Jerome F. Hajjar - Department of Civil and Environmental Engineering

Kassis and Tremblay 2008

Braced fuse systems for low-rise steel buildings and its design procedure were presented in this paper. Design and performance of the braced fuse system were explained in light of tests. A parametric study was also performed to show that the use of braced fuses results in cost reductions when compared to T/C braced frames.

System Concept

This system has been developed for braces made of rectangular or square structural tubing. The braced fuse systems were used to keep the braces in tension during ground motion, allowing for an increase in design forces. The fuses are located near the brace end. Rectangular or square structural tubing was used for this fuse system. The tubes were cut at the fuse locations and four angles were used to connect the two tube segments. These angles are located along each of the four corners of the tube cross section and welded to each of the two brace segments. Unfortunately, these braced tension fuse systems are not replaceable, since welded connections are used.

Experimental Study, Results, and Discussion

The results from full scale quasi static cyclic tests performed to verify the performance of the braced fuse systems for low-rise steel buildings are presented. The results of quasi-static cyclic tests verified the seismic performance of the system and the effects of brace fuse systems on force demand in low-rise steel buildings. From test results, it is concluded that adding brace fuses in T/C to moderately ductile MD braced frames is an effective way to reduce the connection tension design loads.

Parametric Study

Parametric study was performed to evaluate the benefits of using the proposed brace fuse design. Rectangular single story steel structures with different plan areas and different plan aspect ratios were used for this study. MD and LD braced steel frames with and without brace fuse systems were designed and compared. According to the results, MD designs were more effective than LD type. Moreover, adding brace fuses in T/C type MD brace frames was the best solution for reducing the connection tension design loads.

Reference

Kassis, D. and Tremblay R. (2008). “Brace Fuse System for Cost-Effective Design of Low-rise Steel Buildings,” Proceedings of the Canadian Society for Civil Engineering Annual Conference, Quebec City, Quebec, Canada, June 10-13.