控制大跨PC梁桥长期下挠的综合举措研究

针对目前大跨度预应力混凝土(PC)梁桥在运营后出现腹板开裂和跨中持续下挠等病害,在总结预应力混凝土梁桥下挠成因的基础上,以在建的主跨为155 m江西泰和赣江公路大桥为例,采用有限元法从恒载零挠度、加大跨中梁高和临时斜拉索辅助施工等新举措出发与传统设计进行分析比较,研究各种因素对预应力混凝土梁桥长期下挠的影响。结果表明:恒载零挠度设计,或者恒载零挠度设计和加大跨中梁高的综合设计措施对控制大跨度预应力混凝土梁桥的长期下挠更有效。

A Study on Comprehensive Measures of Long-term Deflection Control of Long Span Pre-stressed Concrete Girder Bridge

At present, the main problems of long span pre-stressed concrete box girder of continuous rigid frame bridges are excessive mid-span deflection and cracks in box girders. In order to find measures to control long-term deflection of pre-stressed concrete girder bridge, based on summarizing main causes of excessive mid span sag, taking a 155 m Taihe bridge over the Ganjiang River in Jiangxi as an example, new measures including zero deflection method, increasing depth of mid-span beam and temporary aided construction by virtue of stayed-cable and traditional design method are investigated and compared by using the methods of finite element. The results show that it is more effective for controlling long-term deflection of pre-stressed concrete girder bridge by adopting zero deflection design or comprehensive designing measure of combing zero deflection method with increasing depth of mid-span beam.