摘要
以跨度150m、矢跨比0.25的钢拱桁架结构体系为研究对象,基于四种场地类别分别建立四种模型,运用SAP2000软件和集中塑性铰理论,进行在地震波作用下的动力弹塑性性能分析.分析中考虑了几何和材料双重非线性影响,分别获得了结构在不同场地类别下的失效承载力、节点位移响应、位移延性系数、塑性发展程度以及结构整体变形形态.结果表明:按多遇地震作用设计,场地由硬变软,用钢量变化很小,按满足罕遇地震下安全工作的性能要求进行设计,用钢量变化较大;在不同地震波作用下,拱桁架多因靠近跨中与拱脚附近的腹杆首先退出工作导致结构失效破坏;不管场地硬或软,结构失效时塑性发展程度均较浅,进入塑性的杆件数量均较少,最终破坏是由"薄弱部位"形成塑性铰区域导致结构成为机构而倒塌;场地由Ⅰ类到Ⅳ类变化时,对应结构失效界限地震波峰值的比值为1∶0.802∶0.766∶0.721.
The model used in this paper features an arch truss with a span of 150m and the rise to span ratio as 0.25. Four structures based on the model and four site conditions were built incorporating concentrated plastic hinge theory and SAP2000 software. An elastic-plastic time history analysis on the four structures under different earthquake waves is carried out. In the analysis, both geometric and material nonlinear effects are taken into consideration. Failure of the structure bearing capacity, node displacement responses, structural ductility coefficient, its plastic development degree, and the deformation mode under different site conditions are obtained. In the flexible design stage, when site conditions change from hard to soft, the steel consumption of structure changes slightly. When the design meets the performance security work under rare earthquake requirements, the steel consumption of structure have a major change. Under different seismic waves, damages of arch truss structure are usually caused by early exit of the web member near the span center and the arch foot. No matter under what kind of site conditions, when the structure fails, its plastic development degrees are all shallow and the bars which enter the plastic stage are few. The reason of structural failure is that the ＂weakness＂ becomes the plastic hinge region which leads to structural mechanism. When site conditions change from hard to soft, the ratio of the seismic wave peaks when the structure failure occurs is 1 ：0. 802 ：0. 766 ：0. 721.
出处
《空间结构》
CSCD
北大核心
2015年第3期42-48,共7页
Spatial Structures
基金
国家自然科学基金项目(50878137)
山西省科技攻关项目(20080321086)
山西省回国留学人员科研资助项目(2009-26)
关键词
空间拱桁架
场地条件
动力弹塑性
抗震性能
地震波
spatial arch truss
site condition
elastic lastic
earthquake resistance
seismic waves
