Experimental Study And Theoretical Analysis Of Staggered Truss Framing System With Friction Dampers

Staggered truss framing system, characterized by economy, efficiency and practicality, has drawn wide attention in both engineering and academic circles of home and abroad in recent years. However, the ductility and energy dissipation of the staggered truss framing system is poor, restricting its application in the seismic regions. Staggered truss framing system with friction dampers can be obtained by installing the friction dampers in the diagonal web members of the staggered truss framing system. Through the friction dampers absorbing and dissipating seismic energy, the entire structure is shielded from destruction, and in consequence the seismic performance of the staggered truss framing system improves remarkably.In order to study the performance of the staggered truss framing system with friction dampers, and compared with the staggered truss framing system without friction dampers, a truss was taken out from each kind of structure system. Simulating the boundary conditions of the trusses in the overall structure, experiments under cyclic load were carried out. According to the experimental data, hysteretic curves and skeleton curves of two trusses were gained, and then the ductility, stiffness, strength of two trusses was further analyzed. The experimental results show that: The ordinary truss under the horizontal load has large stiffness, but finally it is destroyed because of the fracture of the diagonal web members induced by repeated buckling. So the ductility and energy dissipation of the ordinary truss is bad. The stiffness of the truss with friction dampers is similar to that of the ordinary truss before friction dampers slip. After friction dampers slip the stiffness of the truss with friction dampers declines, then internal force of the truss redistributes. The axial force of the diagonal web members has little change, and the load increment is mainly beard by vertical web members, chords and columns. Compared with the ordinary truss, the ductility and energy dissipation of the truss with friction dampers improves remarkably in the case of the bearing capacity having no decrease.Then pushover analysis for the two trusses by using SAP2000 was carried out to get the appearance order of plastic hinge and load– displacement relationship curve under the monotonous load. After the analysis results was verified by experiment, pushover analysis for staggered truss framing system without friction dampers and staggered truss framing system with friction dampers was proceeded to compare the failure mode and the seismic performance. The analysis results show that: The stiffness and the bearing capacity of the staggered truss framing system without friction dampers decrease rapidly after the destruction of the web members at two-story and three-story, and its ductility is bad; The destruction of the staggered truss framing system with friction dampers is avoided or suspended, accordingly the seismic performance of the staggered truss framing system with friction is far superior to that of the staggered truss framing system without friction.