Research On Mechanical Properties Of Joints Of Railway Steel Truss-Web Prestressed Concrete Composite Box-Girder Bridge

As a new type of structure with light weight,strong spanning ability and good economic benefits,composite truss structure has great potential for application in bridge construction in the future.Among them,steel-concrete composite joints are important structures to ensure that the components of composite truss can work together.However,there is still a lack of research on composite joints in China,which makes it difficult to popularize the use of composite trusses.Based on the background of the first railway steel truss composite box-girder bridge in China,combined with model tests,the mechanical properties of steel truss composite box girder joints are studied.The main work is as follows:(1)Based on the basic theory of non-linear analysis of reinforced concrete structures,the material constitutive model,element selection and parameter setting of solver of finite element model are introduced in detail.At the same time,the validity of the finite element modeling method is verified by comparing with the existing experimental results.(2)ABAQUS software is used to simulate the whole loading process of composite joints under hydrostatic loads.The load-displacement curve,the stress-strain distribution of each component are obtained.The characteristics of the joints and the way of load transfer are also analyzed.(3)The single parameter analysis method was used to analyze the factors affecting the mechanical properties of the joints,and the specific effects of different parameters on the mechanical properties of the joints were obtained.(4)By using orthogonal test method and taking the mechanical properties of the joints as the index,the optimum analysis of the joints is carried out,and the influence degree of each factor and the optimum combination of factors are obtained.