【摘要】 在钢筋混凝土结构的非线性反应分析中,地震动通常简化为沿结构的主轴方向输入,地震波的最不利输入方向问题经常被忽略。以三个规则、对称的钢筋混凝土典型空间框架为例,在OpenSees平台上,采用基于柔度法的纤维模型从而更加真实地模拟柱在双向弯曲和变化轴力作用下的非线性反应,通过多角度输入地震波对各框架进行了罕遇烈度水准下的非线性反应分析。结果表明,规则、对称空间框架的柱端出铰率、混凝土纤维压应变以及钢筋纤维拉应变的地震动最不利输入方向是45°、135°,梁端出铰率、纤维应变、转角延性的最不利方向为主轴方向,柱端转角延性的地震动最不利输入方向不明显,仅沿结构主轴方向输入地震波无法得到最不利的塑性耗能特征。更多还原

【Abstract】 In the nonlinear responses analysis of reinforced concrete structures,seismic wave input angles are usually simplified as paralleling to the principal axis of structures,and the problem of critical excitation angle is generally ignored.In this paper,three regular and symmetrical reinforced concrete typical spatial frames were employed as examples.Based on the OpenSees framework,flexibility method based fiber model was adopted to simulate the nonlinear responses of the columns under biaxial bending and varying axial forces.Nonlinear dynamic response analyses of the three frames under rare earthquake excitations with varying seismic wave input angles were carried out.The results show that for the regular and symmetrical spatial frames,the critical excitation angle of compressive strain of concrete fibers,tensile strain of steel fibers and ratio of plastic hinges at column ends are 45° and 135°,the critical excitation angle of strain of concrete fiber and steel fiber,ratio of plastic hinges and rotation ductility at beam ends are principal axis of structures.The critical excitation angle of rotation ductility at column ends is not apparent.It cannot get critical energy dissipation characteristics of plastic hinges if seismic wave was input along the principal axis direction.更多还原