大跨桁架体系的连续性倒塌分析与机理研究  

PROGRESSIVE COLLAPSE ANALYSIS AND MECHANISM STUDY FOR LARGE-SPAN STEEL TRUSS STRUCTURES

作　　者：江晓峰[1,2] 陈以一[2] 

机构地区：[1]华东建筑设计研究院有限公司,上海200002 [2]同济大学土木工程学院,上海200092

出　　处：《工程力学》2010年第1期76-83,共8页Engineering Mechanics

基　　金：教育部高等学校博士学科点专项科研基金项目(20060247034)

摘　　要：在突发事件的直接影响下,结构的局部构件可能首先发生初始破坏并进一步导致结构的连续性倒塌。与框架结构或承重墙体系相比,大型公共建筑中普遍采用的桁架体系具有冗余度较低的特点,为提高其结构鲁棒性,必须在详细分析基础上采用不同的设计策略。该文以钢屋架体系为例,通过连续性倒塌过程的数值分析,研究了内力重分布过程、动力效应和主要破坏模式等问题;根据局部杆件失效后的结构特性,归纳出转动铰机制、滑移面机制和长压杆机制等三种基本的局部内力重分布机制;结合简化数学模型的理论分析,阐述了敏感构件和关键构件的概念,为该类结构的安全性评价提供了一种简便的尺度。Initial failure of local elements caused by accidental events may become a starting point of progressive collapse. Diferring from moment frames or bearing wall systems, the truss system widely used in public architectures with large-span is of low redundancy in nature. In order to raise its structural robustness, precise analysis and therefore valid design trategy shall be expected. As a case study, a steel truss roof is deeply investigated in this paper by numerical method, and the internal force redistribution after intial failure, dynamic effect and primay failure modes are studied. By post-intinial failure analysis, it is found there are three kinds of redistributary mechanisms for truss structure： rotation pin mechanism, sliding surface mechanism and long column mechanism. The concept of sensitive element and key element is conceived according to simplified mathematic models, which provides a simple measure to evulate the safety performance for such structural system.

关 键 词：钢桁架体系 连续性倒塌 数值模拟 内力重分布 敏感构件 关键构件 

分 类 号：TU312.3[建筑科学—结构工程] TU318.1