【作者】 孙伟苹；

【导师】 李海旺；

【作者基本信息】 太原理工大学 ， 结构工程， 2012， 硕士

【摘要】 大跨度钢管拱桁架因其结构形式灵活多样、造型优美、受力合理、用钢量省等优点,被广泛应用于火车站、飞机场、体育馆、会展中心等大型公共建筑中,在大震发生后还可以作为临时避难场所。然而目前针对大跨度钢管拱桁架在强震作用下的动力响应理论研究成果较少,因此本文对钢管拱桁架结构进行强震作用下的动力弹塑性分析,得出该结构的塑性发展规律和失效机制,为今后该体系的抗震性能研究提供参考。本文以跨度180m矢跨比0.2三心圆钢管拱桁架结构为研究对象,在已有钢管拱桁架动力响应研究成果基础上,主要展开了以下几方面工作：首先,采用有限元分析软件SAP2000分别选用宁和波、LOMA波、上海人工波对模型进行动力弹塑性分析,研究中通过逐渐增加结构的地震加速度峰值,并对结构模型最大节点的位移、杆件进入塑性的比率、杆件的塑性变形程度全过程进行了详细的考察,确定结构在每种地震波作用下的破坏界限加速度峰值和位移延性系数,得出结构的失效机理和破坏形态。其次,选用Q345、Q390和Q420三种不同强度钢材对结构进行动力弹塑性分析,对比它们在相同设防烈度下设计所需用钢量、在地震作用下的弹塑性界限加速度峰值、破坏界限加速度峰值和位移延性系数等,总结这些数据随着钢材强度提高的变化趋势。研究所得结论主要有以下几点：1、钢管拱桁架在地震作用下,最大节点位移随着地震加速度峰值增大缓慢增加,最终结构发生强度破坏。2、选用不同地震波对钢管拱桁架进行动力弹塑性分析,得出结构在X向地震作用下的弹塑性界限加速度峰值相差9.68%-98%,在Z向地震作用下相差12.5%-47.54%,在X+Z向地震作用下相差14.81%-93.75%；结构在X向地震作用下得到的破坏界限加速度峰值相差20%-65.52%,在Z向地震作用下相差1.56%-30%,在X+Z向地震作用下相差10%-35.8%；结构在X向地震作用下得到的位移延性系数相差1.53%-14.5%,在Z向地震作用下相差9.92%～16.41%,在X+Z向地震作用下相差5.78%-44.91%；表明采用不同的地震波对结构进行动力弹塑性分析结果相差较大3、对采用不同钢材强度的钢管拱桁架进行动力弹塑性分析,结构采用Q390钢材单榀用钢量比Q345减少6.74%,采用Q420钢材比Q345减少11.75%；结构采用Q390钢材弹塑性界限加速度峰值比Q345提高20%左右,采用Q420比Q345提高30%左右；结构采用Q390钢材破坏界限加速度峰值比Q345提高15%左右,采用Q420比Q345提高25%左右；上述数据表明随着钢材强度的提高,钢管拱桁架用钢量逐渐减少,而其弹塑性界限加速度峰值和破坏界限加速度峰值显著增大,说明采用高强度钢材可显著提高结构的抗震水平。更多还原

【Abstract】 Large-span steel pipe arch truss is flexible and elegant, reasonable force and the less amount of steel and so on, so it has been widely used in train stations, airports, stadiums, exhibition centers and other large public buildings, as well as to provide a safe refuge after strong earthquake. However, there is the less dynamic response research results on large-span steel arch truss under strong earthquake. In this paper, the dynamic elasto-plastic analysis on steel arch truss under strong earthquake is investigated, and the law of plastic development and collapse mechanism of the structure are given, which provide research theory about structural seismic performance.In this paper, the180m-span and0.2-rise to span ratio steel arch truss is studied. Based on the existing dynamic response research results on steel arch truss, the paper launched the following work:Firstly, the dynamic elasto-plastic analysis was taken by inputing NH wave, LOMA wave and Shanghai RG wave with finite element analysis software SAP2000. Maximum displacement of nodes, the plastic element ratio of structure, the plastic deformation of element in pace with the increasing seismic input are investigated to gain failure critical acceleration, Maximum yield-displacement ratio, failure mechanism and failure modes of structure.Secondly, the dynamic elasto-plastic analysis was taken with three different strength steel of the Q345, Q390and Q420. The data such as amount of steel designed in the same fortification intensity, the elastic-plastic critical peak acceleration, failure critical peak acceleration and displacement ductility index are compared, and the trend of these data with the increased strength of steel are summed up.By calculation and analysis, it takes the following conclusions:1. The Maximum displacement of nodes increases slowly with earthquake peak acceleration increasing, and the steel arch truss under the earthquake occurs strength failure finally.2. The dynamic elasto-plastic analysis was taken under three different seismic waves. The elastic-plastic critical peak acceleration is different from9.68%to98%under X direction seismic waves,12.5%to47.54%under Z direction seismic waves and14.81%to93.75%under X+Z direction seismic waves. The failure critical peak acceleration is different from20%～65.52%under X direction seismic waves,1.56%～30%under Z direction seismic waves and10%～35.80%under X+Z direction seismic waves. The displacement ductility index is different from1.53%～14.50%under X direction seismic waves,9.92%～16.41%under Z direction seismic waves and5.78%～44.91%under X+Z direction seismic waves.3. The dynamic elasto-plastic analysis was taken with three different strength steel. The amount of Q390and Q420steel is reduced respectively by6.74%and11.75%compared with Q345. The elastic-plastic critical peak acceleration of Q390and Q420steel is increased respectively by about20%and30%compared with Q345. The failure critical peak acceleration of Q390and Q420steel is increased respectively by about15%and25%compared with Q345. It is indicated that the amount of steel is reduced gradually, but the elastic-plastic critical peak acceleration and failure critical peak acceleration increases greatly with the improvement of the strength of steel. Therefore, the seismic level of steel pipe arch truss is improved by high-strength steels.更多还原