考虑地震动多点激励与材料应变率效应的主跨300m级独塔斜拉桥弹塑性分析

Study on steel strain-rate and multiple earthquake motions effect on elasto-plasticity responses of 300m span single tower cable-stayed bridge

建立主跨300m级独塔斜拉桥MIDAS/Civil空间有限元模型,开发Civil 2MARC可视化接口程序,进而将MIDAS/Civil模型转入MSC.MARC程序中并检验了模型转化前后的一致性。然后,开发了基于地表功率谱的地表多点地震动生成理论的多点地震动可视化软件MEMS_b(Multiple Earthquake Motions Simulation b)。进而说明了适用于多点位移-速度计算模型的相对精确性和容易实现的优势,并与MSC.MARC程序相结合应用于该桥梁的多点激励分析。最后分析了该桥梁地震作用下的薄弱环节与弹塑性反应,并研究多点输入和材料率效应对桥梁地震反应的影响规律。结果表明:(1)开发的可视化接口程序Civil2MARC界面便于操作,运行稳定,转化高效且结果可靠;(2)开发的可视化多点地震动生成程序MEMS_b界面友好,参数设置灵活且结果有效;(3)位移-速度多点计算模型理论完备,并可通过MSC.MARC程序对位移-速度多点计算模型加以实现;(4)解释并给出了应变率效应和多点地震动对该斜拉桥的塑性铰首次出现时间、位置以及计算末态塑性铰分布的影响规律。本文涉及到理论模型、程序开发及应用计算,可为相关工程提供参考。

Firstly ,the 3D finite element model of single tower cable-stayed with a main span of 300 m is established using software MIDAS/Civil .A visual interface program named Civil2MARC for transfor-ming the finite model from MIDASCivil to MSC .MARC is developed ,and then the MIDAS model is transformed to MSC .MARC using the Civil2MARC .The consistency between the MIDAS and MARC fi-nite model is compared to verify the accuracy of the interface program Civil2MARC .While ,a visual pro-gram named MEMS_b is developed based on power spectra of ground is briefly introduced here .Further , the advantage of the displacement-velocity model is explicitly addressed ,and the model is further applied to the cable-stayed bridge through the software MSC .MARC .Finally ,to study the influence of multi-supported ground motions and material strain-rate on seismic response under earthquake motions ,the subroutine considering strain-rate effect of steel and concrete is used to analyze the dynamic responses in-cluding weak parts ,elasto-plastic response and so on .The results show that （1） The visual program Civ-il2MARC developed in this paper is characterized with convenient operation ,stable running ,high effi-cient transforming process and reliable transforming results .（2） The visual program MEMS_b developed in this paper has friendly user interface ,flexible assignment and direct post-processing results display . （3） the displacement-velocity model is more reasonable and can be easily complemented through MSC . MARC .（4） The influence law strain-rate and multi-point earthquake motions effect on the plastic hinges occurrence location ,time and final distribution of the cable-stayed bridge is analyzed and given .T his pa-per involves theory model ,program developing and engineering numerical computation ,and can provide reference for revlevant engineering .