Seismic Dampers Protect the Towers & Main Span

Among the high-tech features of the new bridge are the tower dampers that would keep the main span road deck from knocking into the towers in both directions (north-south and east-west) during a seismic event. While it may appear that the main span is attached directly to the towers, it is not. It is suspended from the towers, connected via the 80 cable stays, and only directly attached to the approach structures.

There is one set of dampers in each direction. The photo above shows construction crews installing the longitudinal damper bracket to the tower, and connecting the dampers to the bracket. The giant pistons will absorb the movement of the road deck during a seismic event and prevent the road deck from banging into the giant towers and causing damage.

These dampers are installed on and below the road deck (see below) and are just one of several seismic features to protect the new bridge elements during an earthquake to help ensure the roadway remains open.