【作者】 芦燕；

【导师】 韩庆华；

【作者基本信息】 天津大学 ， 结构工程， 2009， 硕士

【摘要】 大跨度拱形立体桁架结构作为空间结构的一种结构形式,该结构体系在火车站无站台柱雨棚中得到广泛应用的同时,在其他公共建筑中也有一定的发展空间。大型公共建筑的局部或整体结构的倒塌事故时有发生,其造成的人员财产损失巨大。目前针对大跨度拱形立体桁架结构体系的研究只限于静力分析及地震作用的动力响应研究,而强震作用下该结构的倒塌破坏机理却鲜有文献报道。本文对强震作用下大跨度拱形桁架结构体系的动力强度破坏进行研究,获得拱形立体桁架结构有关塑性发展和动力强度破坏行为的认识,建立动力强度破坏准则,为大跨度拱形立体桁架结构体系的应用推广,结构的抗震性能理论研究提供重要参考。本文以北戴河火车站无站台柱雨棚的单榀拱形立体桁架结构为例,选取三向Elcentro波和三向天津波为地震输入,进行弹塑性时程分析。随着荷载幅值增加,对结构进入塑性的杆件比例、最大应力杆件的相对塑性应变值以及最大节点位移响应的全过程进行了全面详细的观察。同时,综合考虑了三向地震输入与仅水平输入、不同结构矢跨比、不同桁架高度以及不同桁架柱段高度等因素的影响,对该结构的动力强度破坏进行参数化分析。研究表明:随着荷载幅值增加,结构刚度逐渐弱化;节点振动偏移平衡位置越来越大,但基本上保持比较平稳的振动,位移时程曲线没有突然的发散点;塑性深入的发展使整个结构不断发生内力重分布,结构失去承载能力,这是典型的强度破坏。从结构参数化分析得出:三向地震输入比仅水平向地震输入时结构强度破坏的加速度幅值低;矢跨比对拱形桁架的动力强度破坏的加速度幅值有显著影响。随着矢跨比的增加,动力强度破坏的加速度幅值呈线性下降趋势;桁架高度不同,结构的动力强度破坏的加速度幅值也不同,桁架高度越小,则结构的动力强度破坏的加速度幅值也越低;随着结构桁架柱段高度的增加,动力强度破坏的加速度幅值呈下降趋势,但是影响程度不大。更多还原

【Abstract】 Large-span steel arch truss structure ,as a structural form of spatial structure, has been widely used both in the steel truss design of NO-platform-column Canopy in the railway station and in other public buildings.Part or overall collapse of the large public buildings occurs from time to time, which leads to enormous losses of personnel and property. At present,there is only the study of static analysis and dynamic response of earthquake on the large-span steel arch truss structure and little research on the collapse mechanism under severe earthquakes is made.In this paper the complete dynamic response of the plastic-depth development and the dynamic strength failure modes are investigated,and dynamic strength failure criterion of large-span steel arch truss structure is also given by summary of parameter analysis results.All of this will help the application of this structural form and provide the research theory about structural seismic performance.The large-span steel arch truss structure in Beidaihe Train Station is taken as a case study in this paper.The method of elastic-plastic time-history analysis was employed to evaluate the performance of the structure under severe earthquakes with Elcentro Wave and Tianjin Wave as earthquake input. The plastic element ratio of large-span steel arch truss,relative plastic strain of elements and displacement of the key joint on large-span steel arch truss in pace with the increasing seismic input are investigated.At the same time, a great deal of parameter analysis has been done considering the horizontal and three-dimensional El-Centro wave,the different rise-to-span ratio,the different truss height and the different truss column height.The study indicates that the structure stiffness weaken in pace with the increasing seismic input acceleration.The joint remain steady vibration without the offset of the equilibrium position,and time-displacement curve does not have a sudden point of divergence.Plastic-depth development of the structure leads to the plastic inner force redistribution and the dynamic strength failure. This is very typical strength failure.What’more,a great deal of parameter analysis has been done. It is shown that three-dimensional earthquake wave controls the dynamic strength failure critical loads.Rise-to-span ratio,as the indicator on the dynamic strength failure of the large-span steel arch truss,has a significant influence on the critical load.With the increment of the rise-to-span ratio,dynamic strength failure critical load decreases,and the downward trend is linear.The different truss height causes different dynamic strength failure critical load,that is to say,the lower the truss height is ,the lower dynamic strength failure critical load is. With the increment of the truss column height,there is a downward trend,but the extent is not strong.更多还原