高温后钢管高性能混凝土轴压短柱力学性能研究

Researches on mechanical behavior of high-performance concrete filled tubular steel stub columns after high temperature

通过48根高温冷却后钢管高性能混凝土(C80)短柱的试验研究,探讨了火灾温度、恒温持续时间、含钢率等因素对高温后钢管高性能混凝土短柱极限强度、峰值应变、平台强度等的影响,并对构件高温后的工作机理进行了较深入的分析。试验表明,随着火灾温度的升高和恒温时间的增加,高温后钢管高性能混凝土短柱极限承载力整体上呈降低趋势,且温度高于500℃后,其下降速度更快,而在其他条件相同时,高温后钢管高性能混凝土短柱的极限承载力随含钢率增加略有提高。根据试验结果,建立了高温后钢管高性能混凝土组合材料应力 应变关系曲线计算公式和极限强度、峰值应变、平台强度、极限承载力等经验计算公式,其计算结果与实测结果吻合较好。

Based on experimental studies of 48 highperformance concrete filled tubular steel stub columns after high temperature, this paper discusses the principal factors of peak temperature, peak temperature maintenance time and steel ratio on the ultimate loading capacity of highperformance concrete filled tubular steel stub columns after high temperature. Experiment shows: with the exposure temperature up and the maintenance time increasing, the ultimate loading capacity of highperformance concrete filled tubular steel stub columns after high temperature tend to decrease as a whole. However, the ultimate loading capacity of highperformance concrete filled tubular steel specimens just fluctuates slightly under 500℃, but decreases sharply above 500℃. With steel ratio increasing, the ultimate loading capacity of highperformance concrete filled tubular steel stub columns increase slightly while the other conditions are same. This paper also presents the calculation formula for stressstrain curves of composite material of highperformance concrete filled tubular steel after high temperature and the empirical calculation formulas of ultimate strength,peak strain , remaining strength and ultimate loading capacity. A comparison of calculated results with experimental results shows good agreement.