The two outside traffic lanes on the Broadway Bridge will close on Monday, July 3 after 9 a.m. for a six-month project that will replace four large steel wheels that help open and close the drawbridge for ships to pass.
The project will replace four original wheels and the tracks they roll on. The wheels and tracks are worn and cracked after a century of use. Each wheel is eight feet in diameter and weighs 88,000 pounds.
The two inside traffic lanes and both sidewalks will remain open at most times. Streetcar and bus service will continue during construction. Some weekend and night bridge closures will be needed.
The Broadway is a rare type of bridge called a Rall-wheel double-leaf drawbridge. It uses four large steel wheels to roll back and engage larger weights that lift its two center spans. The design is complex, but it opens faster and uses less energy than other bridges of its era. It also allows ships of any height to pass.
The Rall wheels support the entire weight of the opening spans: 2250 tons each. The wheels can only be replaced when a span is closed. To allow river traffic to pass, one span will be free to lift while the other is being repaired. Then the contractor will switch sides and work on the other lift span leaf. Replacing the wheels will take about three months for each side. Multnomah County is coordinating the repair schedule with river users. Most local vessels are low enough to pass the bridge without an opening.
The four new wheels were forged in the eastern United States and machined in Portland at Peninsula Iron Works. The tracks were machined at Vigor in Portland. Hamilton Construction of Springfield, OR is the construction manager/general contractor for the $12 million project.
Multnomah County maintains the Broadway Bridge and five other Willamette River bridges. For more information, visit www.multco.us/bridges or follow us on Twitter @MultcoBridges. For information about public agency infrastructure projects throughout the central city, visit Get Portland Moving at MovePDX.net.