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在迅速崛起的西部高原山区高墩大跨桥梁多以百米左右的高墩大跨连续刚构桥为主,其几何非线性问题变得越来越重要。为了研究桩土作用下该结构的几何非线性效应,以西部某高墩大跨连续刚构桥为依托工程,利用大型有限元软件进行了考虑桩土效应的几何非线性施工全过程模拟。对比分析了该类型桥梁在桩土作用下几何非线性效应对结构应力和位移在施工阶段及成桥后的影响程度,并研究了不同墩高情况下几何非线性效应对该类型桥梁的变形及结构内力的影响规律。分析结果表明:几何非线性效应对主梁断面顶、底板应力的影响随着悬臂长度的增加而逐渐增大;考虑比不考虑几何非线性效应的主梁竖向位移值小,且位移曲线平顺连续;几何非线性效应对主梁弯矩和主墩剪力影响较大,且剪力分布的非线性随墩身高度的增加而明显,呈先增大后减小的现象;几何非线性效应对边跨主梁弯矩的影响效应随墩高的增加而减小,对墩顶及中跨主梁弯矩的影响随墩高的增加而增大。为了更好地控制结构应力及线形,建议高墩大跨连续结构在设计及施工控制中应着重计入几何非线性效应的影响。
In the rapid rise of western plateau mountainous area, high-span long-span bridges are mostly dominated by high-pier long-span continuous rigid frame bridges with a height of about 100 meters, and their geometric nonlinearity problems become more and more important. In order to study the geometric nonlinear effect of the structure under the action of pile and soil, a large-span continuous rigid frame bridge with a high pier in the west is relied on the project. The whole process simulation of geometric nonlinear construction considering pile-soil effect is carried out by using the large-scale finite element software. The effect of geometrical nonlinearity on the stress and displacement of the bridge under the action of pile and soil is compared and analyzed in the construction phase and after the completion of the bridge. The effects of geometric nonlinearity on the deformation of the bridge and the deformation of the bridge are studied. Influence of structure internal forces. The results show that the influence of geometrical nonlinear effect on the stress of roof and floor of the main girder section increases with the increase of cantilever length. Considering that the vertical displacement of main girder, which does not consider the geometric nonlinear effect, is small and the displacement curve is smooth The geometric nonlinear effect has a great influence on the bending moment of the main girder and the main pier shear force, and the nonlinearity of the shear distribution is obvious with the increase of pier height, which increases first and then decreases. The geometric nonlinear effect The effect of the bending moment of the side-to-side main beam decreases with the increase of the pier height, and the influence on the bending moment of the pier girder and mid-span girder increases with the increase of pier height. In order to better control the structural stress and linearity, it is suggested that the influence of geometric nonlinearity should be included in the design and construction control of high-pier and long-span continuous structures.