设防烈度地震下内外双重张弦网壳弹塑性地震响应分析

Analysis on elasto-plastic responses of double inner and outer latticed shell string structure under fortification intensity earthquake

基于10个算例模型,对内外双重张弦网壳结构在设防烈度地震下的弹塑性响应特点进行考察,分析跨度、初始预张力、下部结构形式、支座连接条件、矢跨比以及内弦支结构尺寸等因素的影响.采用非抗震荷载工况设计内外双重张弦网壳模型的杆件截面,根据满应力对截面进行优化,并满足小震验算.采用三向人工波及非线性时程法对内外双重张弦网壳进行弹塑性地震响应分析.基于计算结果,统计了7度、8度设防烈度地震作用下上部网壳杆件塑性变形的发展特点及其分布区域.研究表明,模型在7度中震下未出现塑性杆件,部分模型在8度中震下出现一定数量的塑性杆件,分布区域与支座连接形式有关,大部分塑性杆件均出现在最外圈环向梁处.跨度、下部结构形式以及支座连接条件对内外双重张弦网壳的弹塑性响应影响最大.

Based on 10structural models,the elasto-plastic dynamic responses of double inner and outer latticed shell string structure under fortification intensity earthquake are investigated.The effects of span,initial pretension,layout of substructure,connection condition of support,rise-span ratio and size of inner latticed shell string structure are analyzed.The cross-sectional size of members in the 10structural models is determined by the structural full-stress design under non-seismic load cases,and also satisfied by the check of frequently occurred earthquake.Structural elasto-plastic dynamic responses under fortification intensity earthquake are analyzed by nonlinear time-history method.A three-direction artificial earthquake wave generated by code response spectrum is adopted.Based on the calculation results,the characteristics and distributions of plastic deformation of the upper latticed shell string structure under 7and 8degree fortification intensity earthquake are analyzed.Results show that plastic members do not occur under 7 degree fortification intensity earthquake.A certain amount of plastic members exist in 7structural models under 8degree fortification intensity earthquake.The distribution of plastic members is closely related to the connection condition of support.Most of the plastic members occur at the outermost annular beam.Initial pretension,span and layout of substructure are three major factors influencing the elasto-plastic dynamic response of double inner and outer latticed shell string structure.