半山桥下部结构组合体系抗倾覆稳定性设计

Mid Mountain Bridge Substructure Composite System Anti-Overturning Stability Design

山区道路拓宽工程采用半山桥结构型式,经常面临高墩、盖梁大悬臂等问题,成为下部结构设计过程的一大难题。结合龙泉市凤阳山区通景公路改建工程的桥梁设计,对半山桥盖梁与立柱组合体系的力学性能进行分析。考虑桩周土和基岩上部填土对桩基的影响,计算独柱式与双柱式桥墩发生侧向倾覆时的临界盖梁悬臂长度,得到2种桥墩不同跨数与不同盖梁总长的桩基嵌岩深度设计值。结果表明:盖梁的几何形态是决定嵌岩桩嵌入岩层深度的关键因素,盖梁外悬臂长度的改变将直接导致嵌岩深度显著变化。

Mountainous road expansion project often adopt mid mountain bridge structure,which often encounter with high pier and bent cap large cantilever,etc.,this could be a big problem for substructure design.Based on bridge design in mountainous Tongjing road reconstruct project in Fengyang,Longquan City,this paper made analysis to mechanical performance of bent cap and pile composite system of mid mountain bridge.Considering influence to pile foundation by surrounding soil and backfill on top of bed rock,the interim bent cap cantilever length at lateral overturning on single pile and double pile pier,so to get the designed value of rock socket depth of pile foundation of these two piers at different laps and different bent cap total lengths.Result shows： The geometric form of bent cap is the key factor deciding rock socket pile depth,the change of bent cap cantilever length will directly influence the rock socket depth.