Ambient Vibration Control of Suspended Bridges Using Self-Centering Friction Damping Brace

Abstract

This research presents methods to control vibration of suspended bridges decks by incorporating a self-centering friction damping mechanism to (1) mitigate damaging ambient vibrations and (2) maintain a necessary potential of energy dissipation during major seismic excitation. To achieve this, a thorough investigation of the relationship between viscous and friction damping is conducted both analytically and in a numerical computer model. The objective of this paper is to introduce friction damping concepts as well as methods of approaching equivalent viscous damping. Necessary design parameters for friction dampers will be identified and compared to that of their viscous damping counterpart in an effort achieve equal energy dissipation. Furthermore, this paper introduces the modified self-centering friction damping brace (SFDB) and discusses the concept of design and analysis for replacement of viscous dampers in suspended bridges. The modified SFDB is analyzed in a single degree of freedom system and compared to a typical viscously damped system. The free vibration behavior of the modified SFDB is compared to viscous damping behavior and evaluated for future research involving the retrofit of the Vincent Thomas Bridge in San Pedro, CA.