Test on Axial Compression Performance and Residual Bearing Capacity Assessment of Recycled Concrete Filled Circular Steel Tube After Exposure to High Temperatures and Water Cooling
CHEN Zongping1,2, ZHOU Ji1, WANG Cheng1, SU Weiwei1
1 College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China 2 Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education, Guangxi University, Nanning 530004, China
Abstract: In order to study the axial compression performance and residual bearing capacity evaluation method of recycled concrete filled circular steel tube (RCFCST) after elevated to high temperatures and water cooling, 27 RCFCST short columns were designed for axial compression test, with the variable parameters of recycled coarse aggregate replacement percentage, temperature and cooling method considered. By the experiment, the whole mechanical process and failure mode of all specimens were observed, and stress-strain curves of specimens were obtained, and the influence of different variation parameters on peak stress, peak strain and axial displacement ductility and energy dissipation were analyzed. The performance degradation process was analyzed by combining the rigidity degradation curves of the specimen. And referring to each regulation, the residual bearing capacity of the specimen after exposure to high temperatures and water coolingwas calculated. The results indicate that with the increase of the maximum temperature, the peak stress of the specimen subjected to high temperatures and water cooling decreases significantly, but the peak strain increases gradually, and the ductility and energy dissipation are the trend of increasing first and then decreasing. With the increase of the replacement percentage of recycled aggregate, the peak stress and strain of the specimen change little, the axial displacement ductility decreases first and then increases, and the energy dissipation decreases gradually. When the temperature is higher, the peak stress, strain, ductility and energy dissipation of specimens subjected to water cooling are larger than those of natural cooling specimens. In addition, the rigidity degradation rate of water cooling specimens will slow down with the increase of the highest temperature, while the rigidity degradation rate of specimens with different replacement percentage is close, and the rigidity degradation rate of water cooling specimens is faster than that of natural cooling specimens. After theoretical analysis, it is suggested to adopt the calculation method of AIJ code of Japan, and introduce the coefficient reduction of steel tube and concrete after high temperature to evaluate the residual bearing capacity of RCFCST short columns after water cooling at high temperature.
陈宗平, 周济, 王成, 苏炜炜. 高温喷水冷却后圆钢管再生混凝土短柱轴压性能试验及剩余承载力评估[J]. 材料导报, 2021, 35(7): 7033-7041.
CHEN Zongping, ZHOU Ji, WANG Cheng, SU Weiwei. Test on Axial Compression Performance and Residual Bearing Capacity Assessment of Recycled Concrete Filled Circular Steel Tube After Exposure to High Temperatures and Water Cooling. Materials Reports, 2021, 35(7): 7033-7041.
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