Experimental And Analytical Study Of Seismic Performance On Two-Story Double-span Prestressed Fabricated PC Frame

The development of prefabricated concrete structure is the indispensable way for the industrialization of the building. The prefabricated structure can improve the level of mechanization, speed up the construction progress, reduce labor intensity, accomplish the low-power, low-emission construction process, and achieve the requirement of the green development of the construction industry effectively. As the reliability of the fabricated structure node connection is poor, it is difficult to meet the requirement under repeated loading force. The technology of the prestressing force in this article is applied to the prestressed fabricated concrete frame by the node prestressed connection to form the overall force node and the continuous force framework, meeting the seismic requirement and making the assembly structure applied in the earthquake zone.In this article, the two-bay two-story double-span prestressed fabricated concrete frame under the pseudo-dynamic and quasi-static experiment is taken into the systematical test and researching along with the theoretical analysis. It studies a lot of seismic performances, such as the dynamic characteristics of the test framework, carrying capacity, revolving performance, section ductility and energy dissipation capacity. Numerical simulation and stress analysis are undertaken by using finite element analysis software in the test framework to provide practical methods for the applications of the prestressed fabricated concrete frame. The main content and results are as follows.The prestressed fabricated concrete frame is taken into level loading to carry out the pseudo-dynamic test, and it studies a lot of seismic performance, such as the dynamic performances, failure mechanisms, deformation properties, stiffness degradation and energy dissipation capacity of the prefabricated frame. It finally concludes the two-bay framework loading-time curve. The test results show that measured values of the framework layer yield displacement angle is between1/107and1/173, which is below1/50, namely the limit displacement angle in the elastic-plastic layer between the concrete frame in "Seismic Design of Buildings".When it is loaded to the frame yielding, the residual deformation is slight. The deformation basically recovers after unloading. In other words, there is a strong deformation recovering capabilities for the prestressed fabricated structures.The pre-fabricated frame is implemented into level loading along with the pseudo-static test. The article perceives the ductility characteristics and energy dissipation capacity of the prestressed assembly framework to get the curve of the hysteresis with the framework under the cyclic load. After the framework yields, on the beam end firstly lies the plastic hinge, and the on the column stiffness lies little degradation. The pre-fabricated frame is a "strong-pole-and-weak-beam" structure. As the prestressing tendons possess very strong deformation recovering ability, there is little residual deformation after unloading. The measured displacement ductility coefficient of the different layers in the framework is between3.67with4.44. The test framework has very good ductility. When it is loaded to the last cycle, the maximum displacement angle between the1st and the2nd layer is1/29,1/36, which can meet the requirements that an intense earthquake cannot destroy it. The frame joints under the pre-pressure and the axial compression are in the biaxial compression state, and improve the crack resistance of the core area on the nodes, which is corresponding with the requirement of the strong nodes in the seismic design.Through using fiber beam-column element in the DRAIN-2DX program, the pseudo-dynamic test framework in taken into the analytic model and the pre-fabricated frame is taken into the nonlinear time analysis. By utilizing MIDAS/Gen that can release stiffness domain of the beam end, it considers in the assembly frame beams the semi-rigid connection of the columns and the poles, and the prestressing fabricated frame is taken into the dynamic response analysis. As for the yield displacement angle between layers, the calculated values are consistent with the measured values. Analyzing the pseudo-static test framework with the Pushover, it concludes the base shear-the vertex displacement curve and the plastic hinge location along with the sequence diagram of the framework. The analyzed result is consistent with the measured position in the framework. By the ANSYS program, it simulates the static force test frame to conclude the frame column ultimate load, and the calculated value and analyzed value for the ultimate load are almost consistent.Considering the influence of the node semi-rigid in the prestressed fabricated frame, it studies the beam end section ductility and the moment modulation coefficient. It concludes the section ductility coefficient and the limitation of moment redistribution on the post-tensioned precast PC frame beam end to meet the capacity requirements, and gives the recommended formula for the moment modulation limit, as well as the moment modulation coefficient limit. Based on the experiment and theoretical analysis, it gives the basic design provision of the prestressed fabricated concrete frame, the analysis principles of the internal force and measures on seismic structure. It provides the experimental foundation and the theoretical basis for the application of making the prestressed fabricated concrete frame to promote the application of the structure system in our country.