Analysis And Calculation Of Reinforced Stone Arch Bridge

Stone arch bridge has nice modeling,low cost,great carrying capacity,accounts a large proportion of small and medium size bridges.Especially in southwest China,with plenty of stones,many masonry arch bridge was built at early stages.These bridges have been put into operation for a long time,bridge performance decreased.And with the increasing traffic,many of the early construction of the bridge has been unable to meet our requirement.However,it is obviously that a lot of time,manpower,material and financial resources will be consumed if we tear down and rebuild all these bridges.So,it is significant to reinforce and maintain these old stone arch bridges.There are various ways of bridge reinforcement,but the most common method of reinforcement for stone arch bridge is enlarging section.Enlarging section reinforcement refers to add a new arch above or below the old arch,to increase the cross-section of the main arch,and improve the carrying capacity of the main arch.Increasing the cross-sectional structure of the bridge after strengthening belongs to composite structures by the new and old arches,with the mechanical characteristics that to be forced in two stages,which is different with single arch.Reinforced bridges have been carrying loads for a long time before reinforcement,the structure is already in a state of initial stress and strain.The new arch began to carrying loads after the formation of strength,so the stress and strain of the new arch will always been lag behind with the old arch.When the structure reaches the limit state,it is the old arch that reach the limit state first,the carrying performance of the new arch would not be fully play out.Through the model test and finite element analysis,it is been found that when calculated and analyzed for reinforced structure,if the initial stress state of the old arch did not be considered,the calculation result of the carrying capacity would be too large,the stress analysis of the whole structure would be affected too,especially to the deformation and strain.This paper is based on the mechanical characteristics of reinforced stone arch bridge by enlarging section method,by the way of experiment,finite element analysis,theoretical analysis,etc.,give full consideration to the initial stress condition of the old structure before reinforcement,while consider the non-linear stress-strain constitutive relationship,under the basic assumptions that the failure mode of reinforced structure is small eccentric compression failure,calculation methods of carrying capacity for reinforced bridge has been derived,and reasonable assumptions about load effect combination method for strengthening structure had been put forward.In the end,based on the considerations of making the calculation more simple,this paper put forward the idea of carrying capacity correction coefficient is used to correct,through conversion section,put the reinforced structure into calculation as a whole,and then correct the results with the correction factor.