A temporary replacement span for the I-5 highway bridge that collapsed last week could be in place relatively soon, according to a plan released by Washington State Governor Jay Inslee over the Memorial Day holiday weekend.
“We will install a temporary span on the bridge that will restore traffic while we build a safe and durable permanent span adjacent to it,” the Governor noted in a statement, adding that if the remaining inspections of the bridge structure find no additional damage, the temporary bridge could be in place within weeks.
The state’s department of transportation (WSDOT) added that it’s completed an examination of the still-standing southern section of the I-5 bridge spanning the Skagit River near Mt. Vernon, WA, and determined it will not need to be replaced.
However, Gov. Inslee stressed that once debris from the collapsed northern portion of the I-5 bridge structure is fully removed, further underwater structural examinations will be necessary to determine if additional repairs are needed before installing the temporary span.
WSDOT pointed out that the temporary four-lane bridge span – consisting of two, 24-foot wide structures that will be pre-built and trucked to the site to allow for accelerated installation – will only carry I-5 traffic over the Skagit River at a reduced speed and capacity.
That could pose something of a problem as the I-5 corridor carries 71,000 vehicles each day and is the only north-south interstate in Washington state, noted WSDOT Transportation Secretary Lynn Peterson, who emphasized that although the short-term fix will bring some relief to drivers and the community, the final resolution is still months away.
“We ask for everyone’s patience as we transition from emergency operations to long-term repair,” said Secretary Peterson, noting that the reduced speeds on the “interim” bridge means traffic backups will continue to be a challenge, both locally and on I-5.
“Drivers should still allow extra time when traveling through the area [and] detours will remain in place to provide drivers with travel options,” Peterson said. ““The home stretch will be a two week total closure of I-5 likely in September as crews remove the temporary structure and move the permanent bridge into place.”
WSDOT added that federal funding should make up 90% of the cost of a permanent replacement bridge, with the initial estimate for said span costing around $15 million.