高烈度山区场地非线性效应对连续刚构桥地震响应的影响分析

发布时间：2018-09-08 20:04

【摘要】：为了研究高烈度山区地震场地非线性效应及其对连续刚构桥地震响应的影响,选取具有代表性的20条地震波,基于土层分析软件Deepsoil和通用有限元软件ANSYS,计算分析等效线性和非线性两种模型的场地效应和桥梁结构地震响应。结果表明:(1)考虑非线性模型时地表PGA放大系数比等效线性模型时更大,且土层越柔软,非线性模型下的地表PGA放大系数越大。小震、大震作用下的放大系数依次为1.5~3.5、1.3~1.7,呈减小趋势。(2)随着地震动强度增大,两种模型得出的土层峰值加速度随土层深度变化趋势逐渐出现差异,且非线性整体大于等效线性。在大震作用下,非线性约为等效线性的1.36倍;在软弱土层处更明显,约为1.54倍。(3)小震作用下,两种模型计算得出的地表加速度反应谱接近,呈现一致的变化规律。大震作用下,非线性模型得出的反应谱起伏变宽,峰值变大。(4)非线性得出的桥墩底剪力和弯矩均方根值约为等效线性的1.37倍,因此采用非线性模型考虑场地效应对结构响应影响较大。
[Abstract]:In order to study the nonlinear effect of seismic site and its influence on seismic response of continuous rigid frame bridge in high intensity mountain area, 20 representative seismic waves were selected. Based on the soil layer analysis software Deepsoil and the general finite element software ANSYS, the site effect and the seismic response of the bridge structure are calculated and analyzed by the equivalent linear and nonlinear models. The results show that: (1) when nonlinear model is considered, the surface PGA magnification factor is larger than that of the equivalent linear model, and the softer the soil layer, the larger the surface PGA magnification factor under the nonlinear model. The magnification factor of small earthquake and large earthquake is 1.5 ~ 3.5 ~ 1.3 ~ 1.7, which shows a decreasing trend. (2) with the increase of ground motion intensity, the peak acceleration of soil layer gradually varies with the depth of soil layer, and the nonlinearity is larger than that of equivalent linearity. Under the action of large earthquakes, the nonlinearity is about 1.36 times of equivalent linearity, and that in weak soil is more obvious, about 1.54 times. (3) under the action of small earthquakes, the ground acceleration response spectra calculated by the two models are close to each other, showing a consistent variation rule. Under the action of strong earthquake, the response spectrum of nonlinear model becomes wider and the peak value becomes larger. (4) the root mean square value of shear force and bending moment at the bottom of pier is 1.37 times that of equivalent linearity. Therefore, considering the site effect, the nonlinear model has a great influence on the structure response.
【作者单位】：西南交通大学土木工程学院;
【基金】：国家自然科学基金项目(51378443) 中国铁路总公司科技研究开发项目(2015G002-A)
【分类号】：U442.55;U448.23

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