大跨度悬臂桁架结构的强震失效机理及抗震性能评估的分析研究.pdf

Classified Index: .: Dissertation for the Master Degree in Engineering THE FAILURE MECHANISM AND SEISMIC EVALUATION OF LONG-SPAN CANTI- LEVER TRUSS STRUCTURE UNDER EARTHQUAKES Candidate : Qi Chunlin g Supervisor : Prof. Fan Feng Associate Supervisor: Assoc. Prof. Zhi Xudong Academic Degree Applied for : Master of Engineering Specialty : Structural Engineering Affiliation : School of Civil Engineering Date of Defence : July, 2010 Degree-Conferring-Institution : Harbin Institute of Technology 哈尔滨工业大学工学硕士学位论文 I 摘要大跨度悬臂桁架结构外观简洁,形式富于多变,具有良好的受力性能和经济指标,在实际工程中应用较为普遍。虽然该结构目前已有广泛的应用,但它在强震作用下的响应规律及失效机理研究目前尚属空白。本文正是在这样的背景下,对悬臂桁架结构在强震下的失效机理进行了较为系统的研究,研究结论可为悬臂桁架在抗震区的应用提供参考。首先,本文对悬臂桁架的自振特性进行了研究。重点分析了悬臂桁架结构的振型模态特点,通过对 20m 、 30m 、 40m 三种跨度悬臂桁架结构的大规模参数分析,讨论了结构的自振频率随杆件截面应力比、屋面质量、高跨比和跨度等参数的变化规律。其次,研究了悬臂桁架结构的强震失效机理。本文通过对悬臂桁架结构典型算例的分析,总结了该结构在强震作用下的响应特点,根据结构的整体变形、不同屈服程度杆件的发展等多项特征响应确定了结构为动力强度失效模式。本文还分析了考虑材料损伤累积和初始几何缺陷等因素对结构的动力响应的影响。通过对大量算例计算结果的统计总结,分析了结构随几何参数或荷载参数变化的强震响应规律。最后,本文对悬臂桁架结构的抗震性能进行了评估。详细介绍了基于性能的抗震评估方法——增量动力分析( Incremental Dynamic Analysis , IDA )的基本原理和具体实施步骤,阐述了 IDA 方法相关参数的确定原则,并利用该方法对悬臂桁架结构进行了有效的抗震性能评估,从概率的角度评价了悬臂桁架结构在未来遭遇地震时的可靠性。关键词: 悬臂桁架;强震作用;动力强度失效;抗震性能评估; IDA 哈尔滨工业大学工学硕士学位论文 II Abstract The long-span cantilever truss structur e can have simple shapes and diverse forms of structures. It is economically efficient and behaves excellently as an engineering structure. However, although it is widely used in constructions, its responses to severe earthqu akes and corresponding fa ilure mechanisms are not thoroughly understood. The research in th is thesis is carr ied out in such a background that re lated researches in th is field are rare a nd further studies are needed to provide references for applicati on in high-risk areas, making a systematic analysis of the failure me chanisms of cantilever truss structure subject. Firstly, analysis of the free vibrantion characteristics of cantilever truss structure is made. The m odes of v