大跨张弦桁架结构整体抗火性能分析  

Analysis on overall fire resistance of long-span truss string structure

作　　者：袁国安 邱国志 YUAN Guo-an;QIU Guo-zhi(Department of Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure,Shanghai 200240,China)

机构地区：[1]上海交通大学土木工程系,上海200240 [2]上海市公共建筑和基础设施数字化运维重点实验室,上海200240

出　　处：《空间结构》2022年第3期49-55,共7页Spatial Structures

摘　　要：以某188m跨张弦桁架结构为分析对象,采用火灾动力学模拟软件FDS模拟了3种火灾作用下的非均匀温度场.考虑高温对钢材及钢索特性的影响,利用有限元软件ANSYS进行了高温下结构整体的非线性分析.研究了在不同火灾作用下的温度场分布特征、结构位移特征、杆件内力特征、钢索预应力损失情况以及抗火薄弱部位.结果表明:火灾下钢构件最高温度出现在火源中心正上方;钢索预应力最大损失为11.7%;火源位于沿结构跨度边缘时对结构影响最大,此时结构耐火时间为1200s,钢构件最高温度可达653℃,结构沿跨度边缘区域杆件为抗火薄弱部位.建议对结构抗火薄弱部位采用喷涂防火涂料或增大杆件截面面积的方法来延长结构抗火时间.Based on a truss string structure with a span of 188 m,the non-uniform temperature field under the action of three kinds of fire is simulated by the fire dynamic simulation software FDS.A nonlinear analysis on the overall fire resistance of truss string structure considering the influence of high temperature on the steel and wire rope is conducted through the finite element software ANSYS.Distribution characteristics of the temperature field,displacement properties of the structure,internal force characteristics of member,the cable prestress loss and the most unfavorable position are studied under different fire.The results show that the highest temperature of steel member appears directly above the center of fire.The maximun loss of cable prestress is 11.7%.When the fire source is located along the edge of the structure span,it has the greatest impact on the structure.In this case,the fire resistance time of the structure is 1200 s,the maximum temperature of the steel member can reach 653℃,and the member along the edge of the span are the weak part for fire resistance.It is suggested to extend the fire-resistant time of the structure by spraying fireproof coating or increasing the cross section area of the rod.

关 键 词：大跨张弦桁架结构 火灾 非线性有限元分析 整体抗火性能 

分 类 号：TU393.3[建筑科学—结构工程]