大跨PC梁式桥长期下挠控制的新方法

A New Method of Long-term Deflection Control of Long-span Prestressed Concrete Beam Bridge

针对混凝土梁式桥出现不同性质的裂缝和挠度过大的问题,通过研究无应力状态法的原理,结合连续梁一次落架与悬臂施工的力学差异,以某160m跨刚构桥为例,在施工过程以无应力状态法对施工进行控制,结果证明,无应力状态法可以有效减少跨中挠度、墩顶弯矩,对长期下挠控制是有效的,能够为解决大跨梁式桥的挠度问题提供参考。

In order to solve the problems of various cracks and big deflection that happen to concrete beam bridge, the principle of unstressed state method was studied. Combined with the mechanical difference between the construction of formwork and cantilever of the continuous beam, a rigid frame bridge with a span of 160 m was taken to carry out the deflection control with unstressed state method. The result shows that this method can effectively reduce the deflection of mid span and bending moment of the pier top, and is an effective way of long-term deflection control.