Load Transverse Distribution And Flexural Capacity Of Steel-concrete Composite Beam Bridges

Steel-concrete composite girder bridge can give full play to the advantages of steel and concrete,and gradually increase in the application of medium and small span bridges.In this paper,the bridge structure composed of multiple steel plate beams and concrete panels is deeply studied from the lateral distribution coefficient and the calculation method of the bending capacity.Firstly,in the calculation of the lateral distribution coefficient,combined with the traditional simplified calculation methods of transverse distribution;coefficient of load commonly used in prefabricated structure bridges(such as the rigid beam method,the rigid beam method)and the finite element analysis method,the typical loading in the span of the simply supported beam is carried out.The vehicle load method compares the difference between the traditional method and the finite element analysis results to determine the accuracy and applicability of different algorithms for the composite beam bridge calculation.The results show that:(1)In the traditional simplified calculation method,the straight-slab beam method has better applicability to the calculation results of the lateral distribution coefficient,and the maximum deviation is about 15%,which is safer and acceptable.(2)The results of beam-grid method are close to the solid finite element method,and the deviation is about 3%-5%.This method is simple,efficient and reliable,and it is recommended.Secondly,the influence of factors such as steel-sand interface slip,beam layout and bridge deck thickness on the transverse distribution coefficient is further analyzed,and the degree of influence on the transverse distribution calculation results is revealed.The calculation results of transverse distribution coefficient under different factors show that the results increase by about 5% when considering the interface slip effect,and the relative height of the cross beam to the bridge deck has little effect,while the effect of the beam arrangement on the result is only that the whole bridge is not set horizontally.When the partition is increased by 15%,the deviation of the calculation results of other different beam spacing is smal.In addition,combined with the norm,the applicable conditions of the elastic analysis method and the simplified plastic analysis method are compared in the calculation method of the bending capacity of the steel-concrete composite girder bridge,and the calculation method of flexural capacity of composite girder bridge is deduced based on elastic theory and plastic theory.Through calculation examples,it can be found that the plastic flexural capacity is increased by about 20%-30% compared with the elastic flexural capacity.At the same time,the influence of time-varying effect on structure in elastic analysis method is discussed in this paper.Considering the long-term creep effect,the stress of steel beams increases by about 7%.