斜陡横坡桥梁桩柱式下部结构设计关键点分析

Analysis on Key Points in Design of Pile-column Substructure of Bridges on Steep Cross Slopes

摘要:

山区桥梁下部结构设计往往面临着陡坡、斜坡、倾斜岩面较多，横桥向桥墩高差较大等难点，为避免承台的大挖方，桩柱式下部结构成了很多山区桥梁下部结构的首选。南充市南海大道桥梁是一座典型的山区斜陡横坡条件下的桥梁，下部结构采用盖梁桩柱式框架结构。为了研究斜陡横坡对该桥下部结构设计的影响，通过工程经验结合理论分析研究了斜坡地形与倾斜岩面对桥梁桩基承载力计算、桩长及嵌岩深度的影响，通过有限元计算分析研究了斜陡横坡引起的横桥向高低墩对盖梁、墩柱内力分配的影响。最终通过设置桩基承载力起算点、桩基嵌岩深度起算点及合理配筋等方式，妥善解决了斜陡横坡对该桥下部结构设计的影响，可为同类山区桥梁下部结构设计提供有效参考。

Abstract:

The design of bridge substructures in mountainous areas often encounters difficulties such as a large number of steep slopes, ramps and inclined rock faces, as well as a significant height difference between the piers in the transverse direction. To avoid the extensive excavation of base slabs, the pile-column substructure has become the preferred choice for many bridges in mountainous areas. The Nanhai Avenue Bridge in Nanchong City is a typical bridge under steep cross slope conditions, and its substructure is a bent-cap pile-column frame structure. To study the impact of steep cross slopes on the substructure design of this bridge, the influence of sloped terrain and inclined rock surfaces on the calculation of pile foundation bearing capacity, pile length, and rock-socketed depth is studied through engineering experience combined with theoretical analysis. The effect of transverse height differences between piers caused by steep cross slopes on the internal force distribution of bent caps and piers is analyzed using finite element computational methods. Finally, through setting the starting point for the bearing capacity of the pile foundation, the starting point for the rock-socketed depth of pile foundation, and the reasonable reinforcement, the influence of the steep cross slope on the substructure design of the bridge has been properly addressed, which provides a valuable reference for the substructure design of similar mountainous bridges.