SR 99 - Spokane Street Overcrossing - Complete March 2014

We built a new 470 foot long bridge on SR 99 where it crosses over Spokane Street in Seattle. The new bridge is constructed of lightweight Geofoam blocks capped with concrete.
The new bridge replaced a timber bridge that was built in 1959. The timber supports of the old bridge were rotting and splitting apart.


How you benefit

Improves safety

Seismic standards
The new bridge is designed to meet current seismic standards to better withstand earthquake activity.

Reduced fire risk
Removing the old timber supports eliminates the threat of the wooden beams catching fire.

Traffic safety
A new barrier was installed between eastbound and westbound traffic

Protects environment
We removed timber that was coated in creosote. This reduces the risk of contaminates entering stormwater drains and pollutants from being released into the air in the event of a fire.


2005 Gas Tax (TPA):  $691,000
Pre-Existing Funds (PEF): $9,993,000
Total: $10,684,000


Contact us
Northwest Region communications
15700 Dayton Avenue North
Seattle, WA 98133

A map showing the location of the SR 99 Spokane Street overcrossing in Seattle
View larger map

A view of the old SR 99 timber bridge where it crosses over SR 99 in Seattle.
The SR 99 Spokane Street overcrossing bridge was built in 1959, using timber that eventually rotted and began splitting.

This photo shows the lightweight Geofoam blocks that were stacked and capped with concrete to build the new SR 99 Spokane Street overcrossing.
Lightweight Geofoam blocks are stacked and then capped with concrete to build the new SR 99 bridge over Spokane Street in Seattle.

See more photos of the old and new bridges.