Broadway Bridge

Information and Findings From Oregon's Historic Bridge Inventory

Description

278-ft double-leaf Rall-type bascule main span with four fixed Pennsylvania-Petit though trusses and one Pratt though truss secondary spans. The approach spans are steel plate girders.

Designer

Ralph Modjeski, Chicago; Strobel Engineering, Chicago (Bascule Span)

Builders

Pennsylvania Steel Co., Steelton, Pennsylvania (Superstructure); Union Bridge and Construction Co., Kansas City (Substructure)

Significance

As the first bascule span in Portland, the city explored many options for its design. This exploration led to the choice of the patented Rall bascule design, thought to be the cheapest of the proposed types. The rare Rall-type bascule uses large Rall wheels that enable the bascules to roll backward and upward as they open in order to clear a wider channel. In addition to the unique main span, the bridge also features distinctive granite-faced and topped piers on concrete-filled pneumatic caissons.

Character Defining Features

Bascule mechanism, Location, Decorative railing, Piers, Structure type

Alterations

Major alterations including the replacement of the deck, sidewalks, electrical system for the bascule, and adding the Lovejoy Street approach.

Architectural Property Description

The Broadway Bridge opened to traffic in April 1913, spans the Willamette River in downtown Portland, Oregon, at River Mile 11.7, just downstream from the Steel Bridge, within the core of the central commercial district of the city. Comprised of six steel through-trusses, the center span is a 278-foot-long, double-leaf Rall bascule and the overall length of the structure is 1,613 feet. The Broadway Bridge was designed by Ralph Modjeski, with the operable, Rall span designed under patent by the Strobel Steel Construction Company of Chicago, Illinois. The steel superstructure of the bridge was built by the Pennsylvania Steel Company. Union Bridge and Construction Company built the masonry substructure. The bridge is owned and maintained by Multnomah County.

History

The Broadway Bridge, the first bascule or drawbridge to be constructed across the Willamette River in Portland, Oregon, was completed in April 1913. The bridge was designed by noted bridge engineer Ralph Modjeski with a Rall bascule designed by the Strobel Steel Construction Company of Chicago, Illinois. The Broadway Bridge is of statewide significance for its role within Portland's transportation and development history as the first trans-Willamette River bridge to be constructed on an entirely new alignment in the 20th century. Its construction was a response to the increased cross-river traffic north of the traditional downtown, as Portland's population and business center grew in the early part of the 20th century. The Broadway Bridge is additionally of national significance under Criterion C as one of the few surviving examples of the patented Rall-type bascule, an early alternative to the more popular bascule forms that dominated most movable bridge construction. One of only three Rall bridges still in operation in the United States, the Broadway Bridge is the largest Rall bascule to have ever been built and as such is a key exemplar of that technology. Nominated under the framework of the Willamette River Highway Bridges Multiple Property Document (MPD) and built within the first temporal period as defined by that document, the Broadway Bridge is of statewide significance under National Register eligibility Criterion A, Community Planning and Development and Transportation, for its association with the development of Portland and its transportation network between its construction in 1913 and the close of the period of significance for the MPD document in 1973. The Broadway Bridge is additionally of national significance under Criterion C, Engineering, as the oldest and largest example of the patented Rall-type bascule movable bridge design and technology known to exist. The period of significance under Criterion C is the date of construction, 1913. The Broadway Bridge meets all the general and the necessary specific registration requirements for listing under the MPD.

Bibliography

DeLony, Eric. Landmark American Bridges. Boston, MA: Little, Brown and Company, 1993.
Lansing, Jewell. Portland: People, Politics and Power 1851-2001. Corvallis, OR: Oregon State University Press, 2003-2005.
MacColl, E. Kimbark. The Growth of a City: Power and Politics in Portland, Oregon 1915-1950. Portland, OR: The Georgian Press, 1979.
McGaw, Judith A. Broadway Bridge, Historic American Engineering Record [HAER No. OR-22]. Prepared as part of the Willamette River Bridges Recording Project, HAER/Oregon Department of Transportation, in cooperation with Multnomah County, 1999.
Oregonian. Misc. issues as cited by date/page in text.
Oregon Journal. Misc. issues as cited by date/page in text.
Plowden, David. Bridges: The Spans of North America. New York, NY: The Viking Press, 1974.
Ritz, Richard Ellison. Architects of Oregon. Portland, OR: Lair Hill Publishing, 2002.
Smith, Dwight, James B. Norman and Pieter T. Dykman. Historic Highway Bridges of Oregon (2nd, Revised Ed.). Portland, OR: Oregon Historical Society Press, 1986.
The Conveyor. "Broadway Bridge Installation Marks Historic Milestone," November 2004.
Wood Wortman, Sharon, with Ed Wortman. The Portland Bridge Book (3rd Edition). Portland, OR: Urban Adventure Press, 2006.

Bridge Considered Historic By Survey: Yes