Passive Vibration Control of Curved Bridges using Multiple Tuned Mass Dampers Subjected to Bidirectional Ground Motions

Purpose The susceptibility of horizontally curved bridges (HCBs) to deck unseating during strong earthquakes is well-known due to their decks' large displacements. Compared to straight bridges (STBs) that have a regular geometry, the curved shape of HCBs makes their dynamic behavior complicated and less predictable, leading to a higher probability of failure. Methods In this paper, an analytical approach is developed to investigate the application of multiple tuned mass dampers (MTMDs) for passive control of the planar rigid body motion of HCB decks supported on elastomeric rubber bearings (ERBs) under bi-directional ground motions. For this purpose, a dynamic model with 3 + 2nd degrees-of-freedom (DOFs) is proposed to describe the planar rigid body motion of deck with nd pairs of TMDs acting in two orthogonal directions along the radial and azimuthal axes. This model is validated by comparison with the results of time history analysis of finite element model of a typical HCB. To evaluate the effectiveness and robustness of MTMDs system, an extensive parametric study is carried out on the key parameters of the sample HCB including the number and frequency, damping, and mass ratios of MTMDs, the flexibility of ERBs, and the curvature and shape of deck. Results and Conclusions The numerical results demonstrate that the proposed passive control strategy is effective in controlling the planar rigid body motion of HCB decks under bi-directional ground motion. Increasing the number of TMDs (nd > 5) and distributing them symmetrically around the symmetry axis of the deck results in better performance, even for the same total mass.