A study on earthquake protection of steel buildings by buckling restrained braces and viscous dampers

Earthquakes can cause so many injuries and unfortunately kill thousands of people. Structures must be designed so as to resist this insidious natural phenomenon by means of seismic protection. This study evaluates the seismic behavior of steel frames upgraded with buckling restrained braces (BRBs) and viscous dampers (VDs) in different configurations. The structural models used were three different frame systems of 4, 8 and 12 stories. All of the frames were designed with equal span length of 6.5 m and storey height of 4 m. The BRBs and VDs were placed over the height of each frame considering three different configurations, namely the outer-bays, inner-bays, and all-bays. The structures were modeled using SAP2000 finite element program and examined by means of the nonlinear time history analysis subjected to the six natural earthquake records (1976 Gazli, 1978 Tabas, 1987 Superstition Hills, 1992 Cape Mendocino, 1994 Northridge and 1999 Chi-Chi). The seismic response of the structures with and without BRBs or VDs were studied in terms of variation in the displacement, interstorey drift, absolute acceleration, maximum base shear, maximum base moment, time history of roof displacement. The analysis of the results indicated that BRBs and VDs had provided considerable, enhancement in the earthquake performance of the key study steel frames by diminishing both the local and global deformations.