Experimental And Theoretical Study On New Assemblies Of Prefabricated Prestressed Concrete Beam And Column

With the rapid development of China's economy and the continuous improvement of technical level,the assembly structure has become one of the main developing directions of the construction industry.Confined concrete structure can take full advantage of the compression performance of concrete to improve the strength and ductility of the components.Based on the advantages of the two structures above,this paper presents a new assembly of prefabricated prestressed concrete beam and column with bolted end-plate,and its seismic performance is studied.The main research contents and achievements are as follows:?1?The quasi-static tests of 14 new assemblies and 1 cast-in-place joint were conducted.The failure modes,strength,stiffness,ductility,energy dissipation capacity and classification standard of assembles were analyzed.The results show that the strength and rigidity of the new assemblies are high,the ductility and energy dissipation capacity are close to that of the cast-in-place and their joints are rigid joint.?2?The connection of the new assemblies and the economics of the high-strength stirrup were analyzed.The results show that the pier head of ordinary longitudinal reinforcement is reliable at the welding connection satisfied with the formula ???.The safety reserves of the welding-plate are high by use of groove welding.The end-plate welding steel-strip locally can effectively improve its bending performance.When the weight ratio of high-strength stirrups to ordinary stirrups is less than 2 and the average confined stress is close,the use of high-strength stirrups is more economical.?3?Based on the truss+arch model modified variable angle,considering the confined effect of the spiral stirrups and prestress,the theoretical formula of the beam shear capacity are deduced,in which including the angle ?'of the ribs of the equivalent rectangular stirrups,the ratio ? of shear to span,the confined concrete compression strength f_cck,the pressure zone height x of the arch and so on.According to the actual situation of construction,the theoretical formula is simplified and the simplified formula is V_u=?_svbf_svh_s+?1-??'?Vf_cckb?h.The formula is verified by the shear failure test data of high-strength stirrups specimens.The results show that the calculated values are in good agreement with the experimental values.