抗震销在上海莘庄立交工程的设计中,由于构造的特殊性,其力学特性难以用常规方法表达。基于位移和多级设防的抗震思想,以莘庄立交工程中的一异型板桥为例,首次以两个包含极端边界条件的结构分析模型考虑抗震销这一特殊构造措施对结构的影响,并按照实际结构构造充分考虑材料非线性及连接构件的非线性等因素,分别以弹塑性纤维梁柱单元、空间滑动支座单元和接触单元模拟桥墩屈服、支座滑动、相邻结构之间碰撞,建立了空间非线性时程反应分析模型,并进行了设计和罕遇地震水平两个概率水准下的地震反应分析和抗震性能评估,并根据分析结果的对比,提出强化抗震销刚度的建议。
In Xinzhuang interchange bridge engineering design, the mechanic characteristics of antiseismic bolts are difficult to symbolize by usual ways due to their special construction. In the light of seismic resistant design conception based on deformation and multi-failure criteria, by simulating the antiseismic bolt with two structural analysis models including ultimate boundary conditions and considering material and contact nonlinear properties according to practice in detail, pier yielding, bearing sliding and pounding between adjacent structures are simulated by elasto-plastic fiber beam-column element, sliding bearing element and contact element, respectively. The model is built up for three dimensional nonlinear time history analysis under the background of a heteromorphic bridge in Xinzhuang interchange engineering. The nonlinear time history analyses and estimations of seismic performance are carried out under design and severe level earthquake by using this model and a suggestion for strengthening stiffness of antiseismic bolts is made on the basis of comparing the analysis results.