Seismic Behavior Of Assembled Shear Wall With FRP Constrained Vertical Reinforcement Connections

Under the concept of sustainable development advocating green environment protection,modern architecture should develop with the times and adapt to the needs of industrialization,industrialization and modernization of contemporary society,fully utilize and bring into play the characteristics of new materials and structures,the core objectives are to create new architectural styles,improve the quality of buildings,improve building productivity and uphold the concept of green construction.Prefabricated building structure is one of the typical forms of modern building structure in China and even in the world,the key technology of prefabricated prefabricated structure is the safety and reliability of the joints,so as to ensure that the whole structure has good seismic performance.Grouting sleeve connection and restrained grouting anchor connection are two widely used reinforcement connections in assembled concrete structures,although it has been widely used in the component connection of many assembled concrete structures,there are still some drawbacks,such as difficulty in construction,difficulty in controlling grouting quality,high cost,difficulty in collapse and hole punching,which need further improvement.In this paper,a new connection method of steel bars in assembled shear wall joints is proposed,which is called "overlap connection of steel bars with FRP constraints".The purpose is to make a better performance balance between the cheapness and reliability of the connection of steel bars.Three shear wall specimens were designed and fabricated,and two research methods,pseudo-static test and numerical simulation based on OpenSees software,were adopted,complete the following work and draw the corresponding conclusions:(1)Firstly,the vertical connection forms of assembled shear wall structure are summarized,and the advantages and disadvantages of each connection form are analyzed.Then,based on this,a new method of joint connection with FRP restrained overlapping reinforcement is proposed.The relationship between the length of overlapping reinforcement and the diameter of reinforcement is determined according to reliability theory through two groups of basic tests,such as anchorage of reinforcement and overlapping of reinforcement.(2)The quasi-static test is carried out on the assembled shear wall specimens connected by the joints.In the test,the influence of the parameters such as the diameter of steel bars,the overlap length of steel bars and the equivalent relationship of steel bars on the seismic performance of shear wall structures is mainly considered.The results show that:In the new connection area,there is necking phenomenon of the connecting steel bar before it is pulled off.There is no slip between FRP restraint ring and internal grouting material or external concrete,and the structure of FRP restraint ring is not destroyed.During the whole loading period of the specimen,there is always a restraint effect on the internal grouting material.The load-displacement hysteretic curves of the three shear wall specimens are full,showing good energy dissipation capacity,bearing capacity,stiffness and ductility.(3)Three shear wall specimens are modeled by OpenSees program to simulate the seismic behavior of cast-in-situ shear walls with the same reinforcement under the same reciprocating load.The comparison between numerical simulation results and experimental results shows that the hysteretic curves of the two methods are in good agreement,which indirectly proves that the new joint connection method proposed is equivalent to the cast-in-situ connection method,and can ensure that the shear wall has better seismic performance.