Experimental Study On Preformed Steel-concrete Composite Beams

As the hub project of China’s transportation,Bridges play a key role in China’s bridge construction.Steel-concrete composite beam has become one of the common forms of bridge structure due to its reasonable mechanical performance,economical material and light dead weight.Compared with foreign countries,composite beam Bridges in China start slowly,but develop rapidly.In the development of composite beam,in order to respond to the call of national green environmental protection,under the premise of saving materials and convenient construction,how to improve the overall stiffness and overall bearing capacity of composite beam has become a hot issue.At the end of the 19 th century,Chinese scholars returned from visiting Japan and introduced the concept of prebending prestressed composite beams,from which China began to study the structural form of prebending composite beams.In this paper,combined with the design idea of prebending prestressed composite beams,the unidirectional bending method is adopted to make three test beams,one of which is the control group and the other two are composite beams with different precamber of steel beams.A two-point bending static load test was carried out on three test beams.Experimental data such as ultimate bearing capacity,mid-span deflection,strain,beam end slip and slip distribution along beam length were collected.The experimental results of composite beams with different prebending degrees in the control group were compared and analyzed.The improvement of the overall performance of composite beams with this prebending method and the internal relationship between different prebending degrees and the experimental data were explored.Based on the test data,the finite element model of the specimen was established by using large finite element analysis software ABAQUS,and the "double connection" method of bolts and bolts and the constitutive relation model of concrete plastic damage were adopted.The results of the model were in good agreement with the test data.Based on the model,in this paper,the finite element model for the parameter adjustment,including steel steel type,width of concrete flange,concrete strength grade,with the method of the single parameter control variables,mapped the load deflection curve of composite beams under different parameter condition,continue to explore the effects of various parameters on the flexural performance of composite beams.