Fremont Bridge (Portland, Oregon)

The Fremont Bridge is a steel tied-arch bridgeTemplate:Cn over the Willamette River located in Portland, Oregon, United States. It carries Interstate 405 and US 30 traffic between downtown and North Portland where it intersects with Interstate 5. It has the longest main span of any bridge in Oregon and is the second longest tied-arch bridge in the world (after Caiyuanba Bridge across the Yangtze River, China).<ref name = "Wood-Wortman">Template:Cite book</ref> The bridge was designed by Parsons, Brinckerhoff, Quade and Douglas, and built by Murphy Pacific Corporation.<ref name="Bottenberg">Template:Cite book</ref> In 2006, Sharon Wood Wortman published the third and latest version of The Portland Bridge Book. This book provides even more detail about the Fremont Bridge than covered here.<ref name="Wood-Wortman" />

The bridge has two decks carrying vehicular traffic, each with four lanes. The upper deck is signed westbound on US 30 and southbound on I-405. The lower deck is signed eastbound on US 30 and northbound on I-405.

File:MSH-10B Mount St. Helens Erupts, Portland View, May 18, 1980 (22636191326).jpg

Mount St. Helens erupting on May 18, 1980, with the Fremont Bridge on the left.

Design and construction

Due to the public's dissatisfaction with the appearance of the Marquam Bridge opened in 1966, the Portland Art Commission was invited to participate in the design process of the Fremont. The improvement in visual quality resulted in a bridge that was nearly six times as expensive as the purposely economical Marquam Bridge. Designers modeled the bridge after the original 1964 Port Mann Bridge in Vancouver, British Columbia.

The steel tie-girder (I-beam) is Template:Convert tall and Template:Convert wide. On October 28, 1971, while still under construction, a Template:Convert crack was found on the west span of this girder that required a $5.5 million redesign and repair. The ramps and approaches are steel box girders. If the lanes of the bridge were placed end-to-end, there are Template:Convert on the arch bridge and Template:Convert on the ramps and approaches.<ref name="Bottenberg" />

The center span of the bridge, where the rib of the arch is above the deck, is Template:Convert long.<ref name="Bottenberg" /> It was fabricated in California then assembled at Swan Island Industrial Park, Template:Convert downstream.<ref name = "Wood-Wortman" /> After assembly it was floated on a barge the Template:Convert trip to the construction site.<ref name="Bottenberg" /> On March 16, 1973, the Template:Convert steel arch span was lifted Template:Convert using 32 hydraulic jacks. At the time, it was listed in the Guinness Book of World Records as the heaviest lift ever completed.<ref>Template:Cite book</ref>

The bridge was opened on November 15, 1973,<ref name=opens>Template:Cite news</ref><ref name = "Wood-Wortman"/> at a final cost of $82 million (equivalent to $Template:Inflation million in Template:Inflation/year),<ref name = "Wood-Wortman" /> most of which was financed by the Federal Highway Administration. In 1976, an American flag and an Oregon flag were added atop the structure as part of the bicentennial celebration for the United States.<ref name=flags>Template:Cite news</ref> The flags were installed with the use of a helicopter.<ref name="Bottenberg" /> The Template:Convert flags are attached to Template:Convert tall flagpoles at the crest of the arches.<ref name=flags/>

Falcon nest

The Fremont Bridge was also the 26th Peregrine falcon nest site designated in Oregon in 1995 after the raptor was placed on the U.S. Threatened and Endangered Species list in 1970.<ref>Template:Cite web</ref>

The falcon has since been removed from the list and is now listed as least concern.<ref>Template:Cite web</ref>

Etymology

The bridge as well as Portland's associated Fremont Street were named for John C. Frémont (1813–1890), an early explorer of Las Californias and the Oregon Country. He served in the United States Army at the time as a Captain and was later promoted to General. In 1856, he ran for president, but was defeated by James Buchanan.<ref>Template:Cite book</ref>

See also

• Template:Portal-inline
• Template:Portal-inline
• Template:Portal-inline
• List of bridges documented by the Historic American Engineering Record in Oregon
• List of crossings of the Willamette River

External links

• Template:HAER
• Template:Structurae