Study On The Mechanical Characteristics And Optimal Structure Of Integral Bridges Abutment-Pile Junction

The abutment component is very important to convey deformation and internal force from superstructure to substructure,and the key question for integral abutment bridge's designing and computing.In order to solve two critical problems: pile cap-H pile junction's design and compute method,and the optimal abutment-pile composite junction connection,this paper using theoretical analysis and numerical simulation to study the analytical boundary condition of H pile – abutment joint,the failure mode of composite junction,the optimal junction connection etc.The results show that:(1)the single pile analysis model considering structuresoil interaction can better reflect the actual stress and deformation boundary conditions of the joint section.The finite element analysis of the single pile model is accurate when studying the bearing capacity of the abutment joint.(2)The integral abutment joint may lead to two failure mode: local failure and punching failure.By researching related parameters such as pile embedded length and abutment thickness,the critical stress is obtained,and the estimation method of pile – abutment composite junction capacity is established.(3)By the computing result of pile cap stress distribution,suggested that in the steel pile and concrete abutment steelconcrete junction should set the PBL connecting members in order to avoid the cracks' expansion and development on the interface,and to enhance of the plastic deformation capacity of the structure.The research productions are applied to one IAB project,and the structure's internal force and deformation result are acceptable,meanwhile the construction difficulty and maintenance cost are reduced,which showed that the integral design is with good economictechnology property,and worth being expanded.