Research On Mortise And Tenon Joint Design Of Fabricated Hollow Slab Bridge

After continuous development and improvement,the prefabricated hollow slab bridge still presents many problems,most of which are hinge joints.The failure of hinge joints weakens the ability of transverse connection,which will directly lead to excessive stress on the single slab of the bridge.When the hinge joints are damaged,a single slab will bear more load,which is unfavorable to the structure.When hinge joints are completely destroyed,it will directly lead to single plank bearing,and if it is serious,it will lead to the collapse of the bridge.Therefore,it is particularly critical to solve the transverse connection problem of the prefabricated hollow slab bridge.Although many scholars have studied the damage problem and reinforcement method of transverse hinged joints,the nature of cast-in-place hinged joints as transverse structure remains unchanged,and the problem of transverse connection has not been substantially solved.Therefore,this paper proposes a new type of transverse connection form "mortise and tenon joint" of prefabricated hollow slab bridge,which avoids the use of cast-in-place hinge joint structure,and through the mechanical bite force of the mortise and tenon joint structure between two adjacent hollow slab to achieve the purpose of transferring shear force.At the same time,it is applying the transverse prestress that can improve the structural integrity,which effectively solves the problems existing in the transverse connection of fabricated hollow slab Bridges.Through the theoretical analysis and numerical simulation of the new joint structure,the design and calculation of the structure are studied.This paper first introduces the basic principle of finite element software in modeling,analyzes the advantages and disadvantages of ANSYS in structural analysis,defines the element characteristics and constitutive relations of various materials,and points out the simulation method of prestressed steel bar.Solid65 is adopted to simulate concrete,and matters needing attention in material parameter setting and properties are proposed.The simulation of the transverse connection of concrete between two adjacent slabs is the key point of structural stress,and the key points of concrete contact modeling and the matters needing attention in parameter setting are put forward.The results show that the modeling effect is better by selecting units and setting model parameters,and the validity of the modeling results is verified.Secondly,the influence range of precompression stress of mortise and tenon structures under transverse prestressing is studied.The mechanical behavior of the structure under transverse prestress is analyzed through ANSYS modeling,and the influence range D of prestress under transverse prestress is obtained.The influence range of span on prestress is obtained.Through the analysis of the change rule of transverse prestressed bar spacing and magnitude of prestress,the determination method of transverse prestressed bar spacing and magnitude of prestress is obtained.The results show that the transverse preloading range D is between 4.0 and 5.0 meters,and the stress concentration at the joints can be better solved when the spacing of transverse prestressing bars is 1/2D,and the transverse stress is obviously linear superposition.The optimal design scheme of mortise and tenon structure is obtained by analyzing the parameters of mortise and tenon structure with different spans by using finite element method.The range of mortise and tenon sizes is suggested to avoid premature cracks and ensure the load capacity of mortise and tenon structures.The results show that the mortise and tenon Angle should be less than 45° and the width D should be between 15 cm and 20 cm.Finally improved transverse connection of prefabricated hollow slab true bridge modeling analysis,first of all to the design of transverse prestress and the reasonable size of mortise and tenon joint,and the stress analysis of bridge finite element model is established.The results show that: the transverse with mortise and tenon joint of prefabricated hollow slab bridge under the action of load and partial load of stress is better compared to the transverse connection of the hinge joints in hinged with traditional prefabricated hollow slab bridge,and hollow slab bridge stress is more uniform after improvement,coordination between various plate stress effect is good,which can well solve the problem of excessive solvating at all from the design of the improved method solving the problem of hinge joint diseases.The results show that the new mortise and tenon joint mode of prefabricated hollow slab bridge can effectively solve the problems existing in the transverse connection of prefabricated hollow slab bridge,and has certain engineering application value.