钢-混凝土结合桁架拱桥施工控制技术

Construction Control Technology of Steel-Concrete Combined Truss Arch Bridge

为了使钢-混凝土结合桁架拱桥成桥后达到合理的内力和线形状态,以成都—贵阳铁路鸭池河特大桥为例介绍了大桥施工全过程控制技术。拱肋钢桁架拼装阶段,重点控制预拼场内胎架上拱肋节段组拼线形和桥位处拱肋节段悬臂拼装线形;拱肋混凝土浇筑阶段,根据模拟分析结果优化拱肋施工过程中的受力,并对关键受力部位进行重点监测;主梁大节段浇筑阶段,对主梁进行一次性总体预拱度设置,对吊杆索力分两阶段张拉控制。成桥后经现场实测,拱肋、主梁高程偏差总体上在50 mm以内,吊杆索力偏差总体上在5%以内,其偏差均在合理范围内,满足规范要求。

In order to make the steel-concrete combined truss arch bridge reach a reasonable internal force and alignment state after completion,the whole process construction control technology of the bridge was introduced based on Yachihe bridge on Chengdu-Guiyang railway.In the assembly stage of arch rib steel truss,the assembly alignment of arch rib segments on the inner tube frame in the pre-assembly yard and the cantilever assembly alignment of arch rib segments at the bridge site shall be mainly controlled.In the concrete pouring stage of arch rib,the stress in the construction process of arch rib was optimized according to the simulation analysis results,and the key stress parts were monitored.In the pouring stage of large segments of the main girder,the overall camber of the main girder shall be set at one time,and the cable force of the suspender shall be tensioned and controlled in two stages.After the completion of the bridge,according to the field measurement,the elevation deviation of arch rib and main girder is generally within50 mm,and the cable force deviation of suspender is generally within 5%.The deviation is within a reasonable range and meets the specification requirements.