The Comparison And Analysis About The Design Method Of The Steel-concrete Composite Beam Bridge Between Foreign And Chinese Specification

Steel structure bridge gradually popular because of its high strength, light weight, good plasticity and tenacity, quick construction, easy disassembly and other advantages recently, Steel-concrete composite beam bridge more overcome the high cost of steel structure, easy instability problem, on the basis of play the excellent mechanical properties of steel, becoming a reasonable choice of bridge engineering. However, many content of Specifications for Design of Steel Structure and Timber of Highway Bridges and Culverts guiding the design of steel structure of bridge on the basis of allowable stress method already outdated or incomplete, especially the design provisions of steel-concrete composite beam bridge are too simple and can’t be put into implementation.and code for design of highway bridge steel structure on the basis of probabilistic limit state design method is also under the comments stage, In addition, with the increasing of China’s comprehensive national strength and international influence, a large number of civil construction companies enter to foreign markets, more and more road and bridge projects are constructed by us. Due to differences in climate, geographical conditions, the design and construction of bridge need to refer to multi specification. From the global analysis to the local computation, the load effect to the structural resistance, all countries have different mechanical model and analysis method, this paper compare with the China’s steel bridge design code and American, British, European standard about the Highway steel bridge. The research finds are as follows:1. Compared with foreign codes, China’s Specifications for Design of Steel Structure and Timber of Highway Bridges and Culverts still based on allowable stress method instead of probability limit state design method. Eurocode 4 is a complete expert guidance of steel-concrete composite beam design specification, Design provisions of steel-concrete composite beam bridge had only one chapter in our country, the content can’t meet the requirement of design, need to supplement and perfect;2. Used the knowledge of probability theory, Transformed soving the problem of function which is used to describe the limit state design method into soving the reliability index which is based on the theory of reliability. Derived the relationship between reliability index and safety factor or partial safety factor, and demonstrated that the probability limit state design method represented by partial safety coefficient is advanced than allowable stress method represented by center safety coefficient;3. Calculated and compared the stress of composite steel plate girder and non-composite steel plate girder, We found that the composite steel plate girder’s stiffness and strength are improved. At the same time, deducing the calculation formula of stress on the lower and upper edge under the action of load, and temperature difference, creep and shrinkage, Conducting finite element analysis by the engineering example of the Chiava Bridge, getted the stress situation of steel plate and concrete plate in the construction stage. For steel-concrete composite continuous beam bridge, the negative bending moment is larger, which can make the concrete deck slab tensile stress is too large to crack, especially the impact of temperature, shrinkage, creep effect, We should pay attention in the design;4. Calculated and compared codes of different countries under the vehicle load, creep, shrinkage, temperature gradient load, Found that the internal force under vehicle load has little difference between Chinese and European standards, The British standard is too large, The American standard is too small, Under temperature difference load, effect of Chinese and European standards is less than the American and the British standard, Under shrinkage load, secondary internal force of American standards is too less than the Chinese and European standard, Under creep load, secondary internal force of American standards is too larger than the Chinese and European standard;5. Compared the material properties, the effective width of concrete slab, the calculation of crack width, deflection under normal service limit state and Calculation of shear and bending in the state of ultimate bearing capacity in all specifications. Fond that for the calculation of crack width, China, British, European standard control cracks by limiting crack width, American specification control crack width through the reinforcement spacing, For the calculation of flexural bearing capacity, China, British, European standard use the elastic method, American specification use the plastic method, For the calculation of shear bearing capacity, all specifications only consider the steel beam.