The dynamic intelligent bridge: A new concept in bridge dynamics

A method is put forward for designing bridges with improved performance under extreme dynamic loadings, such as strong earthquakes. The basic idea is that varying the boundary conditions can lead to an improved structural performance under dynamic actions. The specific goal is to substitute current bridge joints that have a fixed width with variable-width joints, which initially can be either closed or open depending on their length and the serviceability requirements, while under seismic loading their width is optimised either with a one-off adjustment, or continuously varying through semi-active control. In all cases, a novel device is used that permits this improved behaviour of the joints, the moveable shear key (MSK), a device for blocking the movement of the bridge deck, which is not permanently fixed to the seat of the abutment but can slide, hence opening a previously closed gap or closing an existing gap between the deck and the abutment. The performance sought by varying the joint gap depends on the design objectives. A pilot study on the effect of gap size is also presented, which illustrates that it can significantly affect the response quantities of the abutments.