Vader, Washington

BNSF 0052-0081.40 Seattle Subdivision Bridge Replacement

This project replaced Bridge 81.4, a double main track bridge over the Cowlitz River. The new structure is 12 spans, 1100-feet-long. The replacement structure was built off-line.  Both train tracks remained operational for the full project duration. A 720-foot-long work trestle was constructed; capable of withstanding the loads required to oscillate 3-meter diameter permanent casing and make tandem crane picks for DPG erection. 

This design-bid-build job changed to a CM/GC delivery method after Hamilton’s detailed evaluation of the project. Collaboration between Hamilton and BNSF produced significant time savings in change-outs and sequencing and determine the best structure and construction approach. 

​Construction innovations saved the project countless dollars and increased production. The project crew excelled in developing and implementing equipment and tools that were beneficial to project success. Cost Control included constructability reviews and detailed pricing when designs were available and at 30%, 60%, and 90% design milestones.

Permitting agencies established the environmental criteria for the project. Hamilton exceeded permitting goals by eliminating an entire work trestle on the west side of the existing bridge.

Challenges included:

• The existing structure was approximately 50 feet from OHW to the bottom chord of the bridge and was landlocked by private property on all sides. Unforeseen subsurface ground conditions differing from pre-construction borings caused difficulties during drilled shaft installation and pile driving operations. Heavy rains during winter caused unpredictable river level changes, including an event that raised the river to 100-year storm levels and created logjams on temporary and permanent bridge components within the river.   
• Hamilton collaborated with engineer partners to design a work trestle to withstand up to 8 million ft-lbs. of torque and the loads of two 250-ton cranes making 150k picks at a 60-foot radius. An extraordinary amount of longitudinal and transverse bracing was required at multiple elevation levels on the piles.
• The newly constructed bridge consisted of eight precast girder spans, each with four girders weighing over 100k, and four steel DPG spans, with full length girders weighing up to 300k.  

"Once construction began, Hamilton’s onsite staff planned and executed highly technical work safely and with a precedence on quality. Hamilton overcame construction obstacles through detailed coordination with subcontractors, ingenuity with work trestle, falsework and erection design and a qualified and competent field crew with many years of rail bridge experience.  Over the course of the project, Hamilton has been recognized by BNSF for their detailed safety planning and correlating safety records." - BNSF Project Engineer

Major Project Elements

• CM/GC
• Bridge Construction
• Innovative Construction Techniques
• Contractor Designed and Installed Temporary Work Trestle
• Close Coordination with Permitting Agencies
• Cold Weather Concreting
• Mass Concrete
• Partnering/Co-Location
• In-Water Work

Awards:

• 2023 Top Projects, Railway Track & Structures (RT&S) Award