The Interrelation Between the Dynamic Properties of Rockable Bridges and Excitations

Bridges with rockable footing are considered earthquake-resilient due to the ability to activate rigid-like body motions. The influence of rocking, however, strongly depends on the dynamic properties of the bridge and excitations. This study conducts shake table experiments on two models with different fixed-base fundamental frequencies. Nine excitations with different frequency contents but same peak ground accelerations are considered. It is shown that depending on the bridge and excitation selected, rocking can either lead to smaller or larger maximum response compared to the fixed-base case. In the considered cases, the stiff bridge always has a larger maximum displacement when allowed to rock.