【摘要】 基于材料本构关系的纤维模型能有效模拟柱在变轴力与双向弯矩耦合作用下的非线性反应,但常规的纤维模型分析方法忽略了纵筋滑移。在纤维模型基础上,采取在非线性梁柱单元端部附加零长度截面单元的方法以模拟杆端纵筋滑移的影响。以钢筋混凝土柱为例,将弯曲转角、滑移引起的固端转角等模拟结果分别与柱在低周反复荷载作用下的试验数据进行对比,校准了该模型化方法。考察了6层钢筋混凝土平面框架的非线性地震反应,研究了底层柱根纵筋滑移对框架整体和局部反应的影响。结果表明,模拟分析的纵筋滑移规律与柱的试验结果相符较好。底层柱根纵筋滑移有增大框架整体非线性地震反应的趋势,并将改变底层柱非线性变形的组成方式,减小其柱端塑性铰区的非线性弯曲变形。更多还原

【Abstract】 Fiber model that is based on the constitutive models of the materials can simulate the nonlinear responses of columns under biaxial bending and varying axial force effectively,but bar slippage is always neglected in the conventional fiber model analysis.Based on the fiber model,a zero-length section element was combined at the end of the nonlinear beam-column element,which was used to simulate the bar slippage at ends of the member.The simulated flexural rotation and fixed end rotation due to bar slippage of a reinforced concrete column were compared with the corresponding experimental results,respectively,and the ability of the proposed model to capture bond-slip effects was calibrated.By investigating the nonlinear seismic responses of a six storey RC planar frame,the effects of the bar slippage at column bottom section to the global and local responses of the frame were analyzed.The results show that experimental bar slippage at the column end is in a good agreement with the simulated results.The bar slippage at column bottom end at the first floor tends to increase global seismic response of the frame,change components of the nonlinear deformation at first floor column,and decrease nonlinear flexure deformation of the plastic hinge zone at column bottom ends.更多还原