Experimental Study And Finite Element Analysis On Mechanical Properties Of Prefabricated Reinforced Concrete Composite Beams

With the continuous development of the construction industry,modern buildings gradually develop towards the direction of complex shape and diversified functions.In order to meet the building energy conservation,environmental protection and construction industry transformation and upgrading of sustainable development requirements.Therefore,the design of prefabricated reinforced concrete composite beams appears in a large number of modern buildings.Therefore,it is necessary to study the mechanical properties of prefabricated reinforced concrete composite beams.In this paper,some problems of prefabricated reinforced concrete composite beams are studied,and the mechanical properties of composite beams are discussed under different shear span ratios and different layered height ratios,and the influence of planting bars on the shear properties of composite beams is analyzed.The stress variation law of the mid-span section of the composite beam under the action of load is obtained.The bearing capacity,short-term stiffness,cracks and the height of the laminated surface of the test beam are analyzed and compared.Finally,in the finite element analysis software,select the appropriate damage model and friction coefficient,set reasonable constraints and boundary conditions can get better simulation results,on this basis of the calculation and analysis.Through the study of these problems,it provides reference for the application of prefabricated reinforced concrete composite beams in the construction process in the future.The main contents of this paper are as follows:(1)Under static load test,the failure characteristics,load-deflection curve change and strain change rule of mid-span section of composite beam were obtained.Both the composite beam and the whole cast beam with the same reinforcement have shear failure,and the cracking load and ultimate bearing capacity are less than that of the whole cast beam,but they still meet the design requirements and will not cause the serious reduction of the safety reserve of the structure.The ultimate bearing capacity of composite beams can be effectively increased by planting bars at the joint surface.(2)The theoretical value of ultimate load of composite beams and integrally cast beams has the same variation rule as the experimental value.The crack load obtained by theoretical calculation of the test beam is basically the same,and the theoretical value of crack load is small,but the calculated value is in good agreement with the measured value.(3)The short-term stiffness formula of the whole cast beam can be used to calculate the section stiffness of each test beam.The average crack spacing of reinforced concrete composite beams can be calculated according to the provisions of integral cast beams.Based on the position of the superposition,the causes of horizontal cracks in the superposition are analyzed.(4)The finite element analysis software can calculate the mechanical performance of reinforced concrete composite beam,and the accuracy of the model is verified by comparing the load-deflection curve with the failure phenomenon of the test beam.At the same time,the test data is supplemented by increasing the hoop ratio,which further verifies the accuracy of the model.