支承形式对正放四角锥网架抗火性能的影响  

Fire-Resistant Behavior of Square Pyramid Space Trusses under Different Support Conditions

作　　者：孙伟建[1] 高轩能[1] 张惠华[1] 

机构地区：[1]华侨大学土木工程学院,福建厦门361021

出　　处：《华侨大学学报（自然科学版）》2013年第4期444-448,共5页Journal of Huaqiao University(Natural Science)

基　　金：国家自然科学基金资助项目(51278208);福建省科技计划重大项目(2012Y4010);中央高校科研业务费专项基金资助项目(JB-JC1005)

摘　　要：采用ANSYS非线性有限元分析软件,建立正放四角锥网架在高大空间火灾作用下的热-结构耦合有限元计算模型.考虑边界不同支座弹簧刚度的影响,对该模型在火灾均匀温度场中的全过程反应进行数值模拟计算,同时研究均匀升温条件下杆件的内力变化情况.结果表明:采用不同支承形式时,无论法向弹簧刚度多大,周边支承形式的网架结构临界温度均最高,具有更优越的抗火性能;采用同种支承形式的正放四角锥网架时,其法向弹簧刚度越大,临界温度越高;在升温过程中,法向弹簧刚度大小对同一上弦杆内力影响较小;均匀升温条件下,各上弦杆件内力呈现出由角部向跨中先减小后逐渐增大,沿网架边界由角部向中间逐渐减小的变化趋势,随着弹簧刚度的增大,内力最大杆的位置由角部转移到跨中.To investigate the fire-resistant behavior of square pyramid space trusses under different support conditions,a numerical fire-structure coupling analysis model under the large space fire was established by the nonlinear finite element software ANSYS.Considering the influence of different constraint sping stiffness,the whole process response of square pyramid space trusses in uniform temperature field was simulated,and the internal forces were calculated.The numerical results show that the square pyramid space trusses with surrounding support conditions has the highest critical temperature irrelevant to the value of spring stiffness,which shows superior fire-resistant behavior;and the critical temperature of square pyramid space trusses increases with increasing the spring stiffness for a certain support condition.The spring stiffness influences slightly the internal force of a same upper chord during the temperature increment.Under uniform temperature field,the internal force of upper chords presents a tendency of the initial decrease,but increase after reaching a minimum from the corner to the span centre;and presents a tendency of gradual decrease along the boundary from the corner to the middle position.The position of the upper chord member with maximum internal force is transferred from the corner to the span center with increasing the spring stiffness.

关 键 词：正放四角锥网架 抗火性能 支承形式 弹簧刚度 温度场 数值模拟 

分 类 号：TU356[建筑科学—结构工程]