Interstate Bridge

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Interstate Bridge

Carries	Interstate 5
Crosses	Columbia River
Locale	Portland, Oregon to Vancouver, Washington
Maintained by	ODOT, WSDOT
ID number	01377, 07333
Design	Dual truss with vertical lifts
Longest span	531 feet (161.8 m)
Total length	3,538 (1078 m)
Vertical clearance	15.5 feet (4.72 m)
Clearance below	72 ft closed, 176 ft open
Opening date	February 14, 1917 (Northbound), 1958 (Southbound)
Maps and aerial photos Street map from Google Maps or Yahoo! Maps Topographic map from TopoZone Aerial image or topographic map from TerraServer-USA Satellite image from Google Maps or Microsoft Virtual Earth

The Interstate Bridge is a pair of nearly identical steel through truss bridges with a vertical lift that carries Interstate 5 traffic over the Columbia River between Vancouver, Washington and Portland, Oregon.

The bridge was built to replace an overcrowded ferry system operated by Pacific Railway, Light & Power Co. Construction on the bridge began in March 1915, following the sale of bonds.^[1] The first bridge was opened on February 14, 1917 at a cost of $1.75 million, which was shared between Clark County and Multnomah County.^[2] It was originally a toll bridge costing $.05 per person. In 1958 a $14.5 million upgrade created a southbound span and doubled the capacity of the bridge. The new bridge was built with a "humpback" that provides 72 ft of vertical clearance and minimizes bridge openings. At the time the new bridge was opened, the old one closed to give it the matching humpback. When both bridges were opened in 1960, tolls were reinstated at $.20 for cars, $.40 for light trucks, and $.60 for heavy trucks and buses, before being permanently removed in 1966.

A $3 million upgrade to the lift cables, expansion joints, and a deck repaving was completed in 1990. The diesel generator used to power the lift was replaced in 1995 at a cost of $150,000. In 1999 the bridge was repainted at a cost of $17 million. A $10.8 million electrical upgrade was completed in mid-May of 2005. ^[3]

The bridge is 3,538 ft long with a main span of 531 ft.^[4] The vertical lift provides 176 ft of clearance when opened. The lift takes 10 minutes to open and does so between 10 and 20 times per month. In 2001 the 6 lanes of the bridges carried 120,000 vehicles including 10,000 trucks, operating at capacity for four hours every day. ^[5]

[edit] Replacement

Currently, many traffic engineers consider the bridge to be obsolete, both due to its age and its limited capacity. The bridge is frequently a bottleneck which impacts both traffic on the freeway, as well as on the river. The Oregon and Washington state departments of transportation are jointly studying how to replace the bridge. The estimated cost for a replacement bridge is around $2 billion.^[6]

A replacement (especially a fixed span bridge) is complicated by a railroad drawbridge crossing the Columbia a short distance downriver, which constrains the location of the shipping channel; and by approach paths to Portland International Airport in Portland and to Pearson Field Airport in Vancouver, which limit the height of any new structure. Some have proposed replacing the bridge in a different location. There are presently 12 transportation plans that are being studied to improve and expand the Interstate 5 crossing of the Columbia River. ^[7] In late 2006, 2-4 of these plans will be selected for a final proposal. ^[8]

There is also a long standing debate as to whether or not a new bridge would include a MAX Light Rail line, express buses or bus rapid transit. During his 2007 "State of the City" address, Vancouver mayor Royce Pollard stated

“

I've said it before, but it bears repeating – Vancouver and Clark County residents have the cheapest buy-in to one of the most successful light-rail systems in the world, the MAX system. There is over $5 billion invested in light rail across the river. We can tap into that system at a very minimal cost. We’d be foolish not to. The bi-state Columbia River Crossing initiative is making plans for the future of our community for 50 years and beyond. This project should not happen without integrating light rail that comes into downtown Vancouver. If the final alternative doesn’t have a light rail component, I will not support it.^[9]

”

[edit] References

^ Holstine, Craig E. (2005). Spanning Washington : Historic highway bridges of the Evergreen State. Washington State University Press, 103-104. ISBN 0-87422-281-8.
^ Wood, Sharon (2001). The Portland Bridge Book. Oregon Historical Society. ISBN 0-87595-211-9.
^ Interstate Bridges Electrical Upgrade. Oregon Department of Transportation. Retrieved on November 5, 2006.
^ Smith, Dwight A.; Norman, James B.; Dykman, Pieter T. (1989). Historic Highway Bridges of Oregon. Oregon Historical Society Press, 209. ISBN 0-87595-205-4.
^ I-5 Partnership. "Regional Economic Effects of the I-5 Corridor: Columbia River Crossing Transportation Choke Points" (PDF). Retrieved on 2006-11-05.
^ Mayer, James. "Columbia bridge advice: Scrap the old, build new", The Oregonian, November 22, 2006.
^ Preliminary Alternative Packages. Columbia River Crossing. Retrieved on November 5, 2006.
^ Columbia River Crossing Project (2006). "Fall 2006 Newsletter" (PDF). Retrieved on 2006-11-05.
^ State of the City. City of Vancouver (January 23, 2007). Retrieved on January 25, 2007.

[edit] External links

	Bridges in the metropolitan area of Portland, Oregon See also: Transportation in Portland, Oregon
	Across the Willamette River (north to south) St. Johns Bridge - Burlington Northern Railroad Bridge 5.1 - Fremont Bridge - Broadway Bridge - Steel Bridge - Burnside Bridge - Morrison Bridge - Hawthorne Bridge - Marquam Bridge - Ross Island Bridge - Sellwood Bridge - Lake Oswego Railroad Bridge - Abernethy Bridge - Oregon City Bridge
	Across the Columbia River (west to east) Burlington Northern Railroad Bridge 9.6 - Interstate Bridge - Glenn L. Jackson Memorial Bridge