Study On The Performance Of Fabricated Frame With High Strength Bolt Connection

Prefabricated concrete structure is an important structural form to realize the further development of China’s construction industry.Prefabricated concrete structure has many advantages such as environmental protection,energy saving,short construction period and so on.It is a new type of structure which is widely accepted by the industry and is in line with the development of our country.To ensure the seismic performance of prefabricated concrete frame structure is the most important task to promote the development and application of prefabricated concrete frame structure system.In this paper,a new prefabricated high-strength bolt joint connection method is proposed.The new joint embedded steel member at the beam end is connected with the column through high-strength bolts,which can improve the strength and ductility of concrete in the core area and the bearing capacity of the frame.The idea of "strong beam" is realized by setting the joint at the beam end.In order to verify the feasibility of the new high strength bolted joint,the method of combining test and finite element simulation is adopted in this paper.The seismic performance of the fabricated high-strength bolted joint is systematically studied.The main research works include:1.Design and production of prefabricated high strength bolt connection node scale model of frame structure,at the same time make the traditional cast-in-situ frame structure for comparison,in order to research the seismic behavior of the fabricated nodes,under low cycle reciprocating load,using the research method of aseismic test experiment phenomena of the specimen,bearing capacity,hysteresis curve,skeleton curve,stiffness degradation,ductility and energy dissipation were analyzed.Compared to two kind of experimental phenomena of the specimens,cast-in-site frame structure and modular structure both in the first level 4 first crack appeared in the process of cyclic loading,and construction of cast-in-situ forward and reverse the cracking load of 31.29 KN and 19.96 KN,prefabricated structure of forward and reverse 33.18 KN and cracking load of 21.07 KN,cast-in-situ cracking time before the assembled structure of the structure,shows that the bearing capacity of cast-in-place structure is slightly lower than modular structure.Two kinds of members are in "S" type the hysteresis curve,showed good seismic performance of the specimens,comparison and analysis to fabricated framework of positive and negative direction area of hysteresis loop back contains more full than cast-in-situ framework,the overall work performance is slightly better than that fabricated structure cast-in-site frame structure,cast-in-site frame structure of ductility coefficient is 3.28,the ductility coefficient of precast frame structures is 3.45,two types of ductility coefficient of the specimens were greater than 3,the ductility of the specimen is good,but a comparison size fabricated the ductility of the frame structure is better than that of cast-in-situ frame structure.2.The low-cycle reciprocating loading simulation was carried out on the fabricated highstrength bolted joint frame and the cast-in-place joint frame by finite element software,and the simulation results were compared with the test results.The results showed that the hysteresis curve and failure state of the model were in good agreement with the test results,and the reliability of the calculation model was verified.3.After verifying the reliability of the software simulation,the finite element simulation was carried out by changing the axial pressure ratio and strength grade of the high-strength bolt in the model,so as to analyze the influence of these parameters on the skeleton curve,stiffness degradation and other seismic performance of the specimen.