【作者】 王勇；

【导师】 周凌远；

【作者基本信息】 西南交通大学 ， 建筑与土木工程， 2015， 硕士

【摘要】 近断层地震竖向与水平向加速度峰值比通常是取为1/2-2/3。而近年来的研究发现,这一比值和震级、震中距、周期等因素的关系非常密切,竖向与水平向加速度谱比值的曲线在短周期段的峰值随断层距的减小而增大,很多近断层地震动记录的竖向与水平向加速度峰值比超过2/3。部分竖向峰值加速度竟然超过了水平向峰值加速度,因此这一比值取值明显偏小。在铁路桥梁的抗震设计中,小于9度地震竖向地震动的影响一般是不考虑的,但随着对强震中结构破坏现象的调查和研究,以及越来越多的地震记录显示,特别是近断层区域及震中区域,竖向地震动的作用相当显著,造成了许多结构的破坏。因此,研究竖向地震动的规律特点及对连续梁桥的影响显得尤为重要。论文以四座跨径不同的铁路连续梁桥为研究对象,建立四组有限元模型,研究竖向地震动对桥梁结构的影响,研究内容主要包括以下内容：(1).通过对大量地震动数据的处理,具体阐述了近断层竖向地震动加速度峰值比和PGV/PG4与震级、断层距、断层类型和剪切波速的关系。(2).通过有限元软件MIDAS建立四组连续梁模型,输入不同峰值的竖向加速度,研究竖向地震动作用下连续梁桥上部结构的反应；通过输入同等峰值的竖向加速度,研究竖向地震动对不同跨径连续梁桥的影响及规律。(3).研究了竖向地震动对不同高度桥墩的影响及规律特点,分析了不同高度桥墩在竖向地震动作用下可能发生的破坏形式。更多还原

【Abstract】 The peak acceleration ratio of vertical and horizontal of near-fault earthquakes is usually taken as 1/2-2/3. In recent years, researchs on ground motion show that this ratio is closely related to the magnitude, epicenter distance, and other factors. And some vertical peak acceleration is even greater than the horizontal peak acceleration, therefore, the taken ratio is maybe smaller than actural one. In general the seismic design and analysis, In seismic design of railway bridge, the influence of less than 9 degree earthquake is not considered. But with the investigation and research of earthquake damage phenomenon, and more and more seismic records show that, especially near-fault region and the epicenter of the region, the influence of the vertical ground motion is significant, resulting in the destruction of many of the structural. So, Characteristics of vertical ground motion and the effect on continuous girder bridge is particularly important and should be studied further.Four different span railway continuous beam bridge is analysised as the research objects. The structures are modled using finite element method to study the reaction of the bridge structure under vertical earthquake. The main contents of the research are as follows:(1). Through the processing of the massive seismic data, the relationship between the peak ratio of the vertical earthquake acceleration and the PGV/PGA and the relationship of the magnitude, the fault distance, the fault type and the shear wave velocity of the near fault is studied.(2).Based on the four groups of continuous beam model established by finite element software MIDAS, different vertical acceleration peak values are inputted to study on vertical seismic response of the continuous beam bridge superstructure; And the rule of the vertical seismic effect on different span continuous beam bridge is also revealed through analysis the reaction of structures under the same peak vertical acceleration.(3).The reactions of piers with different height under vertical ground motion are calculated, and relation between failure types and height of piers under vertical earthquake are revealed.更多还原