大跨高低墩连续刚构桥合龙顶推力计算分析

Calculation and Analysis of Closure Jacking Force of Continuous Rigid Frame Bridgewith Long-span High-low Pier

合龙顶推施工是建造连续刚构桥施工过程中的关键工序,以跨越一不对称狭长山谷的连续刚构桥(65m+120m+65m)为依托,分析了桥墩墩顶位移、控制截面内力和应力改善情况,提出了大跨高低墩连续刚构桥合龙顶推力的计算方法。计算方法考虑了恒荷载产生的有利影响,以及预应力效应、高温合龙、收缩徐变产生的不利影响。大跨高低墩连续刚构桥的主墩刚度差异较大,各主墩最有利顶推力值相差也较大,可以取其平均值作为设计顶推力。

The closure jacking construction is a key process during the construction of continuous rigid frame bridge.Based on the continuous rigid frame bridge(65m+120m+65m)crossing an asymmetric narrow valley,the improvement of pier top displacement,internal force and stress of control section is analyzed,and the calculation method of closure jacking force of continuous rigid frame bridge with long-span high-low pier is put forward.The favorable effects of dead load and the adverse effects of prestress effect,high-temperature closure,shrinkage and creep are considered in the calculation method.The main pier stiffness of continuous rigid frame bridge with long-span high-low pier varies greatly,and the most favorable jacking force value of each main pier also varies greatly,and its average value can be taken as the designed jacking force.