高速铁路混凝土梁式桥预拱度设置的探讨

Discussion on Setting of Camber for Concrete Girder Bridge of High Speed Railway

高速铁路混凝土梁式桥体量较大,荷载效应中活载所占比例较恒载小。设置恒载预拱度是工程界的共识,但是否需要设置活载预拱度还存在分歧。实际高速铁路混凝土梁式桥设计中,设置活载预拱度与不设置活载预拱度的情况都存在。无论梁体是否设置活载预拱度,高速铁路混凝土梁式桥上的轨道结构均是按照线路设计纵断面的标高进行铺设的,轨面并未平行于梁面设置活载预拱度,背离了桥梁预拱度设置的初衷。基于此,本文对高速铁路混凝土梁式桥的预拱度设置进行深入分析,并提出不设置活载预拱度的建议。实践证明,不设置活载预拱度减小了线路施工放线难度,更为简便可行。

The concrete girder bridges of high speed railway has a large volume and the proportion of live load in load effect is smaller than dead load.Setting dead load camber is a consensus in engineering circles but there are still differences on whether it is necessary to set live load camber.In fact there are situations of setting live load camber and not setting live load camber in the design of concrete girder bridges of high speed railway.No matter whether the camber of live loads is set or not the railway structure on the concrete girder bridges of high speed railway is constructed according to the elevation of the longitudinal section of the track design.The rail surface is not parallel to the live load camber of the girder surface which deviates from the original intention of camber setting of the bridge.Based on the above reasons this paper makes an in depth analysis on the setting of camber for concrete girder bridges of high speed railway and puts forward some suggestions on the non setting of live load camber.Practice shows it is more convenient and feasible to reduce the difficulty of construction stringing when not set of live load camber.