Boeing North Bridge Replacement

Client

Boeing Commercial Airplanes

Completion Date

2015

Designer

Berger ABAM

Location

Renton, Washington

Delivery Method

Negotiated

Division

Northwest

Contract Value

$11 million
Boeing North Bridge Replacement

Boeing North Bridge Replacement project replaced the 1969 bridge at the entrance of the Cedar River into Lake Washington. Boeing relies on this bridge to transport more than 40 Boeing 737 airplanes every month from the Renton assembly plant to the Renton Airport's flight line, where they undergo preparations for their inaugural flights. The scope of work encompassed the constructing a temporary bridge south of the existing one, demolishing the existing bridge, and constructing a new permanent bridge within the original footprint. These efforts were vital to ensuring uninterrupted access for airplane deliveries and maintaining production schedules.

Most project activities were executed during the in-water work windows between June 1 and August 15 each year, coinciding with the salmon spawning season. This phase involved tasks such as driving temporary bridge pilings, installing cofferdams, demolishing the existing bridge piers and approach aprons, lowering them below the planned dredge elevation, removing bulkheads, restoring channel grading, implementing channel bank armoring, and enhancing channel habitat.

The temporary bridge was supported by 24-inch diameter steel pipe piles, each measuring 90 feet in length, with four piles at each of the nine temporary piers. These piles were complemented by steel pile caps, steel plate girders, and a precast bridge deck. In contrast, the new permanent bridge took the form of a three-span structure, measuring 48 feet in width and 245 feet in length, featuring steel plate girders and a precast bridge deck, with the main span stretching over 134 feet. The intermediate piers (Piers 2 and 3) were anchored by two 6.5-foot diameter, 90-foot-long drilled shafts each, while the abutments (Piers 1 and 4) were supported by five 2-foot diameter, 100-foot-long concrete piles each. The superstructure also integrated precast concrete crossbeams, 4-foot diameter columns, LED guidance, and channel lighting.

Atkinson worked with Boeing, the Seattle Airports District office, and the Renton Airport to minimize airport impacts and comply with FAA regulations. This included scheduling work to reduce the duration and frequency of displaced landing thresholds, monitoring airport operations using special aviation radios, and clearing the runway of foreign object debris.