Research On Seismic Performance Of New Fabricated Reinforced Concrete Frame Beam-column Joints

Prefabricated concrete structure is an important structural form to realize the development of building industrialization.it has the advantages of construction convenient,energy conservation and environmental protection,safety economy and so on,which is recognized as the new-style structure that can be suitable for China’s national conditions and has a wide application prospect.Therefore,To ensure the seismic performance of precast column-to-beam joints is the key to develop and promote the prefabricated concrete frame structure which is the most widely used prefabricated structural system due to its high rate of prefabrication.This paper proposed a new connection method of precast column-to-beam joints for prefabricated concrete frame structure.Its precast beam and column was connected by embedded profile steel with high strength bolts that could be regarded as the hidden corbel,and it used angle iron to be the energy dissipation component of the joint.The nonlinear finite element analysis software ABAQUS was used to analyze the seismic performance between the prefabricated joint and the cast-in-situ one under low cycle reciprocation.The mechanical properties of the prefabricated joints proposed in this paper are comprehensively analyzed by comparing the failure modes,stress distributions,hysteresis curves,energy consumption curves,ductility,strength and stiffness degradation curves to the cast-in-situ one.The result showed that the hysteresis curves of the new type precast column-to-beam joint is spindle shape which means it has good ability of plastic deformation.The energy consumed by prefabricated joint was greater than the cast-in-situ one under low cycle reciprocation and its ductility was better.The load capacity of the prefabricated joint under the yield state,limit state and failure state was higher than the cast-in-place one.And its strength and stiffness degradation curves declined gently.On the basis of this study,ABAQUS was used to analyze the influence of the axial compression ratio,grade of high strength bolts,strength grade of concrete and angle iron with stiffeners for the mechanical property of precast joint.The results of analysis on influencing factor showed that the bearing capacity of the joint increased with the increase of axial compression ratio,but the stiffness was declined.The joint damaged when the axial compression ratio is 0.9.The bearing capacity and energy-dissipating capacity of the joint increased with the increase of concrete strength grade.The bearing capacity and energy-dissipating capacity of the joint taken the angle iron with stiffeners improved significantly.And the bolts were partially damaged when the joints assembled the angle iron with two stiffeners.The bolts were no damage when the joints assembled the angle iron with one stiffeners.Because the damage was mainly concentrated on the stiffener and corner of angle steel.And the different grades of high strength bolts had no significant effect to the seismic performance of the joint.The seismic performance of the joint can be satisfied by selecting low grade bolts in the practical application of the project.The research results in this paper can provide some references for the development and application of prefabricated concrete frame structure.