Building a Seismic-Ready Bridge – Part 2: Foundations and Cable Dampers

The bridge’s seismic resiliency begins with its foundation. More than 350 concrete piles, some reaching more than 17 stories underground, support the new bridge. These piles are custom designed to absorb much of the earthquakes’ initial energy waves.

Sitting on top of these piles are two massive towers that support the main span and more than 100 columns that support the approaches. These steel-reinforced concrete towers and columns are built to enable maximum flexibility while maintaining the structure’s strength and shape during a major earthquake.

Attached to the two towers are 80 cables that support the center portion of the bridge deck. Specially designed dampers are located where each cable is anchored to the main span, creating a state-of-the-art system that will suppress vibrations in the cables, while maintaining a high-level of flexibility during a large earthquake.

Diaphragms built inside the towers at the road deck level will help disperse seismic energy to avoid major structural impacts.

In the next edition of our seismic series, we’ll dive into one of the most intriguing areas of the bridge project – where the east and west approaches connect to the main span of the bridge.