| Flexible steel frame with recycled concrete external wall(RCEW)is a new composite structure system,which has the advantages of simple beam-column connections,high prefabrication degree,rapid construction,repairability.Considering increasingly serious waste concrete processing problems,the recycled concrete is introduced into the new structure as the aggregate of recycled concrete external wall.From the construction feasibility and economic considerations,all have good engineering application prospects.Because the steel frame and the external wall through four external node connection,the transfer mechanism of the structure is complex and failure modes are not clear.For the design of such structures,there are no relative rules in Chinese code.Quasi static performance of RCEW structure was tested,not only has theoretical research significance,also has reference value for the engineering practice.Based on the experimental study and finite element analysis,the following several aspects of the research to RCEW structure was carried out.(1)Two one-bay,one-story,one-third scaled specimens of flexible steel frame with recycled concrete external wall and one same scaled specimen of steel frame were tested with low cyclic load.Main inspection parameters of test is with or without external wall and different form of beam-column joints.The effect on the external wall and beam-column joint stiffness to the force-transmission mechanism,the hysteretic performance,stiffness degradation,ductility and energy dissipation capacity of the RCEW structure were fully analyzed.The results show that external wall can significantly improve the whole performance of the structure,and beam-column joint stiffness has a little effect on seismic performance of structure.(2)Based on the analysis of ductility performance of RCEW structure,the value of the inter story displacement angle corresponding to seismic design criterion is proposed,it can provide basic basis for revision of the relevant specification.(3)On the basis of force-transmission mechanism of structure clear,the yield status and internal force distribution of steel column,steel beam,of beam-column connection of the structure is analyzed in detail,the test failure mode is explained from the angle of the internal force distribution.The force-transmission performance of external node and the work mechanism of the external wall and steel framework is analyzed.Finally,the distribution proportion of horizontal force in the structural system is presented.(4)Referring to Eurocode 3,stiffness and bearing capacity of semi-rigid beam-column joints is calculated by component and equivalent T-stub method.According to real size of the specimens,bending moment-corner relations of flush end-plate connection beam-column joints is calculated.(5)Nonlinear finite element analysis of RCEW structure is carried out by general finite element software ABAQUS.Finite element modeling process,semi-rigid beam-column joints simulation method,the working mechanism of structure on each load stage was introduced in detail.In the end,compared with experimental results,the results of finite element analysis are analyzed. |
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