Interstate Bridge

The Interstate Bridge (also Columbia River Interstate Bridge, I-5 Bridge, Portland-Vancouver Interstate Bridge, Vancouver-Portland Bridge) is a pair of nearly identical steel vertical-lift, Parker through-truss bridges that carry Interstate 5 traffic over the Columbia River between Vancouver, Washington and Portland, Oregon in the United States.

The present-day northbound bridge opened to traffic in 1917 as a single bridge carrying two-way traffic. A second twin bridge, which carries southbound traffic, opened in 1958. The twin bridges are each over long and carry three lanes of traffic. The bridges handle a combined 130,000 vehicles daily.

Since 2005, several proposals for replacing the bridge have been produced and debated. The bridge is considered responsible for traffic congestion of both road and river vehicles. Plans for a replacement bridge, known as the Columbia River Crossing (CRC) project, estimated to cost at least $3.4 billion, had come together by 2012 after many delays, but were very controversial, with both strong support and strong opposition. In late June 2013, the CRC project was canceled, after the Washington state legislature declined to authorize funding for the project. Construction on the bridge began in March 1915, and the structure opened on February 14, 1917 at a final cost of $1.75 million, which was shared between Clark and Multnomah counties. Clark County paid $500,000 and Multnomah County paid $1.25 million—probably proportional to population.

The first bridge has a total of 13 steel spans, with three measuring in length and the remaining ten spans each. One of the spans is the lift span for allowing river traffic under the bridge. and provides of clearance below when fully raised. It was originally a toll bridge costing 5¢ per vehicle or per horse and rider,

Electric streetcars operated across the bridge from opening day in 1917 until 1940. The bridge's deck carried dual gauge track, Streetcar service across the Interstate Bridge ended on September 3, 1940.

Second bridge and renovations

thumb|left|Interstate Bridge in 1973 as seen from the now demolished Thunderbird Hotel on the Oregon side

Plans to address congestion on the first Interstate Bridge, which carried over 30,000 vehicles per day by 1948, were drawn after World War II by highway officials in Oregon. The chief highway engineer, R. H. Baldock, proposed a second span over the Columbia River after it was determined that expanding the existing bridge was not feasible. Several sites were proposed and surveyed, but ultimately a twinned span west of the original bridge was chosen in September 1950 by Oregon and Washington. The proposed reinstatement of the toll led to a lawsuit that was heard by the Washington Supreme Court in September 1953 and decided in the states' favor.

In 1958, a $14.5 million ($ million in dollars) project created a second, almost identical span and doubled the capacity of the bridge. The new bridge was built with a "humpback" that provides of vertical clearance and minimizes bridge openings. and the new, parallel bridge opened to traffic on July 1, 1958.

At the time the new bridge was opened, the old one was temporarily closed for rebuilding to give it a matching humpback section. When both bridges were first open concurrently, on January 8, 1960, each bridge became one-way (the new bridge for southbound traffic and the old one for northbound traffic) and tolls were reinstated at $0.20 for cars, $0.40 for light trucks, and $0.60 for heavy trucks and buses. The tolls were removed in 1966 after the construction expenses were paid off.

A $3 million ($ million in dollars) 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 2005. The damaged trunnion on the northbound bridge was replaced in September 1997, requiring a full shutdown of I-5 for six days; the project was completed ahead of the original schedule, which anticipated a 21-day closure. A temporary commuter train was operated by Amtrak from Union Station in Portland and Vancouver station during peak hours. The free trains had ten round trips and drew an average of 1,335 passengers per day; the low ridership was attributed to the isolated location of Vancouver's station. The northbound bridge's trunnion was replaced in 2020 with all traffic carried on the southbound bridge, arranged into two lanes in the peak direction controlled by a zipper machine.

Vertical lift

The bridge is long with a main span of . The vertical lift provides of river clearance when fully opened. Openings last about ten minutes and occur between 20 and 30 times per month, or around 300 per year.

thumb|right|A barge passing under the raised lift spans

thumb|right|Viewed from the northeast, in Vancouver

Outside peak commuting times (6:30 a.m. to 9 a.m. and from 2:30 p.m. to 6 p.m), marine traffic is granted right of way at the bridge by federal law (33 CFR 117.869).

In 2006, the six total lanes of the bridges carried 130,000 vehicles daily.

Replacement planning

Columbia River Crossing (2005–2013)

The bridge is frequently a bottleneck which impacts both traffic on the freeway, as well as on the river. The Oregon and Washington transportation departments are jointly studying how to replace the bridge. Both spans have been rated as "functionally obsolete," with sufficiency ratings of 18.3% and 49.4% for the original and second spans, respectively. Initially, the estimated cost for a replacement bridge was around $2 billion, but that number has climbed steadily to around $3.4 billion. An independent study in 2010 estimated the full cost to be closer to $10 billion.

Design of a replacement (especially a fixed-span bridge) is complicated by the existence of a railroad drawbridge crossing the Columbia a short distance downriver (on the Burlington Northern Railroad Bridge 9.6), which constrains the location of the shipping channel; and by approach paths to Portland International Airport in Portland and to Pearson Field in Vancouver, which limit the height of any new structure. Some have proposed replacing the bridge in a different location. There were originally 12 transportation plans that were being studied to improve and expand the Interstate 5 crossing of the Columbia River. In late 2006, four of these plans were selected for a final proposal, along with a fifth no-build option. The Columbia River Crossing project's six local partner agencies selected a replacement I-5 bridge and light rail extension to Clark College as the project's Locally Preferred Alternative (LPA) in 2008.

There is also a longstanding 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

In December 2007, Oregon governor Ted Kulongoski advocated for a new bridge, publicly endorsing the Oregon Business Plan's proposal.

In 2008, as fuel prices increased and project cost estimates soared, many in the area began questioning whether the project is worth the costs. In addition, many on the Portland side of the river fear that a 12-lane highway bridge to Vancouver, which many also believe has virtually no land use restrictions, will encourage suburban sprawl and development north of the river.

alt=Work Lights on Interstate Bridge|thumb|Interstate Bridge in 2016 with additional illumination for late-night work crews.

Further concerns over the 12-lane "Columbia River Crossing" (CRC) proposal include its failure to examine critical environmental impacts, such as damage to Clark County's drinking water supply, endangered fish habitat in the Columbia, and air pollution in North Portland.

In 2008, the Environmental Protection Agency found that the Draft Environmental Impact Statement for the CRC had failed to adequately cover these issues, as well as the potential induced demand for suburban sprawl. In a letter to CRC planners, the EPA wrote that "There was no indication (in the CRC environmental impact statement) of how these vulnerable populations might be impacted by air pollution, noise, diesel construction vehicles and increased traffic", referring to minority communities in North Portland.

In June 2013, the Washington Legislature voted against further funding of the CRC.

The Joint Oregon-Washington Legislative Action Committee was formed by the Washington legislature in 2017 to study a bridge replacement, but initially had no Oregon representation for a year. The new committee was formed to prevent $140 million in federal funding allocated for the CRC from being recalled after a deadline, which was extended to 2025. In April 2019, the Washington legislature approved $17.5 million to establish a project office to conduct pre-design and planning work, which was followed by a matching contribution from the Oregon Transportation Commission in August.

A new timeline for the project, with the start of environmental review in 2020 and construction by 2025, was approved by the joint committee in late 2019. The replacement bridge's design is unspecified, with discussions about the inclusion of light rail, lane configurations, and investigating a third crossing all under consideration. Several alternative ideas have been proposed, including an immersed tube tunnel, a third bridge, and a bascule bridge favored by the U.S. Coast Guard, but have been rejected for their drawbacks and cost.

, the project was estimated to cost $5.5 billion to $7.5 billion. By January 2026, public records requests revealed the draft cost estimates had increased further to $13.6 billion. The locally preferred alternative selected in 2022 was an eight-lane bridge with a light rail guideway on the west side and several modified interchanges. The U.S. Coast Guard requested an alternative design with a drawbridge to preserve the clearance for river traffic, which would be lowered by if the locally preferred alternative was built. Construction was scheduled to begin in late 2025 or early 2026. Tolls will be implemented on the Oregon side of the existing bridge to help fund the new bridge as it is being built. In January 2026, the Coast Guard gave its approval for the replacement bridge to be an all-fixed-span bridge, without a movable section, at a lowered height of .

References

External links

WSDOT:Interstate Bridge
Interstate Bridge Replacement program: Home page of ODOT/WSDOT project to replace the Interstate Bridge