高温后圆钢管再生混凝土轴压短柱的极限承载力研究

为了研究火灾高温后圆钢管再生混凝土轴压短柱的受力性能及极限承载力,以再生粗骨料取代率、恒温温度和恒温时间为变化参数,对20个设计的圆钢管再生混凝土短柱试件进行火灾高温后的力学性能试验。并对各变化参数对圆钢管再生混凝土短柱极限承载力的影响进行分析。利用统一强度理论和叠加计算理论分别计算高温后其极限承载力,并与试验实测结果比较。研究结果表明:高温后钢管再生混凝土短柱的受力破坏过程和形态与普通钢管混凝土柱相似;火灾温度对承载力影响显著;同一温度下,承载力随恒温时间的延长呈先上升后下降的趋势;骨料取代率对试件的承载力影响不大;采用统一强度理论中钟善桐计算法对高温后圆钢管再生混凝土短柱的极限承载力进行计算,计算值与试验值吻合较好。

STUDY OF ULTIMATE BEARING CAPACITY OF RECYCLED AGGREGATE CONCRETE-FILLED CIRCLE STEEL TUBE SHORT COLUMNS UNDER AXIAL COMPRESSION AFTER HIGH TEMPERATURE

To study the mechanical behavior and ultimate bearing capacity of recycled aggregate concrete-filled circle steel tube short columns under axial compression after high temperature,20 recycled aggregate concrete-filled circular steel tubular short columns specimens were designed and tested,and three varying parameters were considered in the test,which were recycled coarse aggregate replacement percentage, constant temperature and constant temperature time. The influences of different parameters on ultimate bearing capacity of specimens were analyzed. Unified strengthen theory and superposition calculation theory were used to calculate the ultimate bearing capacity of specimens,whose results were compared with the test results. The results of study showed that the failure process and form of recycled aggregate concretefilled circular steel tubular columns under axial compression after high temperature were similar to ordinary concrete-filled steel tube columns. Constant temperature had significant effect on the bearing behavior. Bearing capacity with the extension of constant temperature time showed a trend of first increase and then decrease at the same temperature;aggregate replacement had little effect on bearing capacity; the unified strengthen theory calculation formulas proposed by Zhong Shantong was used to calculate ultimate bearing capacity of recycled aggregate concrete-filled circular steel tubular short columns after high temperature,the calculated results agreed well with the test results.