斜交连续梁桥地震位移响应及典型参数规律研究

Seismic displacement response and influence of typical parameters on continuous skewed bridges

为了揭示斜交连续梁桥的地震破坏规律,提高这类桥梁抗震设计的针对性,选取汶川震害中某典型斜交连续梁桥为原型,以支座摩擦系数、斜交角、主梁跨数、墩高为参数构建了15个分析桥例。考虑支座滑移、挡块退化、桥台伸缩缝碰撞等非线性因素,基于OpenSEES开源程序建立模型,采用非线性时程分析方法研究了斜交连续梁桥地震位移响应特点及其参数影响规律。研究表明:由于支座滑移且缺乏自复位能力,斜交连续梁桥的典型地震响应为主梁的双向耦合位移和平面旋转;梁端纵、横向残余位移均随着斜交角的增大而先增后减,主梁平面转角则先增后减,最大平面转角出现在斜交角为45°时;连续跨数增多会导致梁端纵、横向位移先减后增,单跨的平面转角是4跨的11.1倍;随着墩高的增加,梁端纵、横向位移不断增大,主梁平面转角呈先减后增的变化规律,墩高为16m时出现最小值。

In order to reveal the earthquake damage law of the continuous skewed girder bridge and improve the pertinence of the seismic design of this type of bridge,a typical continuous skewed girder bridge in the Wenchuan earthquake is selected as the prototype,and 15 analytical bridge examples are constructed with the parameters of support friction coefficient,skew angle,main girder span,and pier height.Considering the non-linear factors such as support slip,block degradation,and abutment expansion joint collision,the model is established based on the OpenSEES open source program,and the nonlinear time history analysis method is used to study the seismic displacement response characteristics of the continuous skewed girder bridge and the influence of its parameters.The research shows that due to the sliding of the support and the lack of self-reset capability,the typical seismic response of the continuous skewed girder bridge is the bidirectional coupling displacement and plane rotation of the main beam;the longitudinal and lateral residual displacements of the beam end first increase and then decrease with the increase of the skew angle,and the plane rotation angle of the main beam first increases and then decreases,the maximum plane rotation angle appears when the skew angle is 45°;the increase in the number of continuous spans will cause the longitudinal and lateral displacement of the beam end to decrease first and then increase,the plane angle of a single span is 11.1 of 4 spans;with the height of the pier increases,the longitudinal and lateral displacements of the beam ends continue to increase,and the plane rotation angle of the main beam first decreases and then increases,the minimum value appears when the pier height is 16m.