I-84 Twin Bridges replacement contract apparent low bid announced,
The two-year project to replace two Interstate 84 bridges spanning the Snake River will begin later this spring, the Idaho Transportation Department announced.
The construction will replace both I-84 bridges crossing the Snake River as well as reconstruct the westbound on-ramp and eastbound off-ramp at the Declo Interchange (Exit 216). The new bridges will be slightly longer, wider, include fewer piers in the water, and increase vertical clearance for river traffic.
The project is expected to begin in late spring with preliminary work and construction of a temporary ramp before demolition and construction of the westbound bridge. A temporary loop ramp will be installed for westbound traffic entering at the Declo Interchange and all other ramps will remain open.
Throughout construction, traffic on I-84 will be reduced to a single lane in each direction as all traffic will be diverted onto a single bridge. A speed restriction of 50 mph will be in effect for the duration of the project due to the narrow lanes and high traffic numbers. Detours will also be in effect for all wide and heavy loads.
The existing structures, constructed in 1960 as part of the original interstate construction, are both considered structurally deficient. Each bridge carries about 7,000 vehicles per day.