- Fibre reinforced polymer (FRP) materials
- Ultra-high performance concrete (UHPC)
- Mechanics of Solids
- Structural mechanics
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: Publisher's site
Wang, W, Wu, C, Liu, Z & Si, H 2018, 'Compressive behavior of ultra-high performance fiber-reinforced concrete (UHPFRC) confined with FRP', Composite Structures, vol. 204, pp. 419-437.View/Download from: UTS OPUS or Publisher's site
© 2018 Elsevier Ltd This study presents the results of an experimental program on the compressive behavior of fiber reinforced polymer (FRP) confined ultra-high performance fiber-reinforced concrete (UHPFRC). A total of 38 specimens were prepared and tested under axial compression. In addition to FRP confined UHPFRC, FRP confined ultra-high performance concrete without fiber addition (UHPC), high strength concrete (HSC), and normal strength concrete (NSC) were also tested to investigate their comparative performances. The test results indicate that the FRP confined UHPFRC can exhibit ductile behavior if sufficient FRP confinement is provided. However, due to their ultra-high strength as well as the unique microstructure, FRP confined UHPFRC is likely to exhibit more brittle behavior than FRP confined NSC and HSC. Compared to FRP confined NSC and HSC, the confinement efficiency is less for FRP confined UHPFRC. Sudden stress reduction or stress fluctuations are observed shortly after the initial peak stress (axial stress at the first peak point) for FRP confined UHPFRC. Based on the confinement level, the stress-strain behavior of FRP confined UHPFRC may experience a second ascending branch or a continuous descending branch after the sudden stress reduction or stress fluctuations. The influences of FRP layers, FRP types, and fiber addition on the compressive behavior of FRP confined UHPFRC are observed to be significant. Moreover, existing stress-strain models available for FRP confined UHPFRC are evaluated by using a database collected in this study.
Wang, W, Wu, C & Li, J 2018, 'Numerical Simulation of Hybrid FRP-Concrete-Steel Double-Skin Tubular Columns under Close-Range Blast Loading', JOURNAL OF COMPOSITES FOR CONSTRUCTION, vol. 22, no. 5.View/Download from: UTS OPUS or Publisher's site
Wang, W, Sheikh, MN, Al-Baali, AQ & Hadi, MNS 2018, 'Compressive behaviour of partially FRP confined concrete: Experimental observations and assessment of the stress-strain models', Construction and Building Materials, vol. 192, pp. 785-797.View/Download from: UTS OPUS or Publisher's site
© 2018 Elsevier Ltd This study provides new insight on the compressive behaviour of partially fibre reinforced polymer (FRP) confined concrete with either strain-hardening or strain-softening responses. Fully FRP confined concrete, partially FRP confined concrete with different strip gaps, and unconfined concrete were tested under axial compression. Four types of axial load-axial deformation behaviours were observed for specimens with different strip gaps. Even though a high volumetric ratio of FRP was applied, the confinement effectiveness was negligible when the strip gap exceeded the diameter of the specimens. Moreover, the axial stress-axial strain behaviours of wrapped and non-wrapped concrete were observed to be different, and significant strain localization was observed within the non-wrapped region. Based on the experimental observations and an extensive literature review, a confinement effectiveness coefficient was proposed for partially FRP confined concrete. A stress-strain model was then developed by considering the proposed confinement effectiveness coefficient. The developed stress-strain model provided better predictions than other existing stress-strain models.
Wang, W, Martin, PR, Sheikh, MN & Hadi, MNS 2018, 'Eccentrically Loaded FRP Confined Concrete with Different Wrapping Schemes', Journal of Composites for Construction, vol. 22, no. 6.View/Download from: UTS OPUS or Publisher's site
© 2018 American Society of Civil Engineers. This study presents the results of an experimental program on the comparative performance of fiber-reinforced polymer (FRP) confined concrete specimens with different wrapping schemes. A total of 32 specimens in four groups were cast and tested under concentric and eccentric axial loads. All specimens were wrapped with the same amount of FRP but with different wrapping schemes, including full wrapping, partial wrapping, and nonuniform wrapping. Specimens in the first group were fully wrapped (Group F). Specimens in the second group were partially wrapped with 30 mm FRP strip spacing (Group P30). Specimens in the third group were partially wrapped with 60 mm FRP strip spacing (Group P60). Specimens in the fourth group were nonuniformly wrapped with a combination of full and partial wrapping (Group FP). Two similar specimens in each group were tested under concentric, 15 mm eccentric, 25 mm eccentric, and 40 mm eccentric axial loads. The test results indicate that fully wrapped specimens outperformed other groups of specimens under both concentric and eccentric axial loads, which were followed by nonuniformly and partially wrapped specimens. With the increase in axial load eccentricity, the performance in all groups significantly decreased. Moreover, with the increase in axial load eccentricity, the failure mode changed from FRP rupture at the compression side to extensive concrete cracking at the tension side. Equations were developed to predict the compressive strength of FRP confined concrete with different wrapping schemes. Experimental and analytical interaction (P-M) diagrams were also constructed to investigate the axial and flexural behavior of different groups of specimens.
Wang, W, Sheikh, MN, Hadi, MNS, Gao, D & Chen, G 2017, 'Behaviour of concrete-encased concrete-filled FRP tube (CCFT) columns under axial compression', Engineering Structures, vol. 147, pp. 256-268.View/Download from: UTS OPUS or Publisher's site
© 2017 Elsevier Ltd A new composite column named concrete-encased concrete-filled fibre reinforced polymer tube (CCFT) column has been proposed in this study. This composite column consists of an inner concrete-filled fibre reinforced polymer (FRP) tube, outer concrete confined with polymer grid, and concrete cover. In this study, a total of 16 concrete stub columns were cast and tested under axial compression. Columns were divided into eight groups, which included one group of plain concrete columns, two groups of FRP confined concrete columns, and five groups of CCFT columns. For FRP confined concrete columns, one layer and two layers of carbon FRP (CFRP) sheet were wrapped, respectively. For CCFT columns, glass FRP (GFRP) tube was used to confine the inner concrete, and polymer grid was used to confine the outer concrete. The test results show that considerable increase in strength and ductility can be obtained for CCFT columns. An analytical model has been developed to predict the axial compressive behaviour of CCFT columns. The analytical results have been found to be in good agreement with the experimental results. Based on the analytical model, the influences of different parameters on the axial compressive behaviour of CCFT columns have been investigated through parametric analyses.
Wang, W, Sheikh, MN & Hadi, MNS 2016, 'Experimental Study on FRP Tube Reinforced Concrete Columns under Different Loading Conditions', JOURNAL OF COMPOSITES FOR CONSTRUCTION, vol. 20, no. 5.View/Download from: Publisher's site
Gao, D, Chen, G, Hadi, MNS & Wang, W 2016, 'Mechanical properties and calculation method for ultimate tensile load of corroded steel fibres', Jianzhu Cailiao Xuebao/Journal of Building Materials, vol. 19, no. 3, pp. 436-441.View/Download from: UTS OPUS or Publisher's site
© 2016, Editorial Department of Journal of Building Materials. All right reserved. Steel fibres were corroded by using the method of drying-wetting cycles. Based on the investigation of their surface characters and according to the results of uniaxial tension test and finite element analysis, the effect of corrosion degrees on the deterioration of mechanical properties of corroded steel fibres was studied. Results show that many corrosion pits appear on the surface of the steel fibres after drying-wetting cycles. The deterioration of mechanical properties of corroded steel fibres is due to section loss and stress concentration at these pits. Moreover, the degrees of stress concentration depend on the varying pit depth, pit width and diameter of steel fibre. Finally, the deterioration model of ultimate tensile load of corroded steel fibres, considering the effects of pit depth, pit width and diameter of steel fibre, is proposed and verified by test results. Also, the model can be adopted for calculating the ultimate tensile load of corroded steel bars.
Wang, W, Sheikh, MN & Hadi, MNS 2016, 'Axial compressive behaviour of concrete confined with polymer grid', MATERIALS AND STRUCTURES, vol. 49, no. 9, pp. 3893-3908.View/Download from: Publisher's site
Gao, D, Chen, G, Sadraddin, HMN, Zhao, L, Wang, W & Li, C 2015, 'Bond-slip behavior and constitutive model between rebar and steel fibre reinforced concrete', Jianzhu Jiegou Xuebao/Journal of Building Structures, vol. 36, no. 7, pp. 132-139.View/Download from: Publisher's site
©, 2015, Science Press. All right reserved. The pull-out tests for bonding between rebar with inside strain gauges and steel fibre reinforced concrete (SFRC) were carried out to study the bond properties of specimens with varying concrete strengths. Based on the analysis of measured rebar strain, the distribution function of bond stress performed in cubic smooth spline was established. The distribution of bond stress and relative slip in bonded segment was obtained under the action of load at each stage, and the effects of steel fibre and concrete strength on bond properties were further analyzed. The results indicate that with the increasing of volume fraction of steel fibers and concrete strength, the bond stress of bonding specimens next to loaded end is improved and the ultimate bond stress moves to loaded end in general. Meanwhile, the slip at loaded end and free end were reduced. Finally, the bond-slip constitutive model reflecting the interaction process of rebar and SFRC was proposed.
Wang, W & Wu, C 2018, 'Numerical modelling of FRP-concrete-steel double-skin tubular columns under blast loading', Tubular Structures XVI - Proceedings of the 16th International Symposium on Tubular Structures, ISTS 2017, pp. 387-393.View/Download from: Publisher's site
© 2018 Taylor & Francis Group, London. This study presents a numerical study on the behavior of hybrid DSTCs under close-in blast loading. Numerical models of hybrid DSTCs were developed and validated. Afterwards, detailed numerical simulations were conducted to investigate the influences of different parameters on the behavior of hybrid DSTCs under blast loading. The mid-span deflection-time history were recorded and analyzed. The numerical simulation results indicate that the inner steel tube plays a key role in resisting the blast loading, while the contribution from outer FRP tube is less significant. Increasing the inner steel tube thickness and hollowness ratio can lead to a decrease of the maximum deflection of hybrid DSTCs. Under a lower axial load level, the maximum deflection will not increase with the increase of axial load. The influences of concrete strength and outer FRP tube thickness are insignificant.
Wang, W, Sheikh, MN, Hadi, MNS & Lyons, B 2014, 'Behaviour of GFRP tube reinforced concrete columns under axial compression', Proceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014, International Conference on FRP Composites in Civil Engineering (CICE), International Institute for FRP in Construction, Vancouver, Canada.View/Download from: UTS OPUS
This paper reports the result of an experimental investigation on the behaviour of Glass Fibre Reinforced Polymer (GFRP) tube reinforced concrete columns under axial compression. The GFRP tube was placed into the concrete to provide reinforcement both in the longitudinal and transverse directions. In this study, a total of 8 columns with 150 mm diameter and 300 mm height were cast and tested under axial compression. The columns were divided into four groups and each group contains two identical columns. The first group had two columns of plain concrete, and the remaining three groups were reinforced with solid, axially perforated and diagonally perforated GFRP tubes, respectively. The test results showed that for columns reinforced with solid GFRP tube, both the load-carrying capacity and the ductility capacity improved significantly. However, for axially perforated GFRP tube reinforced columns, the load-carrying capacity increased only slightly. For diagonally perforated GFRP tube reinforced columns, the ductility capacity improved notably, but the increase was less than the increase in the solid GFRP tube reinforced columns.