| This paper proposes a prefabricated concrete beam-column joint with the bolt connection.And the seismic performance of the proposed joint is investigated in depth.Specifically,the study includes the full-scale experiments and the finite element simulations.First,the full-scale experiments were conducted on the beam-column joints connected by grade 5.6 and grade 8.8 bolts,respectively,to study the impact of the bolt strength on the seismic performance of the proposed joint.Then the finite element simulations were made by the software Abaqus,based on which the results from the experiments and the simulations were compared.And the impacts of the bolt strength and the axial compression ratio on the seismic performance of the proposed joint were further studied based on the simulations.In addition to parametric analysis,this paper also optimized and improved the experimental nodes based on finite element simulation.The prefabricated joint with the bolt connection in this paper has an excellent performance in resisting seismic loading,good assembly efficiency and post-disaster repair rate,and can provide a reference for the development and application of a new type of prefabricated beam-column joint.At the same time,under the action of repeated low-axis loads,the hysteresis curves of the two groups of experimental nodes have an obvious "pinching" phenomenon.This phenomenon is the relative slippage between the bolt and the bolt hole,which also makes The energy consumption capacity of the two sets of node components has not been fully utilized.The specific work content and conclusions are as follows:(1)The two groups of experimental joint members are in beam end bending failure mode.The precast concrete semi-rigid beam-column joint is connected based on eight bolts.Simultaneously,the concrete column has a corbel,which can be used to overlap T-shaped concrete beams.The existence of bright corbels solves the problems of bolt joint installation accuracy and assembly efficiency,and at the same time,avoids the extra cost of temporary support.(2)Full-scale experiments were carried out on precast concrete semi-rigid beam-column joints connected by grade 5.6 bolts and 8.8 bolts.The experimental results show that grade 8.8 bolts have the higher ultimate bearing capacity,deformation capacity,and faster stiffness.Degradation rate,among which the ultimate bearing capacity of beam-column nodes connected by grade 8.8 bolts is increased by 17%based on beam-column nodes connected by grade 5.6 bolts.(3)This paper uses the finite element software ABAQUS to numerically simulate the joint members with different bolt strengths and different axial compression ratios based on the full-scale experimental research.It compares and analyzes the seismic performance of the simulation results.The simulation results show that bolt strength,the yield bearing capacity,and the ultimate bearing capacity of the 8.8-level bolted joint is 8% and 18% higher than that of the 5.6-level bolted joint.The initial stiffness and energy consumption performance of the nodes connected by 8.8 grade bolts are slightly higher than that of the nodes connected by 5.6 grade bolts.In terms of the axial compression ratio,the joints’ bearing capacity decreases faster and faster with the increase of the axial compression ratio.The joints’ initial stiffness increases with the increase of the axial compression ratio,and the joints’ energy consumption performance increases with the axial compression ratio.The increase is getting worse and worse.(4)Since the upper part of the beam end flange of the two groups of experimental nodes has a certain degree of concrete shear failure,because of this situation,based on finite element simulation,angle steel is added to the upper part of the beam flange to reduce The plastic strain of the concrete effect is small,and the energy dissipation performance of the joint is also improved.At the same time,the bolt stress distribution state of the improved node is more ideal.This change in the form of the node can improve the node’s repair efficiency to a certain extent.Figure [91] table [12] reference [74]... |
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