高墩大跨连续刚构桥合龙方案选择与顶推控制研究

Closure Scheme and Jacking Control of Long-span Continuous Rigid Frame Bridge with High Piers

多跨连续刚构桥合龙段的数量多,施工过程复杂。为了得到青海省某黄河特大桥的最优合龙顺序,基于不同的合龙方案,采用Midas-Civil分别建立各方案不加顶推时的分析模型,借用数值分析模型的非线性计算能力和有限元软件的后期处理功能,得到了各墩顶在成桥十年后产生的水平位移量。以完全消除此水平位移量为目标,计算各合龙方案所需水平顶推力的理论值。通过比较顶推前后墩顶的水平变位及主梁和桥墩关键部位的内力,确定出在"先边、中跨再次中跨"的合龙方案下可以得到一个较为合理的成桥状态,而且施工过程容易控制,作业效率高。

Multi-span continuous rigid frame bridges have many closing segments and its construction is complex. In order to obtain the best closure sequence of the large bridge along the Yellow River in Qinghai province,this paper studies on different closure scheme,using Midas-Civil to establish the analysis models which are not pushed when closing. Benefit from the nonlinear calculation ability of the numerical analysis model and the post-processing function of the finite element software,we get the horizontal displacements of the pier top 10 years later. Then,aiming at completely eliminating the above displacements,we calculate the theoretical value of the horizontal jacking force required for each closure scheme. Finally,by comparing the horizontal displacement of the pier top before or after closing as well as the internal force of the key parts of the main girder and pier,we conclude that a more reasonable bridge condition can be obtained under the ＂Side-edge,mid-span and mid-span＂closure strategy,and the construction is easy to control,with high operating efficiency.