Christopoulos et al. 2008
The authors examine buckling-restrained and self-centering bracing systems. In this paper, new PT-SCED braced frame technology is described, then, results from quasi-cyclic and dynamic seismic testing are conducted to verify the behavior of the proposed system. The purpose of this system is to eliminate damage to structural elements and minimize residual deformations by means of a brace member which can undergo large axial deformations.
System Concept
The structure in the study consisted of two structural steel members, pre-tensioned tendons and an energy dissipative mechanism. The fuses used were a buckling restrained and a self-centering brace. Energy dissipation is provided by friction and the members achieve a flag shaped hysteretic response. Square steel tubes were selected for the structural members due to their high compressive strength. A smaller tube is inserted into a larger one to form a compact bracing member. The fuse element can be replaced after yielding due to a bolted connection to the frame.
Experimental Study, Results and Discussion
Nonlinear dynamic analyses of building structures from 2 to 12 stories were performed to evaluate the performance of an SCED braced frames with friction energy dissipation. Cyclic quasi-static and dynamic tests with simple shear beam to column connections show similar peak inter-story drifts in SCED and BRB braced frames, but less damage concentration and smaller residual lateral deformation occurs in the SCED system. Moreover, it was observed that the residual roof displacement at the roof for BRB frame is more than SCED frame.
Analytical Study
In an analytical study, an SCED braced frame system was evaluated and compared with a frame with BRBs using nonlinear time-history analysis of typical office buildings with different story heights. The SCED system exhibits uniform distribution of the deformation demand along the building height, together with lower residual deformations than the frame with BRBs.
Reference
Christopoulos, C., Tremblay R., Erochko J., and Choi, H. (2008). “Response of 2-D and 3-D Buildings Incorporating Buckling- Restrained and Self-Centering Bracing Systems,” Canadian Society for Civil Engineering Annual Conference, Quebec City, Quebec, Canada, June 10-13.