多跨倾斜PC连续梁桥预拱度设置方法

Precamber Setting Method for Multi-span Inclined PC Continuous Beam Bridge

摘要:

预拱度的设置关系到车辆高速运行的舒适性和安全性。为解决大跨径桥梁悬臂施工过程中桥梁预拱度线形不达标的问题，适应桥梁实际工程特点，提出一种考虑结构自重、预应力、收缩徐变效应、汽车荷载和温度效应等多种影响因素的预拱度设置和调整方法。以南昌某多跨倾斜PC连续梁桥为背景，基于设计文件和MIDAS Civil程序，建立空间杆系结构纵向计算模型，对该桥的施工过程进行了模拟计算，得到了各节梁段的预拱度并用于指导施工。监控结果表明：大桥成桥线形高程与监控成桥高程误差符合规范要求，二者高差绝对值不超过20 mm，所提方法理论清晰、简便可行。

Abstract:

The setting of precamber is related to the comfort and safety of high-speed vehicle operation. In order to solve the problem of substandard precamber alignment in the cantilever construction process of long-span bridges and adapt to the actual engineering characteristics of bridges, a precamber setting and adjusting method considering various influencing factors such as structural self-weight, prestress, shrinkage and creep effects, vehicle loads and temperature effects is proposed. Taking a multi-span inclined PC continuous beam bridge in Nanchang as the background, and based on the design documents and MIDAS Civil program, a longitudinal calculation model of spatial truss structure is established. The construction process of the bridge is simulated and calculated to obtain the precamber of each beam segment, which guides the construction. The monitoring results show that the elevation error between the finished bridge alignment and the monitored finished bridge meets the standard requirements. The absolute value of elevation error of the both is less than 20 mm. The proposed method is clear, simple and feasible in theory.