Fluid viscous dampers were used to retrofit a historic high-rise building in Sacramento, California. The building was constructed in the 1920's and was the first high-rise constructed in the state capital. It has 14 stories and a full basement. The building is also a state registered historic structure, and has many unique architectural features such as terra cotta tile veneer. Reinforced concrete moment frames throughout the height and reinforced concrete structural walls at the lower two floors comprise the lateral-load resisting system of this building. As part of the city's downtown revitalization, this historic structure is being transformed from an office building into a premier boutique hotel. Due to this change of occupancy, the building must now satisfy both Life Safety and Collapse Prevention performance objectives at design and ultimate earthquakes, respectively. Performance-based earthquake engineering revealed that the building would experience story drifts at its middle stories. At these levels, the concrete beams had unacceptable plastic hinge rotations. These drifts could potentially cause damage to both structural and historic non-structural components. Fluid viscous dampers were added to these critical stories to mitigate this deficiency. Additionally, steel bracing was added at the first floor to provide additional lateral and torsional stiffness and mitigate the effect of full-length reinforced concrete walls on the two back faces of the building. Analyses of the retrofitted building indicated that the performance was improved and it met its seismic performance goals.
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