ash is determined in the case of the entire mixture-dry-weight-based additives. It is concluded that applying the latter optimum ratio to a combination of lime and bottom ash can improve the expansive soil strength better than the former.

Li, J & Wu, C 2018, 'Experimental and numerical study on Basalt scale aluminium foam', 7th International Conference on Protection of Structures against Hazards, Hanoi.

Li, J & Wu, C 2018, 'Experimental study on ultra-high performance concrete columns against low-velocity impact', Proceedings of the 25th Australasian Conference on Mechanics of Structures and Materials, 25th Australasian Conference on the Mechanics of Structures and Materials, Brisbane.

Nguyen, TN, Yu, Y, Li, J, Gowripalan, N & Sirivivatnanon, V 2019, 'Mechanical properties of ASR affected concrete: a critical review', Concrete 2019, Sydney.
View/Download from: UTS OPUS

Roboredo, C, Thomas, P, Vessalas, K & Sirivivatnanon, V 2018, 'ALKALI LIMIT IN CEMENT WITH SUPPLEMENTARY CEMENTING MATERIALS – A REVIEW', The International Federation for Structural Concrete 5th International fib Congress, The International Federation for Structural Concrete Congress, Melbourne.
View/Download from: UTS OPUS
View description>>

The alkali silica reaction (ASR) may cause deleterious cracking in concretes as a result of the reactions of reactive aggregates in concrete systems that contain elevated alkali contents. Current strategies applied in the mitigation of ASR are based on limiting the alkali content (Na2Oe) of the cement and concrete and through the screening of aggregates with additional surety provided by the use of supplementary cementitious materials (SCMs) in the partial replacement of cement. These strategies pose significant issues for the construction materials industry through increased manufacturing costs and reduction in volumes of viable raw materials that meet the imposed criteria. The effective mitigation of deleterious ASR using SCMs should change the focus of regulators and standards authorities to risk management through the assessment of the risk profile of a concrete mix in a particular application. Using a risk profile to assess alkali limits has the potential to relax alkali limits in cements. To achieve this aim a deep understanding of ASR in cement-SCM-aggregate concrete mixes is required through laboratory testing correlated with long-term field performance. This paper reviews ASR, reactivity assessment of aggregates and the role of SCMs in ASR mitigation and proposes a change in the focus to a balanced alkali limit based on assessed risk for the occurrence of deleterious ASR.

Sarikaya, A, Erkmen, RE, Gowripalan, N, Sirivivatnanon, V & South, W 2019, 'A Plastic-Damage Model for Concrete under Cyclic Loads', Concrete 2019, Sydney, Australia.
View/Download from: UTS OPUS
View description>>

A constitutive model based on a novel coupled elastoplastic-damage framework is adopted for the modelling of concrete under cyclic loads. Coupled elastoplastic-damage models have been used to capture both the material degradation and the permanent deformations under inelastic deformations. In this study, a multisurface plasticity framework is implemented for the modelling of concrete under compressive and tensile cyclic loads. The elastoplastic-damage framework is based on the ‘direct-coupling’ method in which an a-priori relationship between the total strain and the damage strain is postulated. The model is easy to calibrate since it utilises the same yield and potential functions for plasticity and damage calculations. Concrete is modelled using a pair of yield surfaces in order to capture its compressive and tensile behaviour while utilising corresponding isotropic damage variables to capture the stiffness degradations in the compressive and tensile regimes. Material parameters are calibrated using uniaxially loaded concrete experiments. The results are compared with experimental and numerical data provided in the literature.

Tapas, M, Vessalas, K, Thomas, P & Sirivivatnanon, V 2019, 'An AMBT Study on the Effect of Limestone on ASR Mitigation: Ground Limestone Vs. Interground Limestone in Cements', Proceedings of the International Conference on Sustainable Materials, Systems and Structures (SMSS2019) Durability, Monitoring and Repair of Structures, International Conference on Sustainable Materials, Systems and Structures, RILEM Publications S.A.R.L., Rovinj, Croatia, pp. 201-207.
View/Download from: UTS OPUS

Tapas, M, Vessalas, K, Thomas, P, Sirivivatnanon, V & Kidd, P 2019, 'Mechanistic Role of Supplementary Cementitious Materials (SCMs) in Alkali-Silica Reaction (ASR) Mitigation', Concrete in Practice-Progress Through Knowledge, Sydney, Australia.
View/Download from: UTS OPUS

Vu, TH, Gowripalan, N, Sirivivatnanon, V, De Silva, P & Kidd, P 2019, 'Assessing Corrosion Resistance of Powder form of Geopolymer Concrete', 29 Biennial Conference of the Concrete Institute of Australia, Sydney Australia.
View/Download from: UTS OPUS

Yu, Y, Nguyen, TN, Li, J & Sirivivatnanon, V 2019, 'Soft computing techniques for evaluation of elastic modulus of ASR affected concrete', Concrete 2019, Sydney.
View/Download from: UTS OPUS

Yu, Y, Nguyen, TN, Li, J & Sirivivatnanon, V 2019, 'Soft computing techniques for evaluation of elastic modulus of ASR affected concrete', Concrete 2019: Concrete in Practice – Progress Through Knowledge, Sydney.
View/Download from: UTS OPUS

Zhang, X, Fatahi, B & Khabbaz, H 2018, 'Investigating Effects of Individual Fracture Length on Behaviour of Weak Rock Using Discrete Element Method', Proceedings of the 5th GeoChina International Conference 2018 – Civil Infrastructures Confronting Severe Weathers and Climate Changes: From Failure to Sustainability, 5th GeoChina International Conference, Wuhan, pp. 1-11.
View/Download from: UTS OPUS