摘要：基于统一强度理论，推导了钢管混凝土柱的塑性极限弯矩和均布荷载作用下简支梁的极限位移。考虑爆炸反应过程中钢管混凝土柱质量和刚度改变产生的非线性影响，采用等效单自由度模型和逐步积分法，分析了爆炸荷载作用下钢管混凝土柱的动态响应。将理论计算结果与相关文献计算结果进行对比，验证了理论计算方法的正确性。研究结果表明：随着套箍系数的增大，塑性极限弯矩及极限位移增大；随着侧压系数的增大，塑性极限弯矩增大；考虑钢管对受压区混凝土抗压强度的提高比不考虑时塑性极限弯矩提高了12%～19%；提出的计算方法满足钢管混凝土柱抗爆分析的精度要求，可为钢管混凝土柱的抗爆设计和防护提供参考。
关键词：爆炸荷载；钢管混凝土柱；统一强度理论；塑性极限弯矩；等效单自由度模型；逐步积分法
中图分类号：TU398.1文献标志码：A
Abstract： The plastic ultimate moment of concretefilled steel tubular and the ultimate displacement of the simply supported beam under uniformly distributed load were derived based on unified strength theory. Considering nonlinear impact of mass and stiffness changed in the process of the reaction， the dynamic responses of concretefilled steel tubular columns under blast load were analyzed by the equivalent single degree of freedom model and step by step integration method. The results of this method were compared with relevant literatures and the accuracy of the method was verified. The study results show that the plastic ultimate moment and the ultimate displacement increase along with the increase of hoop coefficient； the plastic ultimate moment also increases along with the increase of lateral pressure coefficient； the plastic ultimate moment considering the improvement of the compressive strength of concrete increases 12%19% than that without considering the improvement. The proposed method is satisfied for the requirement of the analytical precision， and can be referred for the research and the safety of concretefilled steel tubular columns under blast load.
Key words： blast load； concretefilled steel tubular column； unified strength theory； plastic ultimate moment； equivalent single degree of freedom model； step by step integration method
0引言
本文基于统一强度理论，推导圆钢管混凝土柱的塑性极限弯矩和均布荷载作用下简支梁的极限位移。考虑爆炸反应过程中钢管混凝土柱质量和刚度改变产生的非线性影响，采用等效单自由度模型和逐步积分法，迭代求解爆炸荷载作用下钢管混凝土柱的最大位移。比较最大位移与极限位移的关系，判断钢管混凝土柱是否发生破坏，为爆炸荷载作用下钢管混凝土柱的抗爆研究提供参考。
1均布荷载下的塑性极限弯矩及破坏位移对于均布荷载作用下的圆钢管混凝土柱，假定[6]：①截面应变保持平面；②受压区由钢管和混凝土共同承受；③纤维屈服时，忽略拉区混凝土的抗拉强度；④不考虑材料的应变率效应。
5结语
（1）本文采用统一强度理论求解钢管混凝土柱的塑性极限弯矩，考虑了钢管对受压区混凝土抗压强度的提高作用；采用逐步积分法求解钢管混凝土柱的动态响应，考虑了反应过程中钢管混凝土柱质量和刚度改变产生的非线性影响。结果表明，本文方法具有较好的计算精度，且适用于任何材料特性的非线性形式。
（2）随着钢管对混凝土约束作用的提高，塑性极限弯矩随之增大，极限位移也随之增大；考虑钢管对受压区混凝土抗压强度的提高比不考虑时塑性极限弯矩提高了12%～19%。 （3）采用本文方法，可以判定在固定爆炸荷载作用下钢管混凝土柱是否发生破坏。参考文献：
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