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基于力插值纤维单元是目前钢筋混凝土结构非线性分析最常用的单元,它忽略单元的截面剪切变形,采用平截面假定,但对于剪力墙构件,其截面高度比较大,仍采用平截面假定忽略截面剪切变形将会造成较大的误差。基于这一背景,文中提出考虑截面剪切变形的修正基于力插值纤维单元(MFBFE),其截面不再是平截面,而是曲面,用以模拟剪力墙的地震反应非线性分析。基于OpenSees进行MFBFE单元开发,并对一组9个剪力墙试件进行水平低周往复模拟。实例分析结果显示较好地预测了构件的初始刚度、屈服力、极限力、卸载刚度、残余位移、延性和能量耗散,表明MFBFE单元模拟剪力墙地震反应非线性分析有较高的精度。并且对MFBFE单元在不同轴压比、不同高宽比、不同混凝土强度、不同纵向配筋率、不同约束区长度、不同配箍率下进行趋势分析。数据显示,文中提出的分析模型的适用范围很广,对于上述不同的计算和构造条件下都满足精度要求。
The force interpolation fiber unit is the most commonly used element in the nonlinear analysis of reinforced concrete structures at present. It neglects the section shear deformation of the unit and adopts the assumption of flat section. However, the cross-section height of the shear wall component is relatively large, Ignoring the cross-section shear deformation will cause greater error. Based on this background, the paper proposes a modification based on MFBFE to consider the shear deformation of the section. The section is no longer a flat section but a curved section to simulate the nonlinear analysis of the seismic response of the shear wall. The MFBFE unit was developed based on OpenSees, and a set of nine shear wall specimens were simulated for horizontal low-cycle reciprocation. The results of the example analysis show that the initial stiffness, yield strength, ultimate force, unloading stiffness, residual displacement, ductility and energy dissipation of the member are predicted well. It shows that the MFBFE unit simulates the nonlinear analysis of the seismic response of the shear wall with higher accuracy. The trend analysis of MFBFE unit under different axial compression ratios, different aspect ratios, different concrete strengths, different longitudinal reinforcement ratios, different restraint zone lengths and different stirrup ratios were carried out. The data show that the analytical model presented in this paper is applicable to a wide range of fields and satisfies the accuracy requirements under the above different calculation and construction conditions.