Experimental Study On Stiffness And Ductility Of Composite Steel Staggered Truss Structures

The steel staggered truss system is a new concept in structure steel framing for high-rise buildings,and it is characterized by practicability,economy and efficiency. To promote such a system in our country,this paper was studied on the composite steel staggered truss structures under cyclic loading.According to the Steel Design Guide Series 14:Staggered Truss Framing Systems of American and Chinese relevant codes,one-third scaled specimen of five story composite staggered truss structure was designed,including the design of global structure,joint design and the detail drawing.For the development of a pilot program, papers carried out the elastic-plastic analysis of monotonic loading by finite element program ANSYS,and provided the bearing capacity,deformation patterns and stress-strain distribution in different loading history.Then according to the results of the finite element analysis,the experimental scheme of specimen was developed,including loading history,test position displacement and layout of stain gauge.The circulating test was carried out on the model.Based on the test results,the P-⊿ hysteretic curve,the P-⊿ skeleton curve and the limit supporting capacity were found, also degradation of structural stiffness,the ductility and performance of plastic deformation,the energy consumption ability and failure mechanism were analyzed.The following conclusions would be suggested in terms of test results:The P-⊿ skeleton curve of composite staggered truss structure appeared steady and plump without obvious pinching;The bearing capacity of the composite staggered truss structures was high,but the stiffness deteriorate faster;the first story is structural weak story;the ductility and plastic deformation ability were not very good,and it could be improved; The failure mode of the composite staggered truss structure belonged to beam(truss) plastic hinge mechanism.