Optimization of the TMD Parameters to Suppress the Vertical Vibrations of Suspension Bridges Subjected to Earthquake Excitations

Flexible structures (such as long-span suspension bridges which undergo wind or earthquake excitations) exhibit complex dynamic behavior. Due to high cost of strengthening such structures, as well as the technological advances in recent years, much attention has been given to using innovative means of enhancing structural functionality and safety against natural hazards. Among the methods used to mitigate the excessive vibration of structures, the energy absorber systems are more promising. The present paper discusses parametric studies of the TMD system to find the optimal values of its parameters, to suppress the vertical responses of suspension bridges subjected to earthquakes’ vertical accelerations. Thomas Suspension Bridge located in Los Angles, U.S.A., is chosen as a case study, and the vertical acceleration records of 18 major worldwide earthquakes are used in numerical studies. The analysis is performed in time domain. The results of the numerical studies show that the proposed system is capable of reducing the maximum vertical displacement of the bridge to a considerably low value.