Study On A New Beam-Column Joint Of Fully Precast Concrete Frame Structures

In recent years,China’s Ministry of Housing and Urban-Rural Development has issued a series of construction industrialization documents.The purpose of this documents is to promote the development of China’s residential industrialization,and prefabricated buildings are an important way to effectively promote the development of residential industrialization.so the prefabricated building is the general trend of the development of China’s construction industry.The prefabricated concrete frame beam-column joints are the assurance of the building structure’s quality.So how to properly design the beam-column joints is very important for the entire building structure system.In the study of fabricated concrete beam-column joints,the connection of column-column and beam-column is very important.They connect the various components of the entire building structure to make the joint parts work together.The seismic performance has a great impact with these joints,so it is of great significance for the study of the seismic performance of precast concrete beam-column joints.Based on the existing research results at home and abroad,the following research work is carried out on the new joints of sleeve grouting connection,bolt connection and hybrid connection by numerical simulation:1)Designed column-column connection and beam-column connection,wherein the column and column are connected by sleeve grouting,and the dark-legged legs,bolts and steel are connected between the beams and columns,and the force analysis of the joints is carried out;2)For the designed joints,the low-cycle reciprocating loading simulation on the beam-end is simulated under different axial compression ratios,and the cast-in-place joints under the same conditions are simulated,and the monotonic loading simulation on beam-end of each model is carried out at the same time;3)The data analysis of the fabricated beam-column joints is carried out from the aspects of hysteresis curve,skeleton curve,ductility,energy consumption and stiffness.The performance of the cast-in-place joints and fabricated joints are compared.The bending moment-turn curve of the end of the core of the joint under the monotonic loading of the beam is proposed,and the corresponding rotational stiffness is obtained;4)Using the PUSHOVER analysis module of SAP2000,the seismic analysis of the full precast concrete frame structure under the new beam-column joints is carried out.This paper draws the following main conclusions:1)The new assembled concrete beam-column hybrid joints are slightly different from the cast-in-place joints in seismic performance.The bearing capacity of the new assembled joints loaded at the same axial compression ratio is slightly higher than that of the cast-in-place joints.The ductility is higher than that of the cast-in-situ joints.The energy consumption is lower than that of the cast-in-situ joints,and the stiffness degradation is slower than that of the cast-in-situ joints.2)By analyzing the rotational stiffness of the end of the core of the joint under the axial compression ratios which is 0.2,0.25,0.31,and 0.4,it is concluded that the rotational stiffness of the fabricated joint increases as the axial compression ratio increases.3)Under the multiple earthquakes and rare earthquakes,the apex displacement and interlayer displacement angle of the full precast concrete frame structure of the new beam-column joints meet the seismic requirements.