Conventional and dissipative bracing solutions for a steel gym building

Two conventional and an advanced bracing design solutions are developed for a steel gym building. A classical X-shaped configuration is selected for the first two solutions, which differ one from another for the design strategy assumed. In one case, a traditional ductility-based approach is followed, by adopting a basic behaviour factor equal to 4, reduced by 20% to take into account the structural irregularity determined by the eccentric position of the intermediate floor of the building. In the second case, a completely elastic response is pursued until the Life Safety performance level is reached and, as a consequence, with a behaviour factor fixed at 1. A dissipative bracing system incorporating pressurized fluid viscous spring-dampers is assumed as anti-seismic technology for the third solution. The performance objectives are the same as those formulated for the second conventional design hypothesis. The resulting dimensions of the members, as well as the total weight and cost of the steel structure are compared for the three solutions. A 50% net reduction of the cost and an improved look of the structure due to the remarkably greater slenderness of the constituting members; and a substantially higher seismic performance at all the normative design levels, come out for the dissipative bracing-based design as compared to the elastic, and ductile X-bracing solutions, respectively.