Sustainability Commendation – Mill Creek Bridge, Astoria, Oregon
Ever Increasing Rehabilitation needs for corroded steel bridges are one of the Oregon Department of Transportation’s (ODOT) biggest ongoing concerns.
While high-performance steel (HPS) is an important step in increasing toughness and corrosion resistance when compared to weathering steel, it is still vulnerable in corrosive and high humidity environments inherent to the state’s coastal areas. The conventional way to accommodate steel bridge corrosion is to apply protective paint coatings and to periodically recoat the bridge during its service life. However, the lifecycle cost of this design choice can be much higher than the initial cost of the steel bridge. An alternative to weathering steel or RPS and painted steel girders is corrosion-resistant ASTM A1010 Grade 50 steel that needs no corrosion protection coating.
A sample steel plate girder bridge employing A1010 is the 123ft long, 42ft, 8in wide Mill Creek Bridge along Lower Columbia River Hwy. No 2W (U.S. 30), only the second A1010 plate girder bridge for public use in the world. The pre-purchasing contract adopted for the project divided it into two segments: contracting steel fabrication as soon as the steel design and specification was completed followed by the remainder of construction. This type contract gives the fabricator extra time for ordering steel plate, testing plate samples for compliances to the contract requirements and replacing plate that does not meet them, and helps prevent time loss from unforeseen issues that could cause delays.
Owner and Designer
Oregon Department of Transportation, Salem
Contractor
Oregon State Bridge Construction, Inc., Aumsville, Ore.
Steel Fabricator
Thompson Metal Fab, Inc., Vancouver, Wash.
Detailer
DBM Vircon Services Ltd., New Westminster, B.C., Canada
First published in Modern Steel Construction
AMERICA’S BEST STEEL BRIDGES have been honored in this year’s Prize Bridge Awards competition. Conducted every two years by the National Steel Bridge Alliance (NSBA), the program honors outstanding and innovative steel bridges constructed in the U.S. The awards are presented in several categories: major span, long span, medium span, short span merit award, movable bridge, reconstructed, technological advancement, integrated project delivery, special purpose, accelerated bridge construction and sustainability. This year’s 16 winners, divided into Prize and Merit winners, include a first-of-its-kind tub girder solution in Ohio, a remote crossing in the frigid far north of Alaska and a modest double counterweight design in a coastal Maine town. Winning bridge projects were selected based on innovation, aesthetics and design and engineering solutions by a jury of five bridge professionals.
This year’s competition included a variety of bridge structure types and construction methods. All structures were required to have opened to traffic between May 1, 2014 and September 30, 2016.
