Difference Analysis Of Design Codes Between China And Europe For Railway Reinforced Concrete Frame Bridges

The rapid development of railway construction in China is accompanied by the implementation of the policy of"the belt and road".Domestic enterprises are becoming more and more normal in undertaking foreign projects.However,foreign projects are mostly in the original European and American colonies,leading to domestic designers being required to design railway bridges by using local design codes or European standards.This paper analyzes the differences between the two design specifications based on the Chinese railway bridge design code for allowable stress method and the European code for the limit state design method.It is hoped that on the one hand,it can help engineers involved in foreign railway bridge design,on the other hand,it can provide reference for the development of our railway bridge design code from allowable stress method to limit state method.The main research work of this paper is as follows:(1)The basic design criteria of the two codes are compared and the European limit state design method is introduced.(2)Summarize the different stipulations of the two standards for the strength standard values and elastic modulus of concrete and steel materials commonly used in reinforced concrete structures,and introduce the material allowable stress of Chinese railway bridge design code and material strength design value of European code respectively,and compare and analyze the material design indexes of the two codes.The different load classification methods of the two specifications and the different values of the load related to the railway reinforced concrete frame bridge structure are described.(3)Introduce the different basic assumptions and equivalent stress diagrams of flexural members in the two codes.According to the definition of relative limit compression zone height,the relative limit compression zone heightξ_b of railway bridges in China is given.Comparing the requirements of the two codes for maximum and minimum reinforcement ratio of flexural members,the bearing capacity of the two codes under the same reinforcement ratio and the required reinforcement area under the same load are analyzed.the change of flexural bearing capacity with reinforcement ratio and concrete strength grade in the two codes is also studied;the different formulas for calculating axially and eccentrically loaded members in the two codes and the different requirements for the second-order effects in the two codes are given,and the variation of the axial compressive bearing capacity of the two codes with reinforcement ratio and concrete strength grade is studied.This paper expounds the different stipulations on the thickness,crack width and deflection of concrete protective coat in China Railway Bridge Design Code and European Bridge Code.(4)Taking the frame bridge as an example,the finite element model is established by using the finite element software Midas/Civil 2019 to analyze the load effect of the two codes under the same load.The steel reinforcement design of the top and bottom of the frame bridge is carried out by using the Chinese Railway Bridge Design Code and the European Code respectively,and the difference between the two codes under the same load is compared.