Pekcan, Mander, and Chen 2002
The authors investigated tension only brace configurations for steel deck-truss bridges with dampers and sacrificial fuse bars. A one third scale model is tested on a shake table with various configurations.
System Concept
Tendon elements provide diagonal bracing for steel deck-truss bridges when the bridge is deformed laterally. This can often result in excessive residual drifts after seismic events. Spring dampers or fuse bars are intended to provide a restoring force so that the deck can self-center after a load is applied. The fuse bars are intended to dissipate energy by yielding and deforming inelastically. The goal in mind is to reduce the force that is transmitted to the piers by dissipating some of the energy through the deformation of the fuse bars.
Experimental Study, Results and Discussion
Tests were performed on a shake table for ten pre-stressed tendon only structures, ten pre-stressed tendons with dampers, and twenty-seven structures with pre-stressed tendons, dampers, and sacrificial fuse bars. The size of the fuse bars was a variable of interest, and had a strong correlation with the magnitude of measured deck displacement, base shear, and bearing shear. Pre-stressing levels were also varied.
It was found that the most desirable configuration included dampers with sacrificial fuse bars. The fuse bars effectively dissipate energy and reduce the magnitude of the forces transmitted to the piers. This is an especially positive result since the fuse bars are easily replaceable after they sustain damage, and thus limit the time that a bridge with this system would need to be closed after an event.
Reference
Pekcan, G., Mander, J. B., and Chen, S. S. (2002). "Seismic Retrofit of Steel Deck-Truss Bridges: Experimental Investigation," Advances in Structural Engineering 5.3.173.