型钢混凝土压弯构件受力性能数值模拟及影响参数分析

Numerical simulation and influence paramter analysis for the performance of SRC compression-bending members

准确地预测地震荷载作用下型钢混凝土压弯构件的受力性能,对评估带有该类构件的超高层建筑结构的震害程度和分析其地震安全性具有重要意义。因型钢混凝土压弯构件复杂的材料特性和受力行为,在反复荷载作用下其受力性能的数值模拟尚存欠缺。本文采用开源有限元结构分析软件Open Sees,基于柔度法纤维模型,将型钢混凝土压弯构件中的混凝土按受约束情况,划分为3部分:箍筋以外的无约束混凝土,受型钢翼缘约束的强约束混凝土,位于上述两者之间的弱约束混凝土,并确定了相应的钢和混凝土材料本构模型,给出了型钢混凝土压弯构件数值模拟方法。采用该方法对低周反复荷载作用下9个不同轴压比的型钢混凝土压弯试验构件进行了全过程有限元数值模拟。得到的数值模拟结果与试验结果吻合较好,表明本文所建立的型钢混凝土压弯构件的数值模拟模型和方法是合理、可行的,达到了精度和效率的统一,可进一步推广应用到带有该类构件的大型复杂超高层建筑结构的动力非线性分析中。采用本文模型和方法还分析了轴压比、混凝土强度等级、型钢强度等级和含钢率等对构件骨架曲线的影响,结果表明这些参数均对型钢混凝土构件的刚度、强度和延性有不同程度的影响。

Accurately predicting the bearing behavior of steel reinforced concrete （SRC） compression-bending members under seismic loads has important meaning to assess the degree of earthquake damage and analysis the seismic safety of super high-rise building structures with this kind of members. Due to the complicated material fea- ture and force behavior of steel reinforced concrete members, there is some lack of the bearing behavior numericalsimulation of SRC under cyclic loading. In this paper, using the finite element analysis software OpenSees, a nu- merical simulation method is developed based on the force-based fiber model. In this model, the concrete in the kind of member is divided into three parts： unconfined concrete, partially confined concrete and highly confined concrete. The hysteretic model of steel and concrete is defined. Nine SRC compression-bending members with dif- ferent axial load ratios, which are tested under low cyclic loading, are analyzed by this method. The numerical sim- ulation results agree well with the test results. It is shown that the numerical simulation model and method of steel reinforced concrete is reasonable and feasible, and achieve unity of the accuracy and efficiency. This method can be extended to use in nonlinear dynamic response analysis of super high-rise building structures with this kind of members. The influences of axial compression ratio, concrete strength grade, steel strength grade and steel ratio on the skeleton curves are also analyzed, which indicate that these parameters have different effects on the stiffness, strength and ductility of steel reinforced concrete members.