预应力混凝土连续梁桥顶推施工中落梁方案比选

Selection of scheme of jacking-down of girder in incremental launching construction of prestressed concrete continuous girder bridge

以振东路三跨预应力混凝土连续箱梁桥为研究对象,通过在支承节点处施加竖向强迫位移的方式来模拟主梁的落梁,分析了单墩、双墩和三墩起顶时该桥的结构受力状态,计算了各起顶方案的千斤顶顶升力和主梁的应力。综合考虑施工条件,最终选择单墩起顶的落梁方案,同时将理论值与实测结果进行比较。结果表明:落梁过程中采用单墩、双墩和三墩起顶的落梁方案各墩的千斤顶顶升力相差不大、梁体应力满足要求。采用单墩起顶时箱梁顶、底板始终处于受压状态,顶升力和箱梁应力的有限元的计算结果与实测结果吻合较好。

Taking the three-span prestressed concrete continuous box girder bridge of Zhendong Road as the research object,the process of jacking-down of the concrete box girder of the bridge was simulated and analyzed by method of applying forced vertical displacement at the support nodal point,analyzed the structural stress state of the bridge,the jacking forces of the jacks and the stress of the girder were calculated when the single pier,double pier and three pier are raised.Considering the construction conditions comprehensively,the project of single pier is finally selected,and the theoretical value is compared with the measured result.The results show that the stress of the girder of the project with single pier,two piers and three piers is satisfied.The top and bottom slabs of the box girder with songle pier are always under compression,the simulation calculations of jacking forces and the stress of the girder are agree well with the measurements.