COMMISSION AGENDA – Briefing Item No. 7b Page 2 of 5
Meeting Date: May 12, 2020
Template revised September 22, 2016.
passage. Vehicular traffic will be exacerbated once commuters return to the roadways this
summer as the COVID-19 pandemic eases.
The WSB was originally designed for three lanes of travel in each direction. As Seattle grew, the
bridge grew to three westbound lanes and four eastbound. This added traffic, combined with the
significant increase in size and weight of commercial vehicles and transit, compounded the long-
term maintenance challenges posed to the bridge structure WSB. Further, 80 percent of the
bridge load is dead load, meaning deterioration is possible even when all traffic is removed.
In 2019, however, the Federal load rating for this type of bridge changed and the City assembled
a team of engineers and experts from the public and private sectors to begin actively assessing
the extent and growth of bridge cracking, create safety recommendations, and a short-term
repair plan. As a component of that review, the City has been regularly inspecting concrete cracks
in the high bridge. During a late March inspection, one of their engineers found known cracks in
the concrete had worsened at a rate that the City and outside specialists found unacceptable,
hence the decision to close the WSB to all traffic.
In the immediate aftermath of the bridge’s closure, Port and NWSA staff engaged with the City
and other stakeholders to ensure access to Terminal 5 (T-5) to support cargo operations and
continues to acknowledge the importance of continual freight access through the SW Spokane
Street corridor.
With respect to the NWSA-managed container terminals and freight access – the City
acknowledges the importance of the NWSA’s container terminals to the regional economy
through the “Container Port Element” of their Comprehensive Plan. More specifically, it calls for
them to: “Monitor, maintain and improve key freight corridors, networks and intermodal
connections that provide access to cargo container facilities and the industrial areas around them
to address bottlenecks and other access constraints. Provide safe, reliable, efficient and direct
access between Port marine facilities and the state highway or interstate system, and between
Port terminals and railroad intermodal facilities …”
The policy is implemented through Seattle’s Freight Master Plan, which lists the SW Spokane
Street, including the low bridge, as “Major Truck Street.” It is also part of the City’s designated
freight network, providing access to the freeway system and rail intermodal facilities in Seattle.
In addition, it is a key corridor on the City’s heavy haul network, enabling trucks with up to 98,000
gross weight to move between T-5 and the railyards and transload facilities in the surrounding
Manufacturing Industrial Center.
CURRENT STATUS
The City will be providing an overview of what led to closure of the WSB and how they have
responded to date, including ongoing emergency contingency efforts, the near-term timeline on
shoring and other engineering work and initial traffic mitigation plans.