大空间建筑不同区域受火对平面张弦梁结构响应影响分析  

The Structural Response of Beam String Structure in Case of Fire in Different Areas of a Large Space Building

作　　者：陈长坤[1,2] 刘广林[1] 张冬[1] 

机构地区：[1]中南大学土木建筑学院防灾科学与安全技术研究所,长沙410075 [2]中国科学技术大学火灾科学国家重点实验室,合肥230027

出　　处：《科技导报》2011年第12期32-36,共5页Science & Technology Review

基　　金：中国科学技术大学火灾科学国家重点实验室开放课题(HZ2009-KF05)

摘　　要：为了获取大空间建筑火灾下张弦梁结构响应规律,分析不同区域受火对该结构响应影响,优化结构抗火设计方法,本文结合大空间建筑特点及火灾特征,考虑张弦梁结构边跨受火、跨中受火及结构全跨整体受火情况,采用有限元法对3种受火条件下的结构响应展开研究,探讨了该结构在火灾高温下的行为响应及不同区域受火对结构响应影响,获取了火灾高温下活动铰支座的侧向位移、拱梁的竖向位移、下弦索的轴向拉力、撑杆的轴向压力,进而提出了适合大空间张弦梁结构抗火设计的优化建议。结果表明,受火灾高温影响,结构变形,右端可动铰支座随拱梁温度升高逐渐向右移动,且幅度较大,为提高结构的安全性能,建议采取一定的措施限制活动铰支座水平位移最大变化量;对比不同工况下结构位移、弯矩及轴力变化,可知不同区域受火致使空间温度场分布不均,该因素对张弦梁结构响应影响较大,张弦梁结构抗火性能研究应予以考虑;基于整体受火条件的结构抗火设计过于保守,缺乏针对性,结构抗火设计应结合实际火灾场景,考虑局部区域受火情况探讨结构行为响应,针对张弦梁结构防火的薄弱部位采取针对性的隔热或防火措施。In this paper,the structural response of the Beam String Structure（BSS） in case of fire in a large space building is investigated by using the finite element method.The fires at the side segment,the middle segment and the full span of the BSS are considered separately in order to reveal the impact of fire areas on the structural response.The horizontal displacement of the right support block and the vertical displacement of the beam are obtained,together with the axial forces of the string and strut.The results indicate that the right support block of the BSS exposed to fire would move toward right with the increase of the fire temperature gradually in a notable extent.It is recommended that some measures should be taken to limit the maximum horizontal displacement of the right support block for improving the safety of the structure.The non-uniform temperature caused by different fire exposures may greatly influence the displacement,bending moment and axial force of the structure.This should be considered in the fire resistant design for this structure.A fire protection design for the BSS based on the assumption of its full span being exposed to fire is relatively conservative.The real fire condition should be considered during the fire resistant design and extra protecting measures should be taken for the weaker members and segments based on the analysis on the structure response of the BSS under some local fire condition.

关 键 词：张弦梁结构 大空间建筑 火灾 结构抗火性能 

分 类 号：TU399[建筑科学—结构工程]