Experimental Studies On Seismic Behaviors Of The Newly Energy-dissipative Prefabricated Frame Structure Joints

The shortcomings of the prefabricated frame structure, poor overall performance, andlow aseismic capacity and so on, hampers the widely application of this kind of the structurein construction. The joint was extremely easy to get damaged under the effects of earthquake.In order to avoid its―weak node‖, a new type of Energy-Dissipative prefabricated framestructure system with the sector lead viscoelastic damper was proposed, which was used forimproving the seismic performance of the prefabricated frame structure.Based on the mechanics characters of the new energy-dissipative joint above, theordinary prefabricated frame joint and newly prefabricated frame joint were designed to beanalyzed under low frequency cyclic loading. On the confirmation of the feasibility andsuperiority of this newly prefabricated frame joint, through the exploratory experimentalstudy on the condition of highly axial compression ratio, the configurations, which mayinfluence its dissipation characteristics, were made clearly. Besides that, the dissipationcharacteristics between the ordinary cast-in-situ joint and the newly cast-in-situ joint wererelatively further study. Finally, the different between this kind of joints in the aspect offailure modes and seismic performance were summarized. The main research works areshowed as below:(1)The researches about the prefabricated frame structure were summarized in nearly twodecades at home and abroad. According to the shortcomings of the study, the new type ofEnergy-Dissipative prefabricated frame structure system was put forward.(2)The preliminary mechanical analysis shows that it is effectively to protect theprefabricated frame beam-to-column joint, improve its capacity, stiffness and the energy dissipation.(3)According to the characteristic of the new type of Energy-Dissipative prefabricatedframe structure system, the two prefabricated joint including the normal and newly one weredesigned to analyze under the low frequency cyclic loading tests on the condition of0.4axialcompression ratio. Seismic behaviors such as failure modes, load-displacement curves,structural ductility, strength, stiffness degradation, energy dissipation and material strain oftwo specimens were studied. The analysis shows that hysteretic curve of the new type of theenergy-dissipative prefabricated frame structure joint with sector lead viscoelastic damper issatiated. Obviously, the performances in deformation decreases, energy dissipation, ultimatecapacity and displacement ductility are better than the normal one. Compared with the normalprefabricated structure joint, it is easier to implement the aseismic design principles, including stronger node, weak component, strong shear, weak bending.(4)After proving the better seismic performance of the new type energy-dissipativeprefabricated frame structure joint, the other four groups of modes were made to prove theeffectiveness of seismic performance of this joint under different axial compression ratio. Theanalysis shows that the higher axial compression ratio plays a role to improve theprefabricated joint‘s dissipative capability and lateral stiffness, but its ultimate bearingcapacity, stiffness and strength remain unchanged. However, its displacement ductilitydecreased significantly. The new type cast-in-situ frame structure joint and the ordinary one,which were attached with the sector lead viscoelastic damper, were designed for theexploratory experimental study. The study verified the different anti-seismic performancebetween the new type cast-in-situ frame structure joint and the ordinary one. The results showthat the stiffness, the ultimate bearing capacity and the displacement ductility of the new typecast-in-situ frame structure joint, were increased to a certain extent. Besides, the hystereticcurve appears full and smooth, and the performance of energy dissipation behaves well.Compared with the new type prefabricated frame structure joint, the hysteretic curve isrelatively long and narrow and the damper provides the stiffness as a―support‖.