【作者】 傅平；

【导师】 郑玉芳； 李梁峰；

【作者基本信息】 福州大学 ， 建筑与土木工程（专业学位）， 2020， 硕士

【摘要】 连续刚构桥中主梁与桥墩的连接形式一般为正交,其地震作用下桥梁的地震响应分析已较为成熟。受地形地貌和桥位的限制,部分刚构桥的主梁与桥墩成斜交角布置,其地震作用下的桥梁地震反应较为复杂,目前规范中对于此类非规则桥的抗震并没有给出具体的建议。本文以一座主梁与桥墩有10°斜交角的刚构桥为研究对象,对地震作用下的斜交刚构桥进行易损性分析和震后桥梁通行能力分析。本文主要研究内容如下:(1)利用ANSYS软件建立斜交角为0°、10°、30°、45°的刚构桥模型。选用Chichi波、Kobe波以及Loma Prieta波,分析单向地震波和双向地震波对斜交刚构桥内力和位移的影响。结果表明,同一桥梁模型,双向地震波下的墩底弯矩(My)和扭矩比单向地震波至少提高27.9%和2倍,说明双向地震波下桥梁的弯扭耦合现象更为严重。(2)采用OpenSees软件建立四种斜交刚构桥模型,选择22条地震波,采用增量动力分析方法(IDA)进行易损性分析。选择截面曲率作为桥墩的损伤指标,支座位移作为支座的损伤指标,并将损伤指标量化,得到在单向地震和双向地震作用下,桥墩、支座以及全桥的易损性曲线。在此基础上,分析斜交角以及地震波输入方式对桥梁易损性的影响。结果表明,同一桥梁在相同地震动强度下,双向地震作用下的损伤超越概率大于横桥向地震动;同时斜度越大,越容易损伤。(3)为了解主桥与桥台碰撞的影响,建立考虑碰撞的四种斜交刚构桥模型。研究碰撞对斜交刚构桥在地震作用下桥梁易损性的影响,分析考虑碰撞工况下桥墩、支座以及全桥易损性曲线。结果表明,碰撞将导致地震作用下桥墩最大曲率的降低,使桥墩的损伤超越概率变小;同时,碰撞会降低斜交角对支座易损性曲线的影响,导致同一地震动强度作用下,不同斜交桥梁的支座损伤超越概率相差不大;但主梁与桥台间的碰撞力对结构是不利的。(4)研究双向地震作用下斜交刚构桥的震后通行能力。在双向地震作用下,基于一阶界限法得到的全桥易损性曲线,评估四种桥梁模型在碰撞前后桥梁的快速通行能力、可通行交通流量以及车辆行驶时间。研究表明,斜交刚构桥的斜度越大,通车时间越长,对救灾越不利。本论文研究可为斜交刚构桥工程的防震减灾工作提供一定的参考。更多还原

【Abstract】 The connection form of the main beam and the pier in a continuous rigid frame bridge is generally orthogonal,and the seismic response analysis of the bridge under its earthquake action is relatively mature.Restricted by topography and bridge position,the main beams of some rigid frame bridges are arranged at an oblique angle to the pier,and the seismic response of the bridge under the action of earthquake is relatively complicated.The current seismic code for such irregular bridges does not give suggestions in detail.In this paper,a rigid frame bridge with a main beam and a pier with a skew angle of 10° is taken as the research object.The vulnerability analysis and the traffic capacity analysis of the skew rigid frame bridge under earthquake action are carried out.The main research contents of this article are as follows:(1)Use ANSYS software to establish rigid-frame bridge models with skew angles of 0°,10°,30°,and 45°.Chichi waves,Kobe waves and Loma Prieta waves were selected to analyze the effects of unidirectional seismic waves and bidirectional seismic waves on the internal forces and displacements of the skew rigid frame bridge.The results show that with the same bridge model,the bending moment(My)and torque at the bottom of the pier under the two-way seismic wave are at least 27.9%and 2 times higher than those of the one-way seismic wave,indicating that the bending-torsion coupling phenomenon of the bridge under the two-way seismic wave is more serious.(2)Open Sees software was used to establish four types of skew rigid frame bridge models,and 22 seismic waves were used for incremental vulnerability analysis(IDA)for vulnerability analysis.Select the curvature of the cross section as the damage index of the pier,and the displacement of the support as the damage index of the support,and quantify the damage index to obtain the vulnerability curves of the pier,the support and the entire bridge under the action of one-way earthquake and two-way earthquake.On this basis,the influence of the skew angle and the seismic wave input method on the vulnerability of the bridge is analyzed.The results show that under the same ground motion intensity,the probability of damage surpassing under the action of two-way earthquakes is greater than that of transverse bridges;at the same time,the greater the slope,the easier the damage.(3)In order to understand the impact of the collision between the main bridge and the abutment,four models of skew rigid frame bridges considering collision are established.The impact of collision on the vulnerability of the skew rigid frame bridge under earthquake is studied,and the vulnerability curves of the piers,supports and the full bridge under collision conditions are analyzed.The results show that the collision will reduce the maximum curvature of the bridge piers under the action of earthquake,and make the damage probability of the bridge piers become smaller.At the same time,the collision will reduce the impact of the skew angle on the bearing’s vulnerability curve,resulting in a small difference in the probability of surpassing the damage to the bearing of different skew bridges under the same ground motion intensity.However,the collision force between the main beam and the abutment is detrimental to the structure.(4)Study the post-earthquake capacity of the skew rigid frame bridge under the bidirectional earthquake.Under the action of two-way earthquakes,based on the full-bridge fragility curve obtained by the first-order limit method,the rapid capacity,traffic flow,and vehicle travel time of the four bridge models before and after the collision were evaluated.Studies have shown that the greater the slope of the skew rigid frame bridge,the longer the opening time and the more disadvantageous it is for disaster relief.The research in this paper can provide a certain reference for the earthquake prevention and disaster reduction work of the skew rigid frame bridge project.更多还原