Finite Element Analysis Of Partial Concrete-filled Steel Box Continuous Composite Beams With Influence Of Bond-slip Behavior

Traditional steel-concrete composite beam can take full advantage of the strength of the materials under the positive bending capacity since it is made up of concrete slab and steel beam through shear connectors.But concrete slab is easy crack due to its low tension strength,while the steel beam based on the section compressive zone,is failure to use the ultimate bearing capacity due to the stabilization problems under negative bending moment.So solving the bearing capacity and crack controlling problem is the key.Based on the above reason,partially concrete-filled narrow-width steel box composite beams is proposed.It is made up of concrete slab and partially concrete-filled narrow-width steel beam by shear connectors.By filling concrete at the greater compressive zone,it can improve the performance under stress on the middle zone.Based on the experimental study of partially concrete-filled narrow-width steel box continuous composite beam,the precise modeling analysis was built by using finite element software ABAQUS.Considering the nonlinearity of material,geometric nonlinearity and contact nonlinearity factors,it simulated the performance under stress of the negative bending moment zone of the continuous composite beam under the condition of two-point symmetric concentrate loading.The simulation results is extremely close to the testing results,which verifies the effectiveness of the model.In order to analyze the statics performance of partially concrete-filled narrow-width steel box continuous composite beam,I use the nonlinear spring 2 to simulate the bond-slip and shear connector between steel box beam and concrete.It can tell us the difference if we consider with the bond-slip or without it under the following factors.Such as different strength grade of concrete slab,the reinforcement ratio of concrete slab on different negative bending moment zone and the thickness of steel box beam plate(roof,web and floor).It comes to a conclusion that if the degree of complete shear connection is adopted in the engineering design,the relative slip between the continuous composite beam wing plate and the steel beam can be neglected,so as to simplify the calculation.In addition,by increasing the thickness of the steel beam web or the bottom plate,the ultimate bearing capacity and stiffness of the partially concrete-filled narrow-width steel box composite beams can be effectively improved.The nonlinear finite element simulation under different degree shear connection and diameter of stud and bolt dedicated that if we use the stronger shear connection or smaller diameter of stud connector,it will improve the compression resistance and tensile strength of the materials.It can also increase the bending stiffness of composite beam.The ultimate bearing capacity can be improved and the relative slippage can be reduced with the stronger shear connection.Take the initial imperfection,geometric and material nonlinearity into consideration,Riks Method was used to simulate the shear buckling of partially concrete-filled narrow-width steel box continuous composite web beam.The results show that partial shear buckling destruction will appear in the junction between positive and negative bending moment when web beam is under the shear stress.we can set the bearing stiffener in this zone to relieve the partial shear buckling destruction occurrence.