Bridge L5391 on 3rd Street over the Cannon River
Bridge number: L5391
Year built: 1909-1910
Overall length: 184.3 feet
Overall width: 17.7 feet
Adapted from National Register of Historic Places nomination written by Dale Martin and Fred Quivik, Renewable Technologies, Inc. The Third Street Bridge was listed on the National Register of Historic Places in 1989.
The Third Street Bridge is a steel, single-span, riveted Pennsylvania through truss bridge. It carries Third Street North over the Cannon River. Its overall length is 184.3 feet and its overall width is 17.7 feet. The superstructure's upper chord consists of paired channels with continuous cover plates riveted on top and lacing underneath. The lower chord is two sets of paired angles sections connected by batten plates. The hip verticals are paired angles; the main verticals are paired laced channels. The verticals in the sub-divided panels consist of two sets of paired angles below the intersection and lacing between two sets of paired angles above. The diagonals consist of two sets of paired angles; in the sub-divided panels they are two different arrangements of paired angles. The floor consists of asphalt-surfaced concrete slabs on I-beam stringers which rest on angle lugs riveted to the webs of the plate girder floor beams. Angle-section out-riggers support the sidewalk on the west side. The floor beams are riveted, via angle sections, to the lower ends of the verticals. Portal bracing consists of an angle-section lattice between paired angle sections with curved knee braces. Sway bracing is similar, but without knee braces. Top and bottom lateral bracing is angle sections. The substructure consists of poured concrete abutments with wing walls. The railing on the west side (sidewalk) is lattice, with decorative cast iron newel posts. A spray-insulated pipe is on the east side, inside the truss work just above the road level. The movable end, with a rocker foot, is at the north end.
The Third Street Bridge is eligible for the National Register of Historic Places as a representative of a relatively unusual type of truss span, the Pennsylvania through truss. It is also historically significant for its associations with Minneapolis bridge builder, A.Y. Bayne, and the St. Paul engineering firm of Loweth and Wolff. It was constructed in 1909-1910, near the middle of Bayne's career as an independent bridge builder. The Pennsylvania truss (called a "petit truss" in turn-of-the-century texts) has the distinctive aspects of subdivided panels and polygonal upper chord. This type of truss could span a greater distance than the simpler Pratt and Warren trusses. As a bridge with riveted panel intersections, it represents the application of this technology to increasingly longer spans, replacing the previous standard of pin connections.
The City Council of Cannon Falls began consideration of a new bridge to replace the combination spans on Third Street by January 1909, when they sought an engineer's estimate for a new structure. Later that month at a special meeting, L.P. Wolff, a civil engineer in St. Paul and a partner in the firm of Loweth & Wolff, presented to the council estimates for steel spans of several lengths. The council decided to consider the estimates while seeking funding help from state and county sources. In June, the council accepted a revised estimate from Wolff for a 180-foot span and in the next month approved his plans and specifications after state engineers made minor changes.
In late July, the council opened bids from eight companies and selected A.Y. Bayne and Company. W.S. Hewett, formerly a partner of Bayne's and at that time head of the Security Bridge Company, protested the bid of Bayne since its construction bond was not endorsed unconditionally, as he claimed that bid proposal specified. The council went ahead with Bayne and settled on a final price of $9,010. In the previous week, the Goodhue County Commissioners had voted to appropriate $4,000 from county funds to the city for the bridge. Construction continued into the autumn and through the winter, with Bayne requesting delays on the abutments and metal work. The council accepted the bridge as complete, except for minor repairs on May 4, 1910.