better traction for vehicles. The work was completed in March 2012, but problems with the new deck panels began to be reported in fall 2013. Multnomah County anticipates a major seismic upgrade around 2020. The bridge was added to the National Register of Historic Places in November 2012. Description and statistics The bridge is the largest mechanical device in Oregon. gears drive 940-ton counterweights located inside each of the piers. The clearance is sufficient for most river traffic, requiring bridge openings only about 30 times a month. The bridge 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. 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, necessitating that the replacement bridge be on a different alignment. In 2005, the bridge opened for river traffic an average of 33 times a month. See also List of bridges documented by the Historic American Engineering Record in Oregon List of bridges on the National Register of Historic Places in Oregon List of crossings of the Willamette River References External links Morrison Bridge page on Multnomah County website Willamette Light Brigade Panoramic image Bascule bridges in the United States Bridges completed in 1887 Bridges completed in 1905 Bridges completed in 1958 Bridges in Portland, Oregon Bridges over the Willamette River Swing bridges in Oregon Historic American Engineering Record in Oregon National Register of Historic Places in Portland, Oregon Road bridges on the National Register of Historic Places in Oregon 1887 establishments in Oregon Buckman, Portland, Oregon Drawbridges on the National Register of Historic Places Southwest Portland, Oregon Former toll bridges in Oregon Tom McCall Waterfront Park Metal bridges in the United States