Research Of The Interface Slip Of Steel-concrete Composite Beams

Taking as basis the traditional composite beam, Prestressed composite beam's mechanical performance is improved by distributing prestressed bars on steel beam or concrete panel. It is impossible for steel beam and concrete panel of the composite beam to fully work together when they are loaded. The slip at the interference will result in the compositional performance of steel beam and concrete panel decrease, with stiffness of composite beam be decreased and deformation be enlarged, it will also decrease the bending stiffness of the interference of the composite beam. The same disadvantage will show up for prestressed composite beam. Therefore, research on influence of relative slip of interferences on mechanical behavior of prestressed composite beam is necessary.Bending resistance experiments of 9 composite box beams under static loading have been carried out in order to analyze bending resistance performance of prestressed box beam combining steel and concrete taking into the consideration of slip. 8 of them are for bending resistance experiment of prestressed composite beams and the left 1 is for traditional composite beam. The distribution of slip along the beam is depicted by measuring the relative slip. The changing of slipping strain is also detailed by measuring the stress of interferences.Theoretical analyze of mechanical performance of prestessed composite beam under two-point loading is been done in this paper, taking into the consideration of relative slip of interferences and prestress adding. The slip of interferences, slip stress, stress adding, elastic bending resistance and deflection of prestressed composite beam are analyzed and their theoretical values are compared with truth value from experiments.This paper also studies the FEM of interference slip of prestressed beam, with influence of interference slip to mechanical performance of composite beam be analyzed by comparing and calculation of different treatment of interferences.Through above work,this paper get the following conclusions: slip at the interference is almost zero at the middle of beams, the distribution of slip along the half beam shows that slip at both ends is smaller then middle part,and it develop slowly during flexible staged but quickly during elastic-plastic stage;By decreasing compositional performance , bending resistance and enlarging deformation, slip weaken composite beam.It will be more accurate and tends to be safe,once the slip and prestress adding are considered.