新旧规范下梁式桥抗震分析对比的研究.pdf

I摘要梁式桥是一种常见的桥梁形式,在我国的桥梁建设中占据了主要地位,这同时决定了其在我国桥梁抗震加固中所占的比例,这在我国2008年5月发生的汶川大地震中就有充分的体现。我国于2008年10月颁布了新的桥梁抗震设计规范——《公路桥梁抗震设计细则》(JTG/T B02-01-2008),取代了原有《公路工程抗震设计规范》(JTJ 004-89)中的桥梁抗震设计部分,新规范吸纳了基于性能的抗震设计思想,采用了不同于旧规范的参数取值,而大部分现有桥梁都是按照旧规范进行抗震设计的,因此,进行梁式桥在新旧规范下的抗震分析比较研究对于梁式桥的抗震加固设计具有重要的实践意义和实用价值,本文所做的工作正是在这种背景下开展的。本文以选取广泛使用的连续梁桥和连续刚构桥为研究对象,利用大型通用有限元分析软件ANSYS建立全桥模型,分别基于新旧抗震设计规范,考虑桩-土-结构相互作用对桥梁地震响应的影响,采用反应谱方法对其进行抗震分析,对连续梁桥和连续刚构桥在不同设计理论和不同边界条件下对地震响应的异同做出一定的研究。基于以上分析结果,本文主要得出了如下结论:1、桩-土-结构相互作用会使结构变柔,周期变长,对于刚性较小的地基影响更加显著,甚至会改变桥梁结构的振型形状与次序,因此当地基刚度较小时应该考虑桩-土-结构相互作用的影响。2、新规范对于桥梁结构对地震的响应能力的要求比旧规范大大提高,宜采用新规范对现有受损桥梁进行抗震加固设计。本文得出的这些结论可为梁式桥的抗震加固设计提供一些有用的参考。关键词:梁式桥连续梁桥连续刚构桥抗震设计桩-土-结构相互作用IIAbstractAs mon bridge style, beam bridges have occupied a dominate position in the bridgeconstruction of our country, determiningtheirgreatamount in the bridgesthat needseismic retrofitting design, which can be reflectied in the bridge damages of WenChuan Earthquake happened on May 12th, new code—Guidelines for Seismic Design of Highway Bridges(JTG/T B02--2008) has been publishedinOct,2008, replacing the corresponding part of the old one—Specifications of Earthquake Resistant Design for Highway Engineering(JTJ 004-1989).The New code uses parameters different from the old code, and performance-based seismic design theroy is introduced. While a majority of existing brdiges is designed based on the old code, therefore, it has important practicalsignificance and applied value for bridge seismic retrofitting design todo some research on the seismic design of beam bridgesby drawing parison between the new code with the old one. The thesis is plished in the very author takesthe widely used continuous bridge and continuous rigid-frame bridge for example,uses ANSYS to establisha model of the whole bridge and make seismic analysis through response spectrum method, based on the new and old code for bridge seismic design, taking pile-oil-structure interaction into consideration, researche