【摘要】 根据谐波合成法,利用Fortran编制了基于功率谱输入的多点人工波生成程序。以目前跨度最大的双层公路斜拉桥——上海闵浦大桥为研究对象,研究大跨双层斜拉桥的多点激励地震响应。基于Abaqus平台建立了该桥精细梁壳有限元模型。在静力几何非线性分析的基础上进行特征值分析与几何非线性多点激励时程分析,给出了全桥的动力特性与主塔、辅助墩的主要地震内力以及桥面间腹杆(竖腹杆、斜腹杆、边斜杆)轴力变化规律。研究表明:辅助墩横梁以下墩身横桥向剪力分布均匀,且距主塔越远其墩身横桥向剪力和弯矩越大。边跨上、下层桥面间的腹杆轴力变化较大,尤其是墩顶附近的竖腹杆和斜腹杆。边斜杆轴力分布较为均匀,但位于墩顶与跨中断面处的边斜杆轴力较小。跨中处竖腹杆和斜腹杆轴力较小,中跨其他腹杆轴力较均匀。更多还原

【Abstract】 A multi-support motion generation program was developed in Fortran based on the power spectrum input according to harmonic composition method.Shanghai Minpu Bridge,which is the longest double-deck long-span highway cable-stayed bridge,was taken as example to study the seismic response of the bridge under multi-support excitations.A fine finite element model with beams and shells was built on the basis of platform Abaqus.The eigenvalue analysis and the time history analysis under nonlinear multi-support excitations were performed based on the geometrical nonlinear static analysis to get the dynamic characteristics as well as the variations of the internal forces in the main towers and the subsidiary piers and the axial forces of the web members(vertical,oblique and squint web members).The results show that the lateral shear force in the pier column below the subsidiary pier beam distribute uniformly.It increases with the distance from the main tower,so does the lateral moment.The axial forces of the web members of side span between upper and lower decks vary significantly,especially the vertical and oblique members near the pier top.The axial forces in the squint web members are well distributed and those at the pier top and at the mid-span are relatively small.The axial forces in the vertical and oblique web members at mid-span are small,and those in the other web members vary little.更多还原