客运专线铁路预应力混凝土连续梁底板崩裂加固设计

某客运专线(30.15+48+56+48+30.15)m预应力混凝土连续梁在预应力张拉、压浆完毕后中孔56 m梁底发生了较大面积的崩裂。综合分析崩裂原因,通过对各种"传统补强"方案在加固设计中的利弊分析、对比,结合预应力管道已压浆完毕的现实状况,提出一种新的加固设计方案——梁体施加预压荷载方案。该方案从连续梁的受力特征出发,突破了传统方案只在通过"补强"方面作文章的思路,有效避免了传统方案的弊病,取得了较好的补强效果。

Design for Strengthening Treatment of Bursting Cracks at Bottom Slab of Continuous Prestressed Concrete Girder of Railway Passenger Dedicated Line

After the processes of prestressing and grouting were both finished for a(30.15 + 48 + 56 + 48 + 30.15)-m continuous prestressed concrete girder of a railway passenger dedicated line,the phenomenon of large-area bursting cracks occurred at the bottom slab of its 56-m middle span.Therefore,the paper comprehensively analyzed the reason of bursting cracks,and conducted relevant investigation and comparison on the advantages and disadvantages of various traditional strengthening methods.Further,considering the actual situation that the duct grouting of steel tendons had been finished already,the paper put forward a new design scheme of strengthening treatment—preloading to this girder structure.This new design scheme,focusing on the stress state of continuous girder,and breaking through the idea of traditional methods which only lay emphasis on "strengthening ",has effectively avoided the disadvantages of traditional methods.Finally a good strengthening treatment effect has been achieved by using this new design scheme.