【作者】 郜新军；

【导师】 赵成刚；

【作者基本信息】 北京交通大学 ， 岩土工程， 2011， 博士

【摘要】 桥梁作为生命线工程的一个重要组成部分,其抗灾害能力尤为重要。历次地震中桥梁的大量破坏,使得桥梁的抗震问题受到广泛关注。但在近些年的大地震中,一些按照现有抗震规范设计的现代桥梁震害仍然十分突出,表明桥梁的抗震设计理论和方法还需要进一步的研究和改进。在桥梁的抗震计算中,单独考虑多点激励,地形效应,土-结构动力相互作用都不能全面的了解全桥的整体抗震性能,构建考虑包括以上诸多因素作用的整体计算模型对全桥动力响应进行分析很有必要。同时,地震作用下车桥耦合的动力响应问题常被分为地震和列车荷载作用下桥梁的动力响应问题和车-桥耦合振动问题这两个独立的方面,并在车-桥耦合振动问题中通常忽略地基下部结构对车-桥系统的影响。因此有必要对地基-桥梁-列车荷载联系起来进行统一的整体研究。本文针对这种情况,在前人研究的基础上主要完成了以下工作。1.基于粘弹性人工边界理论,结合桥梁、铁路等工程中的多振源问题,给出了多源集中粘弹性人工边界；算例表明,无论是对内源问题还是外源问题,该边界在计算多源问题时与粘弹性边界相比具有较高的精度。在外源问题的计算中,地震波输入通过在人工边界上施加等效荷载的方法来实现。多源集中粘弹性人工边界的引入,为桥梁抗震中地震动的多点输入奠定了基础。2.基于多源集中粘弹性人工边界条件下地震动的等效力输入方法,建立了二维空间内包括地基土体在内的能同时考虑地形效应、土-结构动力相互作用的桥梁整体分析计算模型,对一座5跨连续梁桥在地震P、SV波斜入射下的动力响应进行了计算分析；指出了桥梁抗震中考虑地形效应、土-结构动力相互作用及地震波入射角度的必要性,为该类桥梁抗震分析提供了依据。3.基于多源集中粘弹性人工边界条件,结合波动理论和介质的本构关系,推导了三维模型中地震P、SV波斜入射的等效力输入公式,建立了包括地基土体在内的能同时考虑地形效应、土-结构动力相互作用的三维整桥分析模型,对一座4跨连续刚构桥在地震P、SV波斜入射下的动力响应进行了计算分析；并通过改变桥梁参数对其在地震作用下的敏感性进行了分析；指出了不同桥梁参数对桥梁动力响应的影响程度还与地震波的入射角度、入射方位及波形有关,不同的地震动输入下同一桥梁参数对桥梁动力响应的影响权重不同。4.建立了包括地基在内的地基-桥梁-列车系统统一的整体模型,研究了地震作用下桥梁在列车以不同速度通过时的桥梁的动力响应,并对比分析了是否考虑土-结构动力相互作用以及是否考虑地震作用(包括地震波入射角等)对桥梁动力响应的影响。更多还原

【Abstract】 ABSTRACT:The bridge is an important component of lifeline engineering, it’s power to resist disaster is especially important. The aseismatic study of bridge structures is recognized widely after much damage in previous earthquake. Many scholars have engaged in this study and made great progresses. However, the earthquake damage of the modern bridge is very serious during the recent earthquake; it indicates that the aseismatic design theory and method of bridge used in the present are also insufficiency. Bridge overall seismic performance can not be learned comprehensively accounting for multiple excitations, terrain effects or SSI effect separately during seismic Calculation of the bridge, as a result, bridge overall dynamic analysis method accounting for above factors simultaneity is essential. Meanwhile, the dynamic analysis of coupled train-bridge system subjected to earthquakes is separated into aseismatic analysis of bridge and train-bridge coupled vibration, which is not consistent with the actual situation. It’s necessary to construct the overall foundation, bridge and train model. The main studies in this dissertation are listed as follows:1. The multi-sources scattering viscous-spring artificial boundaries is proposed based on single-source scattering viscous-spring artificial boundary, combined with multi-points scattering problem such as bridge, railway and so on. It can be used in endogenous multi-loads and multi-seismic dynamic loads cases, the multi-seismic dynamic loads input can be realized by applying equivalent loads on the artificial boundaries. The numerical calculate is carried and the results indicate the proposed method in the paper can improve the accuracy of viscous-spring artificial boundary compared with the situation of single scattering source. The introduction of the boundary conditions provides a theoretical basis for the bridge seismic wave seismic multi-input.2. Based on the viscous-spring superposition artificial boundaries theory, a finite element two-dimension model accounting for incident angle, soil-structure dynamic interaction and topographic effect is built by using the software and a seismic responses analysis of a five-span continuous bridge was carried out by method. The numerical results demonstrate that local topographic effect, physical properties of soil, SSI and seismic incidence angle play a certain role in seismic analysis of the bridge. 3. The equivalent loads of inclined sv/p wave on the artificial boundaries are proposed by combining the viscous-spring artificial boundary theory, stress-strain relation of materials and wave motion theory in three-dimensional model. A finite element three-dimension model which is involved with foundation, accounting for incident angle, incident direction, soil-structure dynamic interaction and topographic effect is built by using the software and a seismic responses analysis of a four-span rigid frame bridge was carried out by method. The parameters of bridge are varied in order to calculate the influence of different parameters. The numerical results demonstrate the influence of different parameters to bridge is relevant to incident angle, incident direction and waveform, the interaction restriction relations exist among those factors.4. A model involved into foundation, bridge and train is built based on the artificial boundary, the dynamic responses of the train-bridge system are calculated under various conditions that the train running at different speeds with SV seismic waves input. By comparing the results to those without earthquakes, various factors such as SSI, different wave incident degree and the train speeds influencing on the dynamic response of the train-bridge system are discussed.更多还原