BNSF Wind River Bridge

With an expected lifespan of a century, the newly reconstructed BNSF Wind River Bridge serves as a critical connector on BNSF’s Fallbridge Subdivision, enabling the safe and reliable crossing of both freight and passenger traffic over the mouth of the Wind River in the Columbia River Gorge in Washington State.

HNTB provided design, permitting, and construction management services for the steel bridge’s reconstruction. The new bridge consists of a 260-ft-long, single-track truss span with precast double cell box beam approaches supported on concrete pier caps with drilled shaft and driven pile foundations. The project site is located in a national scenic area between State Highway 14 and the Columbia River, resulting in limited available site access for the contractor and the need for strict environmental compliance during construction.

Because the bridge carries a large amount of freight and passenger traffic, minimizing track closures remained a priority throughout the project. An accelerated bridge construction (ABC) technique, float-in/out, provided two distinct advantages to the project. First, it reduced the need for temporary work bridge piles, which were required to be installed and removed within a dedicated inwater work window. Secondly, it minimized impacts to railroad operations by limiting the time required to remove the existing span and install the new truss span on the existing bridge alignment.

Addressing the challenges associated with the float-in/out operation was one of the greatest challenges faced during the project, due to the number of associated variables. Because the truss span was erected in Portland, Ore., roughly 60 miles west of the project site, it was critical that the contractor’s plan to float the erected truss span down the Columbia River be fully vetted. To this end, BNSF and HNTB worked with the contractor to review their proposed maritime procedure and engineering and developed a plan to coordinate water levels with the Bonneville Dam to control the pool elevations during the bridge change-out.

Because the bridge is located in the Columbia River Gorge National Scenic Area, it was critical that the aesthetics of the new structure not disturb the existing view for the public. To address this concern, BNSF and HNTB worked with the applicable regulatory agencies to review proposed span types and bridge colors. The new main span used a Warren-type truss with weathering steel to closely match the feel of the existing Pratt-style truss and its weathered patina. Concrete pier caps and approach spans were also stained with a charcoal color to better blend in with the existing landscape. The team carefully selected materials to fulfill the project’s specific aesthetic requirements while also ensuring the integrity of the new bridge’s 100-year lifespan.

In addition to meeting a variety of requirements, the bridge design also needed to be adaptable. The bridge can accommodate the heavy live loads of current freight and passenger trains, and it is also robust enough to meet demands imposed by enhanced future railroad loading.

Project Team

• Steel fabricator: Fought & Company, Inc., Tigard, Ore. *AISC MEMBER* *AISC CERTIFIED*

• Steel detailer: Graphics for Steel Structures, Hicksville, N.Y. *AISC MEMBER*

• Engineer: HNTB, St. Louis

• General contractor: Hamilton Construction Company, Portland, Ore.

• Owner: BNSF Railway, Kansas City, Kan.