Research Of Disease Analysis And Reform Of Reinforcement And Widening Of Double Arch Bridge

Double arch bridge is an exclusive bridge in China,and an achievement of wisdom of Chinese.Double arch bridge has many obvious advantages,such as saving material,simple constructing,low cost,so on and so forth.Double arch bridge has been widely used throughout the country in a short period of time because of its fitness with the national conditions and technology level.But with the growth of time and the economic development,most of the existing doublecurved arch bridge has been unable to meet the current traffic volume,which was listed as dangerous old bridge.Consequently,its transformation becomes imminent.In this paper,two problems are studied,first is strengthening and widening of double arch bridge,second is the problem of shrinkage and creep of concrete which is one of the unsolved problems of bridge widening at present.According to actual situations of Shuixi Bridge,Jianyang District,Nanping City,Fujian Province,this paper mainly conducts following studies:(1)A full introduction of common problems of old double arch bridges and current common reinforcement and reform methods.(2)Reinforcement method of original Shuixi Brdige is to add concrete on surfaces and filling cores.According to Midas/civil model-building,this reinforcement method effectively refors orginal Shuixi Bridge and improves comprehensive capacity of the brdige.(3)Original Shuixi Bridge is not of super large sized double arch bridge.Based on position of center line after reform,bilateral asymmetry widening method is adopted and extra parts are linked with existing bridge.For extra parts,prefabricated boxed-shaped ribs are used,similar to part of sections of original bridge after reform.After calculation,this method is proved to be effectively used in original Shuixi Bridge.(4)The paper proposes to set wet joints between original and new bridge.Wet joints are required to be constructed after completion of upper structure and before deck pavement.This avoids damage to sections due to difference of shrinkage creep between arch rings of original and new bridge.(5)This paper mainly explores influences of difference of shrinkage creep of concrete on ribs of new and original bridge.It is found that influence of difference of shrinkage creep on joints between new and original concrete is much stronger than that on areas awary from joints.In respond to such problems,the paper proposes two suggestions:slowing down connection of new and original bridge for enough steady time for concrete of new bridge;adding swelling agents into concrete as to reduce shrinkage.