钢筋混凝土平面框架结构拟动力有限元分析

Finite Element Analysis for Pseudo-dynamic Behavior of Reinforced Concrete Plane Frame Structures

采用ABAQUS软件建立2层1榀1跨钢筋混凝土平面框架结构的三维实体精细有限元模型进行拟动力分析,模型考虑混凝土的塑性损伤和钢材的弹塑性混合强化性质、结构阻尼和连续地震引起的塑性损伤累积效应。在位移、恢复力的计算结果与已有拟动力试验结果符合较好的基础上,进一步分析该平面框架的结构损伤、塑性耗能分配机制以及混凝土、钢筋的应力-应变。结果表明:小震、中震作用下,平面框架结构基本处于弹性阶段,大震作用时进入塑性阶段;地震往复作用使梁柱节点处混凝土比柱底更容易压碎,1层梁比2层梁更容易破坏;梁的塑性耗能占比远远大于柱,该框架为典型的“强柱弱梁”结构体系;采用的建模分析方法能有效反映结构的损伤过程,可方便地用于实际工程的抗震性能评估。

Software ABAQUS was used to establish a three-dimensional solid finite element model of a 2-story 1-span reinforced concrete plane frame structure for pseudo-dynamic analysis.The model takes into account the plastic damage of concrete,the elastic-plastic mixed hardening properties of steel,the structural damping,and the cumulative effect of plastic damage caused by continuous earthquakes.The calculated results of displacement and restoring force are in good agreement with existing pseudo-dynamic test results,then the structural damage,the plastic energy dissipation distribution mechanism,and the stress-strain relationship of concrete and steel bar are further analyzed.The results showed that the plane frame structure is basically in the elastic stage under small and medium earthquakes,and enters the plastic stage under large earthquake.The concrete at the beam-column joints is easier to be crushed than that at the bottom of column,and the first floor beam is easier to be destroyed than the second floor beam.The plastic energy consumption of beam is much larger than that of column,indicating that the frame is a typical"strong column and weak beam"structural system.The modeling method adopted in this paper can effectively reflect the damage process of the structure,and can be conveniently used for seismic performance evaluation of practical projects.