HDR隔震支座梁桥横向碰撞参数分析

发布时间：2018-08-15 16:28

【摘要】：我国中小跨径的梁桥,较多采用的是普通板式橡胶支座,但板式橡胶支座在地震作用下容易出现滑动或脱空现象,造成梁体很大的侧向位移,此时支座的传力功能通常会丧失。为了限制梁体的横向位移,混凝土挡块被普遍采用,混凝土挡块设计的目的是限制梁体的横向位移,但同时也会增大梁体与挡块碰撞的概率,并且混凝土挡块受到的横向碰撞会通过盖梁出现一系列传力作用,造成墩柱更加不利的受力。在我国的公路桥梁抗震规范中,混凝土挡块仅作为一种构造措施,在与梁体发生碰撞时,挡块往往发生破坏,因此防止横向落梁的作用就被大大削弱。针对板式支座梁桥横向碰撞效应的震害,本文以一座4跨简支变连续小箱梁为工程背景,利用ANSYS有限元计算软件,通过建立普通板式支座桥梁、HDR隔震支座桥梁,对比考虑碰撞与不考虑碰撞效应下结构响应的差异,并对HDR隔震支座梁桥横向碰撞效应参数进行研究,主要对模拟梁体与挡块之间碰撞效应的接触单元碰撞刚度、接触单元初始间隙、上下部结构质量比、墩高、墩柱弹塑性等参数进行分析,得出相对于普通板式支座,HDR隔震支座可以很好的减弱梁体碰撞效应。通过减小接触单元碰撞刚度也可以减小横向碰撞效应,但会造成墩梁相对位移的增大,对于HDR隔震支座梁桥,增大初始间隙可以减弱横向碰撞效应,上下部质量比对结构的横向碰撞效应成正相关的关系,墩高在一定范围内变化时,对结构横向碰撞效应影响较大,不考虑墩柱弹塑性,会得出下部结构保守的计算结果。通过在盖梁与梁体间安装剪切耗能板,对比HDR隔震支座、板式支座分别配合剪切耗能板时结构的横向地震响应,得出HDR支座配合剪切耗能板在不显著增大下部结构的内力情况下,可以很好的控制墩梁相对位移;通过改变剪切耗能板的屈服强度,可以控制梁体与混凝土挡块碰撞效应,当剪切耗能板屈服位移为0.02m时,屈服强度的取值建议过渡墩取上部恒载的0.2倍,中墩取上部恒载的0.3倍。
[Abstract]:In the middle and small span beam bridges in our country, the common plate rubber bearings are more often used, but the plate rubber bearings are prone to slip or empty under the earthquake, which results in a large lateral displacement of the beam body. At this time, the force transfer function of the support will usually be lost. In order to limit the transverse displacement of the beam, the concrete block is widely used. The purpose of the concrete block design is to limit the transverse displacement of the beam, but at the same time, it will increase the probability of collision between the beam and the block. And the transverse impact of the concrete block will cause a series of force transfer through the cover beam, resulting in more unfavorable force on the pier column. In the seismic code of highway bridges in our country, concrete block is only a kind of structural measure, when it collides with beam body, the block is often destroyed, so the function of preventing transverse falling beam is greatly weakened. In view of the earthquake damage caused by the transverse collision effect of plate supported girder bridge, this paper takes a 4-span simple support variable continuous small box girder as the engineering background, using ANSYS finite element calculation software, through the establishment of the ordinary plate bearing bridge and HDR-isolation bearing bridge. Considering the difference between the structural response and the impact effect, the transverse impact parameters of the HDR isolation beam bridge are studied. The impact stiffness of the contact element is studied to simulate the impact effect between the beam body and the block. The initial clearance of the contact unit, the mass ratio of the upper and lower parts of the structure, the height of the pier and the elastoplastic properties of the pier are analyzed. It is concluded that the beam collision effect can be well weakened compared with the HDR isolation bearing of the ordinary plate bearing. The transverse impact effect can also be reduced by reducing the impact stiffness of the contact element, but will result in the increase of the relative displacement of the pier beam. For the HDR isolation support beam bridge, the transverse impact effect can be weakened by increasing the initial clearance. The upper and lower mass ratio has a positive correlation with the transverse impact effect of the structure. When the height of the pier changes within a certain range, it has a great influence on the transverse impact effect of the structure, and the calculation results of the substructure can be obtained conservatively without considering the elastoplasticity of the pier column. By installing shear energy dissipation plate between the cover beam and the beam body, the transverse seismic response of the structure is compared when the HDR isolation support and the plate bearing are respectively combined with the shear energy dissipation plate. It is concluded that the relative displacement of pier beam can be well controlled by HDR bearing combined with shear energy dissipation plate, and the collision effect between beam and concrete block can be controlled by changing the yield strength of shear energy dissipation plate. When the yield displacement of shear energy dissipation plate is 0.02m, it is suggested that the transition pier should take 0.2 times of the upper dead load and the middle pier 0.3 times of the upper dead load.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U442.55

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