Experimental Study On Mechanical Behavior Of Precast Composite Wall With Horizontal Joints And Dry Joints

Precast composite wall structure is an eco-energy-saving building structure system adopting industrialized construction mode,which meets the requirements of environmental protection policy and sustainable development advocated by the state.With the development of precast composite structure to a higher level and a wider scope,the dry connection technology of precast composite wall board boundary has become a key issue in the application of structure promotion.This paper proposes a green-precast composite wall structure system based on the new dry connection technology.The experimental research,numerical simulation and theoretical analysis are combined to study the key problems from the perspective of components.The main contents and achievements of this paper are as follows:(1)Quasi-static tests of four assembled composite walls with different horizontal joints(sleeve grouting connection,welded joint,box connection,bolted connection)was completed to study the seismic performance of precast composite walls with different horizontal joints,such as bearing capacity,stiffness,hysteretic performance,ductility and energy dissipation capacity.The test results show that the failure mode of each test piece is shear-type failure.Compared with sleeve grouting connection,the performance of welded connection is slightly weaker and the requirements of welding technology are higher.The box-type connection is equivalent in bearing capacity,since the box connection is only arranged on both sides of the rib column,its stiffness,ductility and energy consumption are worse.The bolt connection is slightly lower in bearing capacity and rigidity,and superior in ductility and energy consumption.(2)The monotonic loading test of five precast composite walls with horizontal joints and bolted joints was completed to study the effects of different high-strength bolt specifications and thickness of connecting steel plates on the bearing capacity,stiffness,ductility,strain of connecting steel plates,and direct vertical slip between embedded parts and connecting steel plates.The test results show that the bearing capacity,stiffness and ductility of the specimen increase with the increase of the thickness of the jointed steel plate,and the bolt specification has less influence on it.The main performance is that the bolt specification is more uniform and the ductility of the wall is better.The steel plate connected to the pressure end is coordinated with the concrete before the slippage occurs,and the internal force is transmitted together.After the slip occurs,the compressive stress in the compression section is mainly transmitted by concrete.The test piece is transmitted by the friction of the bolt before the bolt is in contact with the embedded part and the connecting steel plate.Before the bolt contacts with the embedded part and the connecting steel plate,the connecting parts at the tension end of the specimen pass through the concrete.The friction of the bolt carries on the force transmission.After the contact,the force is mainly transmitted through the pressure of the screw.(3)The ABAQUS finite element software is used to model and calculate the assembled composite wall with bolted horizontal joints,which verifies the rationality and reliability of the model.The parameters of high-strength bolt specification,thickness of connecting steel plate,joint arrangement and axial compression ratio are expansively analyzed.This paper also analyzes its influence on the bearing capacity of the specimen and the slip of the joint.The results show that the bigger the diameter of high strength bolt,the more thickness of connecting steel plate,the ratio of axial compression,the greater the strength of the block and the higher the reinforcement ratio,the greater the bearing capacity.At the same time,the bigger the diameter of high strength bolt and the bigger the ratio of axial compression,the later the slip of connecting parts occurs.(4)This paper analyzes the failure mechanism of precast composite walls with bolted joints,and considers the contribution of bolted joints to the shear strength of the wall.The simplified calculation model of the shear capacity of the wall is established by the theory of shearing,and the contribution of key parameters to the shear capacity of the wall is studied.In this paper,the formula of the shear bearing capacity of the precast composite wall with bolted joints for horizontal joints is given.