Case Study
114. Tempering Tremors: San Bernardino Courthouse
Application of Taylor Devices dampers in a steel frame structure building.
Application of Taylor Devices dampers in a steel frame structure building.
From a Space Program Hall of Fame induction to one of the tallest, mixed-use buildings in San Francisco, Taylor Devices continues to provide the most efficient, effective and innovative structural protection products on the planet.
In this paper, three kinds of supplemental energy dissipation devices are investigated to upgrade the seismic performance of the case study building, including fluid viscous dampers, viscous wall dampers, and buckling restrained braces.
This paper discusses model, design, and application of viscous dampers in one the skyscraper in New York City.
The two frame office towers, constructed in the 1970s per the 1967 edition of the UBC, use perimeter reinforced concrete moment frames to resist seismic loading. The buildings are rectangular in plan and have certain characteristics that adversely affect their seismic performance, in particular the presence of a soft-story response at the first floor (approximately 50% taller than typical floors), and limited ductility typical of buildings of that era. Risk analysis showed that for the towers the PML exceeded 20%. Nonlinear response history analysis (NLRHA) of the towers was conducted and showed that in the existing configuration, the story drift ratios (SDRs) at the first floor exceeded 2%, shear hinging of the first floor beams was expected and that the SDRs would need to be reduced to approximately 1.4% for the first floor to limit the extent of nonlinear response. Seismic retrofit included addition of 300-kip viscous dampers in both directions to the first floor of the building.
This paper provides a case study of a five story commercial building, where supplemental fluid viscous dampers are combined with a steel moment frame structure to provide a dual seismic resisting system. The paper outlines the analysis and design procedure.
This paper will outline the specifics in quantifying the continued damper performance through an intermediate inspection after seven years, followed by a successful comprehensive inspection after eleven years. This included the removal, dynamic testing, and re-installation of three selected dampers.
Soft weak open front (SWOF) buildings often perform poorly in earthquakes. Two examples are buildings with a street facing garage, or commercial facilities with extensive open display windows. The poor performance of SWOF structures can consist of complete loss of use or even total collapse. This paper presents an approach to protecting such structures via the addition of an energy dissipation system (viscous dampers) such that peak inter-story drifts are limited to about 1% under relatively severe seismic events, thus keeping the deformations within the elastic range. With this addition of damping, earthquake survivability of this class of structures increases significantly. A series of seismic analyses are presented herein to demonstrate the potential performance of the damping system. In addition, a variety of damper installation configurations that provide enhanced energy dissipation are discussed.