【作者】 李宇；

【导师】 杨庆山； 朱晞；

【作者基本信息】 北京交通大学 ， 桥梁与隧道工程， 2010， 博士

【摘要】 在强震作用下,桥梁会因弹塑性变形而产生较大的残余位移,这就使得结构即使未发生倒塌破坏,也会因较大的残余位移而不能使用或修复。而土—结构相互作用的问题,由于地基土参数的不确定性和基础形式的多样性,一直以来都是桥梁抗震研究中的难点。因此,本文针对目前我国桥梁结构的抗震设计和性能评估方法中存在的不足,在总结和吸取以往国内外学者研究成果的基础上,以多自由度全桥结构和等效单墩模型为对象,就考虑残余位移影响的桥梁结构基于性能的抗震设计方法、考虑土—结构相互作用的桥梁结构抗震性能评估方法进行了系统的研究。主要研究工作如下：1.研究了土—结构相互作用对高柔桥墩弹塑性地震响应的影响,并对弹塑性反应谱进行了参数影响研究,从而建立了与《铁路工程抗震设计规范》相符的弹塑性反应谱。(1)建立了考虑地基柔性效应的高柔桥墩分析模型,研究了土—结构相互作用对高柔桥墩弹塑性地震响应的影响；(2)依据我国现行的《铁路工程抗震设计规范》,选取了四类场地的320条强震记录,系统地研究了地震动特性及恢复力模型动力参数对弹塑性反应谱的影响,进而为弹塑性反应谱的建立提供了指导依据；(3)建立了与《铁路工程抗震设计规范》相符的弹塑性加速度谱、弹塑性位移谱和残余位移谱,进而为考虑残余位移影响的桥梁结构基于性能的抗震设计方法的提供了设计谱依据。2.系统地研究了单自由度系统和多自由度桥梁结构的地震能量响应及其分配规律,从而建立了与《铁路工程抗震设计规范》相符的能量反应谱。(1)利用所选取的四类场地320条强震记录,采用非线性能量反应时程分析法,系统地研究了地震动特性及恢复力模型动力参数对单自由度系统地震能量响应及其分配规律的影响,为能量反应谱的建立提供了指导依据；(2)对考虑土—结构相互作用的客运专线双柱式桥墩进行了地震能量响应分析,研究了多自由度桥梁结构的地震能量响应及其分配规律；(3)建立了与我国现行的《铁路工程抗震设计规范》相符的地震总输入能量谱、滞回耗能谱等,进而为正规化累积耗能参数的研究以及桥墩结构基于能量的抗震验算方法提供了相应的谱依据。3.提出了考虑残余位移影响的桥梁结构基于性能的抗震设计方法,并改进了桥墩结构基于能量的抗震验算方法。(1)基于改进的Park-Ang双参数地震损伤评估模型,统计回归了四类场地的正规化累积耗能参数,得到了基于损伤性能指标的等效位移延性系数；在此基础上,以损伤指标作为性能指标,将等效位移延性系数、弹塑性位移谱和残余位移谱相结合,提出了考虑残余位移影响的桥梁结构基于性能的抗震设计方法,给出了具体的算例,并采用非线性时程分析法验证了本文所提出的抗震设计方法的可行性；(2)利用所建立的地震总输入能量谱和滞回耗能谱,对桥墩结构基于能量的抗震验算方法进行了改进,并将它应用于桥墩的设计实例中。4.针对我国的桥梁结构,提出了改进的简化能力谱法以及能够考虑土—结构相互作用的脆弱性分析方法。(1)建立了与我国现行的《铁路工程抗震设计规范》相符的弹塑性需求谱和强度折减系数谱,并结合ATC-40和FEMA356能力谱法的优点,提出了改进的简化能力谱法,并用客运专线双柱式桥墩工程实例检验了改进方法的计算精度；(2)以客运专线双柱式桥墩为研究对象,验证了将FEMA440考虑土—结构相互作用的能力谱法应用于我国桥梁工程抗震性能评估的可行性。(3)将FEMA440中考虑土—结构相互作用的能力谱法与结构脆弱性分析相结合,提出了综合考虑地基柔性效应、运动学效应和基础阻尼效应的桥梁结构脆弱性分析方法,并以此建立了城市高架桥的脆弱性曲线,进而与不考虑土—结构相互作用所得的计算结果进行了对比,验证了本文方法的优越性。5.改进了ATC-40和FEMA356中考虑多振型效应的非线性静力分析方法。在此基础上,将改进的非线性静力分析方法与结构脆弱性分析相结合,应用于考虑土—结构相互作用的高墩大跨桥梁结构的抗震性能评估中,研究了多振型效应对高墩大跨桥梁结构脆弱性分析的影响。更多还原

【Abstract】 Residual displacement could be generated due to the elasto-plastic deformation of bridge subjected to strong ground motion. As a result, bridge will be out of commission or unrepairable even though the collapse of bridge doesn’t happen. Morever, because uncertain foundation soil parameters and various foundation styles, problem about siol-structure interaction is the difficuty of seismic desigen study at all times. Consequently, according to the current shortages in the seismic design and evaluation for bridges, some important ploblems are systemically studied in this paper, including performance-based seismic design considering residual displacement, seismic evaluation method considering soil-structure interaction effects. The principle contents are as follows:1. Effect of soil-structure interaction on the elasto-platic seismic response of tall and slender pier is studied. Moreover, parametric study on elasto-platic response spectra is done in order to establish elasto-platic spectra which can be in accord with Seismic Design Code for Railway Engineering. (1) By establishing an analytical model considering flexiable foundation effects, nonlinear time history analysis is carried on to study the effects of soil-structure interaction on the elasto-plastic response of tall and slender pier. (2) According to the applicable Seismic Design Code for Railway Engineering,320 strong motion records of four sites are chosen. And parametric study on elasto-plastic response spectra is done by considering parameters of earthquake motion and restoring model. (3) Elasto-plastic acceleration spetra, elasto-plastic displacement spetra and residual displacement spectra are established in accord with Seismic Design Code for Railway Engineering. So, it can provide the design spectra for performance-based seismic design for bridge considering residual displacement.2. Seismic energy response and its distributions of SDOF system and MDOF bridges are systematically study. And energy response spectra are established in accord with Seismic Design Code for Railway Engineering. (1) Based on nonlinear energy response analysis,320 strong motions are used to study the effect of parameters of earthquake motion and restoring model on seismic energy response and its distributions of SDOF system. (2) Nonlinear energy response analysis is carried on to research seismic energy response and its distributions of a double-column pier of passenger dedicated line considering soil-structure interaction. (3) Seismic input energy spetra and dissipation energy spectra are established in accord with Seismic Design Code for Railway Engineering. So, it can provide energy response spectra data for normalized parameters of cumulative dissipation energy and seismic checking method based on energy index.3. Performance-based seismic design for bridge considering residual displacement is proposed. And seismic checking method based on energy index is improved. (1) Based on Park-Ang seismic damage model, normalized parameters of cumulative dissipation energy are statistically calculated. So, equivalent ductility coefficients in accord with damage indexes are obtained. Furthermore, based on damage index, performance-based seismic design for bridge considering residual displacement is proposed by associating equivalent ductility coefficients with elasto-plastic displacement spetra and residual displacement spectra. Meanwhile, specific examples are provided to show the detailed design procedures. And the feasibility of proposed seismic design is confirmed by the nonlinear time history analysis. (2) According to seismic input energy spetra and dissipation energy spectra, seismic checking method based on energy index is improved and applied in the checking calculation for the seismic design result.4. To be aimed at Chinese bridges, improved simplified capacity spectrum method and vulnerability analysis considering soil-structure interaction effects are proposed. (1) Elasto-plastic demand spetra and strength reduction factor spectra are established in accord with Seismic Design Code for Railway Engineering. So, improved simplified capacity spectrum method is proposed by combining with the merits of ATC-40 and FEMA356. Meanwhile, proposed method is applied in a double-column pier of passenger dedicated line to do accuracy checking. (2) Based on the capacity spectrum method (CSM) considering soil-structure interaction (SSI) in FEMA440, one double-column pier of passenger dedicated line is chosen to be subject investigated. And the practicability of applying CSM considering SSI in bridge seismic evaluation is certified. (3) By combining CSM considering SSI in FEMA440 with vulnerability analysis, a new bridge vulnerability analysis considering flexible foundation effects, kinematic effects and foundation damping effects is proposed and applied in the vulnerability analysis of viaduct. By comparing with the vulnerability analysis without considering soil-structure interaction, the superiority of proposed method is confirmed.5. Nonlinear static procedures (NSP) considering the multiple-modes effects in ATC-40 and FEMA356 is improved. Furthermore, by combing with vulnerability analysis, the improved NSP is applying in seismic evaluation for super high-rise pier considering soil-structure interaction effects. And effect of multiple-modes effects on vulnerability analysis for super high-rise is studied.更多还原