Vibration control of suspension bridge due to vertical ground motions

Abstract

Suspension bridges due to their long span can experience large displacement response under dynamic loading like earthquakes. Unlike other structures, their vertical vibration may make remarkable difficulty that a control strategy seems to be essential. Tuned mass damper is a passive control system that can be changed to active one by adding an external source producing the active control force called active tuned mass damper. Unlike passive systems, active ones need a controller system affecting the performance of them considerably. In this study, the efficiency of tuned mass damper and active tuned mass damper are investigated in the bridges. Two controllers, fuzzy type 2 and fuzzy type 1, are used to estimate control force of active tuned mass damper. Tuned mass damper’s parameters are optimized under wide range of ground motions. Also, fuzzy type 2 and fuzzy type 1’s parameters are optimized under the influence of three different conditions containing far-field and near-field ground motions and also combination of them. In addition, Lion Pride Optimization Algorithm is selected for optimizing section. Numerical analysis indicates that active tuned mass damper is more effective than tuned mass damper, and also active tuned mass damper does not make any instability matter of concern in active control systems. Furthermore, performance of fuzzy type 2 is better than fuzzy type 1.