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Analytical and Experimental Investigation of a Controlled Rocking Approach for Seismic Protection of Bridge Steel Truss Piers.
Pollino, M.; Bruneau, M.
Multidisciplinary Center for Earthquake Engineering Research, Buffalo, NY.; Federal Highway Administration, Washington, DC., January 21, 2008, 488 p.
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This reports presents the results of an analytical and experimental study on a seismic design (or retrofit) strategy that allows uplift and rocking of steel truss piers on their foundation. Displacement-based steel yielding devices and velocity-dependant viscous dampers, installed at the uplifting location, were used to control system response. The behavior of 2- and 4-legged bridge steel truss piers was considered. Methods to predict their response under multiple components of seismic excitation were evaluated using nonlinear, inelastic time history analyses. The analytical investigation included ground motions typical of far-field rock sites and near-field ground motions with pulse-type characteristics. Also, the response of 4-legged piers that resist transverse and longitudinal demands in bridges was investigated with three components of ground motion. Experimental investigations included shake table testing of a rocking pier with the added devices to verify the analytical methods and further investigate the dynamic response. Response quantities of interest include pier displacements, impact velocity, and maximum developed forces.
Dynamic response; Ground motion; Trusses; Earthquake engineering; Seismic design; Testing; Foundations; Bridge piers; Bridge steel truss piers; Forces (Loads); Excitation; Rocking approach; Structural analysis; Retrofitting