| Morrison Bridge | |
|---|---|
| Carries | motor vehicles, pedestrians, cyclists |
| Crosses | Willamette River |
| Locale | Portland, Oregon |
| Maintained by | Multnomah County |
| ID number | 02758 |
| Design | double-leaf "Chicago style" bascule |
| Total length | 760 feet (236.1 m) |
| Width | 90 feet (27.4 m) |
| Longest span | 284 feet |
| Clearance below | 69 feet closed |
| Opened | May 24, 1958 (Replaced 1887 and 1905 bridges) |
The Morrison Bridge is a bascule bridge that spans the Willamette River in Portland, Oregon.
The original Morrison Bridge was a wooden truss swing span bridge completed on April 12, 1887 as the first Willamette River bridge in Portland and the longest bridge west of the Mississippi River. It was first a toll bridge (rates: horse drawn rig - US$0.15, team of horses - $0.20, pedestrian - $0.05) but went toll free in 1895.[1] The second Morrison was another swing bridge that was built in 1905. It was not designed for automobiles and the 1958 replacement was long overdue.
The present bridge was built by Multnomah County. It was completed on May 24, 1958 at a cost of $12.9 million. In 1961, Interstate 5 and Interstate 84 ramps were added. In 2011, the steel grating on the bascule deck was scheduled to be replaced with fiber-reinforced polymer panels to provide better traction for vehicles.[2] However, due to environmental issues with the contractor, the work will not be completed until 2012. Access for bicycles and pedestrians is being improved in a $1.9 million project which began construction in March 2009.[3] Multnomah County estimates a major seismic upgrade around 2020.
The bridge is the largest mechanical device in Oregon.[4] 36 ft. tall gears drive 940-ton counterweights located inside each of the piers. The 69 ft. clearance is sufficient for most river traffic, requiring bridge openings only about 30 times a month. It currently carries 50,000 vehicles daily in six lanes. The canted windows of the control tower give the distinctive look of air traffic control towers. It is named after John L. Morrison, a Scottish immigrant who built the first home on Morrison Street. The current bridge does not connect to Morrison Street at its west end because the second bridge was left in operation while the latest version was built.
In 1987 the Morrison Bridge became the first bridge illuminated by the Willamette Light Brigade. In 2007 the original 16 colored floodlamps illuminating the concrete piers were replaced by energy efficient and computer controlled LEDs.[5] Millions of colors may be selected for each of eight zones of the piers.[6] Static and animated patterns may be requested for a fee which ranges from $100 per night to $1200 per month.[7][8]
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