Hybrid Tests On Seismic Performance Of Precast Concrete Frame Structure With Energy Dissipation Cladding Panel

Precast concrete exterior wall panel is a common wall panel system in the assembled structures,which is called "cladding panel" because hanging manner is often adopted to connect the panel to the main structure.A new type of precast concrete frame structure system containing energy dissipation cladding panel(EDCP)was proposed by the research team,which based on the whole-span cladding panels that are commonly used in precast concrete structures of China.The line connection,which was set avoiding the plastic hinge zones of the beam ends,was adopted on the top of the cladding panel.U-shaped steel dampers were set at the bottom of the cladding panel to form the energy dissipation connections between the main structure and the cladding panel,which a double force-bearing system was formed with the energy dissipation structure and the main structure.U-shaped steel dampers can dissipate the energy through the relative deformation between the cladding panel and the main structure under seismic actions,thus reducing the seismic response and damage of the main structure.The research team has completed the tests on the seismic performance of one-story precast shear wall structure with EDCP,which has initially verified the feasibility of the system.In order to evaluate the effect of EDCP on the seismic response of the main structure and the energy dissipation capacity under different levels of seismic action,and to further investigate the bearing capacity and damage evolution of the precast concrete frame structure with EDCP under seismic loads,the main work of this paper are as follows:(1)First,a group of U-shaped steel damper were designed,and pseudo-static tests were conducted to the dampers to study the deformation mode,bearing capacity,stiffness,energy dissipation capacity and low-cycle fatigue behavior.Based on the test results,refined and simplified finite element modeling methods based on the finite element software MSC.Marc and Opensees were proposed for the component level and structural level,respectively.The reliability of the modeling methods was verified by comparing the test results and numerical simulation results.(2)A six-story,three-span planar frame structure with EDCPs(referred to as "damping structure")and a pure frame structure as comparison(referred to as "seismic structure")were designed,which the middle span of the bottom two stories were set as the test substructures and the rest was set as the numerical substructures.The two structures were tested through hybrid tests to evaluate the effects of the EDCPs on the dynamic response and seismic performance of the precast concrete frame structure.(3)A simplified finite element model modeling method was proposed for the whole structure based on the finite element software Opensees.The connection manner between the numerical substructure and the test substructure in the model was set as an articulated connection.Rigid column units were used to simulate the cladding panels,and spring units were used to simulate U-shaped steel dampers to connect the cladding panels and the main structure.The reliability of the finite element modeling method was verified by comparing the results of the numerical simulations with the results of hybrid tests.(4)After the hybrid tests,pseudo-static tests were conducted to the test substructures to further investigate the deforming process and damage pattern of the test substructure under horizontal seismic action.The reliability of the upper line connection and the U-shaped steel plate energy dissipator at the bottom on the EDCP was observed and verified when the inter-story drift of the main structure reached the limit value of1/50 according to the Chinese code.(5)A refined finite element modeling method is proposed for the U-shaped steel damper and two test substructures based on the finite element software MSC.Marc,and results of the numerical simulation are compared with the results of pseudo-static tests and to verify the reliability of the finite element modeling method that is applicable to the component level.(6)Firstly,it was assumed that the out-of-plane load,which were generated by the gravity of the cladding panel,was all borne by the U-shaped steel dampers at the bottom of the EDCP.Then numerical simulations were conducted to the U-shaped steel damper under the out-of-plane load and bi-directional loads,separately.In order to investigate the effect of the out-of-plane loads applied to the EDCP on the energy dissipation capacity,numerical simulations were conducted to the precast concrete frame substructure with EDCPs under the out-of-plane load and bi-directional loads,separately.