Study On Mechanical Properties Of T-Beams Strengthened By Steel Plate-Concrete Composite Reinforcement Considering Slip Effect

The steel plate-concrete composite reinforcement is a new method developed from the steel-concrete composite structure theory.The original structure is reinforced by welding the ribs and welding the stud connectors on the reinforced steel plate,and then the concrete is poured between the steel plate and the original structure to connect the reinforcing portion with the original structure.The steel plate-concrete composite reinforcement is a promising method due to its good performance in mechanical properties,construction performance and economic performance.The slip effect of the interface between the reinforced steel plate and the reinforced concrete in the composite reinforced concrete T-beams and its influence on the reinforcement effect were studied based on the theoretical analysis,experimental research and finite element numerical simulation.The main work of the paper is as follows:1.Based on the basic theory of steel-concrete composite structure,considering the slip effect of the interface between the reinforced steel plate and the reinforced concrete,the calculation formula of the slippage of the interface and the deflection of the composite reinforced beam and the ultimate bearing capacity of the bending were established.2.Based on the actual reinforcement project of a T-beam bridge in Hubei Province,the bearing capacity test of 7 reinforced beams and 2 original beam was designed by changing the reinforcement parameters such as shear joint strength,reinforcement length and reinforcement steel plate height.The process failure mode and steel strain,concrete strain,deflection,slip,etc of the test was analyzed and demonstrated in detail.3.Based on ANSYS,the finite element model was established for the simulation of whether or not to consider the slip effect.Through the comparison of the finite element model data of the two connection modes of the test beams,the influence of the slip effect of the interface between the reinforced steel plate and the reinforced concrete on thesimulation results was analyzed.The effects of different shearing joints,length of reinforcing part and height of reinforcing steel plate on the slip effect and reinforcement effect were also analyzed.4.Through the comparative analysis of the theoretical calculation value,experimental measurement value and finite element calculation value of the combined reinforcement beams,it was demonstrated that the theoretical calculation method given in this paper can accurately calculate the ultimate bending capacity,the slip and vertical deflection of the composite reinforced beam.The finite element modeling considering the slip effect can effectively simulate the true stress state of the composite reinforced beam and evaluate its stress characteristics and reinforcement effect.Through the analysis and evaluation of the influence of different reinforcement parameters on the slip effect and the reinforcement effect,the optimization proposal of the reinforcement design scheme was given for considering the original beam state and reinforcement requirements.