武汉青山长江公路大桥跨刘大路节点桥异形墩设计

Design of Irregular Piers for Liuda Road Access Transition of Qingshan Changjiang River Highway Bridge in Wuhan

武汉青山长江公路大桥跨刘大路节点桥为T梁桥,常规下部构造无法满足跨越处建设条件。为解决这一难题,根据线路交叉情况及下方道路通行、拓宽需求,采用T形墩及大间距墩柱和盖梁形成的门式异形墩。在不同地段分别采用柱间距为12~16 m的四柱门式异形墩(盖梁高2.5 m、墩高15.3~21.5 m)、三柱门式异形墩(盖梁高2.8 m、墩高16.5~21.3 m)、双柱门式异形墩(盖梁高3.0 m、墩高14.3~21.8 m),以及双柱T形墩(盖梁高2.5 m、墩高14.0~20.2 m)。根据桥梁重载交通的需求,墩柱采用2.0 m×2.0 m或2.3 m×2.3 m方柱墩,盖梁配置13束型号为15-19的低松弛高强度预应力钢绞线,并对普通钢筋进行加密处理。经验算,异形墩结构受力满足规范要求。

The Liuda Road Access Transition of Qingshan Changjiang River Highway Bridge in Wuhan is a T beam bridge.Traditional configurations of substructure could not meet the spanning requirements of the construction site.To address this problem,the T piers and irregular portal piers with big column intervals and cap beams are designed,taking into account the convergence of different routes,the traffic below the access transition and the expansion requirements.Different piers are used in different sections,including the four-column irregular portal piers(measuring 15.3-21.5 m high,with 2.5 m-deep cap beam)spaced at 12-16 m,irregular portal piers with three columns(measuring 16.5-21.3 m high,with 2.8 m-deep cap beam),irregular portal piers with two columns(measuring 14.3-21.8 m high,with 3.0 m-deep cap beam),and two-column T piers(measuring 14.0-20.2 m high,with 2.5 m-deep cap beam).To accommodate the heavy traffic loads on the bridge,the pier columns are designed as the columns of rectangular cross section,measuring either 2.0 m×2.0 m or 2.3 m×2.3 m.The cap beams are strengthened by 13,15-19 low-relaxation and high-strength prestressing tendons,and extra reinforced bars are added to the locations with common reinforcement.The results of checking calculation show that the load bearing capacity of the irregular piers can meet the code requirements.