Abstract
Optimization of passive energy dissipation devices, such as isolator bearings, to improve seismic performance of elevated bridges is studied. At the first half of the paper, general optimization procedure for seismic response reduction is constructed through approximating the seismic excitation by stationary Gaussian white noise. Following the construction of this general method, optimal design of deck connections and bearings is investigated in details using simple linear two-degree-of-freedom structural models. Analytical expressions for optimal design values are also developed for these devices. The validity of the proposed optimization procedure and design values is demonstrated using the observed ground motions of 1940 El Centro earthquake, and 1995 Kobe earthquake measured at the JMA Kobe Station. Characteristics of seismic response of these controlled structures and limitation of performance improvement by energy dissipation devices are also discussed.
