Seattle SR-520 Floating Bridge
How geometry-led metamaterials reduced expansion joint noise on live highway infrastructure.
Impact noise at the expansion joint.
Vehicles crossing expansion joints on the SR-520 bridge generate significant impact noise. The bridge structure must remain continuous while allowing thermal expansion and contraction — meaning conventional structural modifications that add mass or stiffness are not an option.
Disrupting the noise transmission path.
A metamaterial concept was designed and deployed at the expansion joint. The noise transmission path was disrupted without compromising the structural movement of the bridge. This demonstrates non-invasive solutions that respect existing structural constraints — geometry working within the joint, not against it.
First deployment on live infrastructure.
First deployment of geometry-led noise control on live civil infrastructure. Validated disruption of impact noise at the source — non-invasive, scalable geometry.