Research Of Concrete Shrinkage And Creep Effect On Long-term Performance Of Steel-concrete Composite Beam Bridges

The steel-concrete composite girder bridge connects the two materials with different properties of the steel girder and the concrete bridge deck into one piece through the shear connectors,so that the performance advantages of the concrete and the steel are complementary,and the advantages of the steel and the concrete are fully exerted.It is getting more and more widely used in modern bridges.However,concrete has the effect of shrinkage and creep that changes with time,and there are many internal and external factors that will have unpredictable effects on the safety and durability of the overall steel-mixed composite structure.In this paper,based on the examples of steel-concrete composite continuous beam bridge project,a finite element analysis model is established to study the effect of concrete shrinkage and creep on the long-term performance of steel-concrete composite beam bridges.First of all,this article gives an overview of the status quo of research on the domestic and foreign development of concrete shrinkage and creep and steel-concrete composite girder bridges,and gives a brief analysi s.Then,the mechanism of concrete shrinkage and creep generation and its classical calculation theory and methods are reviewed,and the advantages and disadvantages of several classic theories are compared.Then,the steel-concrete combination continuous box girder bridge engineering example was selected and its finite element model was established using Midas Civil finite element analysis software.Secondly,the finite element model was used to analyze the influence of shrinkage and creep on the concrete bridge deck and steel box girder deflection and stress.Including the full-bridge deflection and stress distribution law,the characteristics of the section at the top and bottom edge of the deflection and stress changes over time and the law of change and magnitude.The analysis results show that the shrinkage and creep of concrete has a great influence on the steel-concrete composite structure.Attention must be paid to the design and construction of the steel-concrete composite beam bridge.Finally,the three parameters affecting the shrinkage and creep effects of concrete,shear stiffness of shear bolts,theoretical thickness of concrete decks,and the average annual humidity of the environment were analyzed.The influence of these three parameters on the long-term deflection and stress of the steel-concrete composite girder bridge is summarized,which provides a reference value for the impact of concrete shrinkage and creep on the advantages and disadvantages of the concrete in the design and construction of steel-concrete composite girder bridges.