Transportation
Route 14 Interchange Reconstruction
*Reconstruction of a congested diamond interchange carrying 62,000 vehicles per day, including two new bridges, a single-point ramp configuration and 2.4 miles of widened mainline, built under CM/GC with all lanes open at peak.
- Client
- Cascadia Regional DOT
- Engineer
- Meridian Transportation Partners
- Location
- Camas, WA
- Value
- $25M–$100M
- Delivery
- CM/GC
- Status
- Completed
- Completed
- 2022
Spec sheet
By the numbers
- Bridges
- 2 structures, 318 ft and 244 ft
- Mainline widening
- 2.4 lane-miles each direction
- MSE retaining walls
- 41,000 SF
- Asphalt placed
- 86,000 tons
- Concrete placed
- 12,300 CY
- Contract value
- $61.8 million (GMP)
Story
Challenge, solution and outcome
Challenge
The interchange handled 62,000 vehicles a day with a weaving movement that backed up onto the mainline every weekday afternoon. The owner would not accept lane closures between 6 a.m. and 9 p.m. and capped nighttime full-ramp closures at 30 nights for the project.
Utilities in the corridor included a 24-inch water main, two transmission-voltage poles and a 14-inch gas line that crossed the proposed ramp alignment.
Solution
As CM/GC we joined the design team at 30 percent, and our preconstruction team re-sequenced the project into five traffic stages that reduced required ramp closures from 30 nights to 19. Value engineering of the east bridge from steel to precast prestressed girders saved $2.1 million and six weeks of fabrication lead time.
We moved utilities before each stage with the utility owners at the table, carried four weeks of schedule float in the baseline and used movable barrier for the reversible lane through the work zone. Concrete paving of the ramps was completed in two weekend closures.
Outcome
The interchange opened to its final configuration 63 days ahead of schedule and $3.4 million below the guaranteed maximum price, with savings returned to the owner. Average afternoon delay through the corridor fell from 14 minutes to under 3 minutes.
No lane closure violated the owner's restrictions, and the project recorded 0 lost-time incidents over 412,000 hours worked.
Safety
Safety highlights
- 0 lost-time incidents over 412,000 work hours
- Movable barrier and queue-warning system with zero work-zone intrusions
- Night-work lighting plan reviewed by an independent safety consultant
- Weekly traffic control audits by ATSSA-certified supervisors
From the owner
“The CM/GC process worked as advertised. Their estimators found schedule and cost in our design that we would not have found until bid, and the corridor stayed moving the entire time.”
Gallery
Project gallery
