Experiment On Stiffness And Ductility Of Reformed Type Of Composite Staggered Truss Steel Structures

Steel staggered truss system has a good performance under earthquake, but its application is very rare in our country due to the lack of research on the seismic performance. As part of study sponsored by Ministry of Science and Technology "Development of Application Technology of Staggered Truss System", model test is carried out to study the hysteretic behavior in this paper. This is the first time in our country, so the study has great significance in theory and in practice.One-third scale specimen of five story composite staggered truss structures was designed by ETABS in this paper according to similar theory and relevant codes, and ultimate internal force considering wind load combinition, earthquake load combination and the utmost load combination was analysed, which offered the basis for joint design.This paper carried out the design on global structure, floor and gave the detail of darwing. Then pushover analysis was proceeded by finite element program ETABS to find out the structural mode, the stress-strain distribution, carrying capacity, and the formation and expansion of plastic hinge.According to the results of finite element analysis by ETABS, the experimental scheme of specimen is established which include loading history and layout of stain gauge, and so on. According to the test result, the hysteresis curve and the skeleton curve of the reformed composite stagggerd trusses system were obtained, and the bearing capacity, stiffness and ductility were analyzed. As a result, the following conlusions may be suggested: the bearing capacity of the reformed composite stagggerd trusses system is large, but is destroyed after reaching the maximum, it deteriortate quickly after the maximum reached; The distribution of stiffnees became rational, the weakness storey was transferred to second floor; the ductility of structure of system remains to be improving further; the hysteresis curve of structure of system appeared shuttle shape, without obvious phenomenon of contracting, guaranted the structure system's dissipation energy ability.The above-mentioned conclusions can lay a good foundation and provide important basis for further research.