山区高速公路桥梁圆柱式墩抗震设计

Seismic Design of Cylindrical Piers of Mountain Expressway Bridges

山区高速公路的突出特点是地形条件复杂、桥隧比高、施工条件差。根据墩高不同,桥墩一般采用圆柱式墩、方墩、箱型墩等设计方案。方墩、箱型墩需要设置群桩基础,基础尺寸较大,其需要开挖较大的施工平台,对山体的破坏比较严重。为贯彻"绿色公路"设计理念,桥墩应尽可能避免设置群桩基础,采用圆柱式墩。本文利用Midas有限元软件,建立了35 m墩高圆柱式桥墩有限元分析模型,验算在Ⅶ度区地震作用下桥墩的抗震性能。结果表明,圆柱式墩满足抗震要求,这就为山区高速公路项目圆柱式墩设计提供了参考。

The outstanding features of mountain expressways are complex terrain conditions,high bridge-tunnel ratios,and poor construction conditions.According to different pier heights,the piers generally adopt cylindrical piers,square piers,box piers and other design schemes.Square piers and box-shaped piers need to be equipped with group pile foundations,and the foundation size is larger,which requires a larger construction platform to be excavated,and the damage to the mountain is more serious.In order to implement the"green highway"design concept,the piers should avoid setting pile foundations as much as possible and adopt cylindrical piers.In this paper,by using Midas finite element software,a finite element analysis model of a 35 m pier height cylindrical pier was established,and the seismic performance of the pier under the action of an earthquake in theⅦdegree area was checked.The results show that the cylindrical pier meets the seismic requirements,which provides a reference for the design of the cylindrical pier in mountainous expressway projects.