体外预应力加固刚构桥及锚固分析

随着交通量的增加和荷载等级的不断提高,旧桥加固问题愈加突出。为研究大跨度刚构桥体外预应力加固后的结构性能以及锚固块空间应力分布情况,采用有限元程序ANSYS分别对主跨160 m连续刚构桥加固后的承载能力和边跨锚固块的空间应力进行了分析。分析结果表明,体外预应力加固能有效地提高结构的承载能力、改善结构性能,应用于大跨度连续刚构桥梁加固是有效可行的;同时指出,锚固区箱梁中的主要拉应力存在于箱梁边缘及转向孔边缘。分析结果可为同类桥梁的加固提供参考。

STUDY ON THE RIGID FRAME BRIDGE STRENGTHENED BY EXTERNAL PRESTRESSING TENDONS AND ANCHOR BLOCKS

With the increase of traffic volumn and the improvement of load grade,the issue of old bridge reinforcement becomes more prominent.In order to study the structural performance of large-span rigid frame bridges strengthened by external prestressing tendons and the spatial stress distribution of anchor blocks,the finite element program ANSYS is used to analyzed respectively the load bearing capacity of the strengthened continuous rigid frame bridge with the main span of 160 m and the spatial stresses of side-span anchor block.The results show that external prestressing can enhance the carrying capacity effectively and improve structural performance significantly,and large-span continuous rigid frame bridge strengthened by external prestressing tendons is effective and practicable;meanwhile,it is pointed out that the principal tensile stresses of the box girder at anchorage zone are existing in the box girder edge and the crossover port edge are also described.The results can provide a reference for the reinforcement of similar bridges.