Experimental researches on behavior of high-performance concrete filled tubular steel stub columns after high temperature

摘要

Based on experimental studies of 36 high-performance concrete filled tubular steel stub columns after high temperature and 6 high-performance concrete filled tubular steel stub columns under ordinary temperature which concrete strength grade is C80, the principal factors of peak temperature, peak temperature maintenance time and steel ratio on ultimate loading capacity for high- performance concrete filled tubular steel stub columns after high temperature are discussed. Experiments show: With the exposure temperature up and maintenance time increase, ultimate loading capacity for high-performance concrete filled tubular steel stub columns after high temperature tend to decrease as a whole. However, ultimate loading capacity for high-performance concrete filled tubular steel specimens after high temperature just fluctuates slightly under 500°C, but decreases sharply above 500°C. With steel ratio increasing, ultimate loading capacity for high-performance concrete filled tubular steel stub columns after high temperature increases slightly. Furthermore, the calculation formula for ultimate loading capacity for HPCFTS after high temperature also is presented. And the calculation formula also can be applied in normal strength concrete filled tubular steel stub columns and high- strength concrete filled tubular steel stub columns. A comparison of calculated results with experimental results shows good agreement.