Rehabilitation projects
Rehabilitation is a major part of preservation. Rehabilitation keeps a historic bridge in active service, carrying vehicles, bicyclists, and pedestrians, while preserving Minnesota’s transportation heritage (PDF). It involves repair and upgrading of structural and mechanical components. Through periodic rehabilitation work, along with regular maintenance, a historic bridge can stay in active service for 100 years or more.
Historic bridge rehabilitation work must comply with federal requirements called the Secretary of the Interior’s Standards for the Treatment of Historic Properties—or the Secretary’s Standards. Compliance with the 10 Standards for Rehabilitation ensures that the bridge retains historic materials and appearance while meeting engineering and accessibility requirements.
Careful inspections, regular maintenance, and rehabilitation of Minnesota’s historic bridges is ongoing statewide. Below are several current and recent projects.
Planned rehabilitation
Kern Bridge (Bridge L5669)
The Kern Bridge (Bridge L5669) was located in the southeast corner of South Bend Township in Blue Earth County. In winter 2020, the bridge was removed from this site, dismantled, and stored for relocation. MnDOT then advertised the bridge as available for re-use. The bridge is now planned to be rehabilitated by the City of Mankato as a pedestrian and bicycle bridge over the Blue Earth River. Although Mankato is urban, the future Kern Bridge setting is wooded, crosses the Blue Earth River and is a similar setting to the original bridge site. Pedestrians and bicyclists will access the bridge through the existing trail system. The bridge will be seen from the north via a scenic overlook and from the south via Hwy 60/Hwy 169. The bridge is planned for rehabilitation in 2024.
Zumbro Parkway Bridge (Bridge 3219), Wabasha County
Wabasha County used funding from a Minnesota Historical & Cultural Heritage Grant (Legacy Grant) to develop rehabilitation plans for this 1937 multi-plate arch bridge that carries County Road 68 over a tributary of the Zumbro River. The project will include a complete repointing for the headwalls, railing, piers, and abutments, with replacement of deteriorated or missing stones. The concrete arch ring, formed to replicate a stone arch ring, will be repaired, along with deteriorated concrete in the piers and abutments. Fill over the arches will be excavated to apply a waterproofing coating to the multi-plate surface and the drainage system will be rehabilitated to assure proper functioning. Rusting arch surfaces will be cleaned and coated to slow corrosion.
Bridge 3589, MnDOT state bridge
The proposed rehabilitation of the 1924 (widened in 1939) Stewart River Bridge (Bridge 3589), which carries Trunk Highway 61 over the Stewart River north of Two Harbors, will involve the construction of a nearby parallel bridge to create a one-way pair. With completion of the new bridge, rehabilitation will begin on the historic bridge. The work is anticipated to include repairs to the concrete arch and wingwalls and a reconfiguration of the roadway and sidewalks, with consideration given to rehabilitation of the historic railing.
Overview photograph of Bridge 3589.
Split Rock Bridge (Bridge 5744), Eden Township
The Split Rock Bridge (Bridge 5744) is a true stone-arch structure, built by the Works Progress Administration (WPA) in 1938, carrying County Road 54 over Split Rock Creek near Ihlen in Pipestone County. Rehabilitation plans were prepared with funding from a Minnesota Historical & Cultural Heritage Grant (Legacy Grant). The roadway and fill will be removed above the stone arch and all stone masonry on the interior and exterior will be repointed. The upper surface of the arch will be protected by waterproofing before the fill is replaced. Deteriorated sections of the railings and upper wing walls will be reconstructed using replacement stones where necessary from the Jasper Quarry located four miles south of the bridge, which is the source of the original stone for the bridge. All work will comply with the Secretary of the Interior’s Standards for Rehabilitation.
Waterford Bridge (Bridge L3275), Waterford Township
Using funding from a Minnesota Historical & Cultural Heritage Grant (Legacy Grant), Waterford Township has prepared plans for the rehabilitation of Bridge L3275, a historic Camelback through truss crossing the Cannon River near Northfield in Dakota County. The planned project, designed to comply with the Secretary of the Interior’s Standards for Rehabilitation, will reconstruct elements of the concrete abutments and remove and reconstruct the concrete deck. Existing bearings will be replaced with modern bearings. Selected gusset plates will be modified with steel plates and the existing railings will be replaced with new code-compliant railings. The trusses and floor system will be blasted and repainted and the one existing historic bridge plaque will be refurbished and replicated to replace the second and missing plaque.
Spring Brook Bridge (Bridge L4646)
Using funding from a Minnesota Historical & Cultural Heritage Grant (Legacy Grant), the City of Beaver Creek, Rock County, has prepared plans for the rehabilitation of the historic Bridge L4646, constructed in 1911 to carry Sixth Street over Spring Brook. Perley N. Gillham, a local bridge builder, designed this important early reinforced-concrete bridge. The planned rehabilitation will repair all deteriorated elements of the existing concrete, including spalled surfaces, cracks, and delaminated areas. The existing gravel road surface will be removed to expose the top of the concrete arch for repair and waterproofing. All work will be completed in compliance with the Secretary of the Interior’s Standards for Rehabilitation.
Under rehabilitation
James J. Hill Stone Arch Bridge (Bridge 27004), MnDOT state bridge
Starting in April 2024, crews began repairing the James J. Hill Stone Arch Bridge (Bridge 27004) spanning the Mississippi River on the edge of downtown Minneapolis. Crews are repairing and replacing stone, replacing the mortar on the entire bridge, and making other repairs as needed. Stone repair and mortar replacement will slow deterioration and improve the condition of the bridge.
While our crews work, pedestrians and bicyclists will not be able to cross the full length of the bridge through fall 2025. Crews will close half of the bridge at a time during construction, allowing people to walk or bike to the middle of the bridge and turn around at the closure. Construction is anticipated to be complete by spring 2026.
For more project information, visit https://www.dot.state.mn.us/metro/projects/stonearchbridge/index.html.
Recently rehabilitated
In the last 20 years, Minnesota bridge owners have rehabilitated more than 40 historic bridges. Below are several recently completed examples.
Completed in 2023
Third Avenue Bridge (Bridge 2440), MnDOT state bridge
Completed in 2023, Bridge 2440 underwent required repairs to address its deteriorating condition and ensure people and goods could safely move in and out of downtown Minneapolis. Some highlighted repairs included: removal and replacement of the deck, rehabilitation of the ornamental railing panels, and repair to piers, arch ribs, and barrel arches. The railing was elevated on a concrete curb to achieve the required height standard and previous openings were narrowed to code-required dimensions using narrow bent bars. Spandrel columns were removed and replaced with new spandrel cap beams closer to the original design. The character-defining Melan arches received extensive repairs along with cathodic protection to reduce further chloride deterioration. The piers were character-defining but badly deteriorating; therefore, piers 1 and 8 were extensively reconstructed and remaining piers 2-7 were repaired. North (east bank) abutment retaining walls were partially reconstructed.
Overview photograph of Bridge 2440. Visible in this view are the three Melan-arch ribs in each span, a character-defining feature. (Trey Cambern Photography, Courtesy of HNTB).
Deck repairs during construction.
Completed in 2021
Whitewater State Park Culverts (Bridge 8592, Bridge 8593, Bridge 8594, and Bridge 8595)
These four culverts, rehabilitated in 2021, are located on a hilly, 0.3-mile segment of Trunk Highway 74 in Whitewater State Park. They were built by the WPA in 1936 and have metal, multi-plate arch barrels and limestone headwalls and flumes. The multi-plate arches needed only minor repairs, but large portions of the stone walls required reconstruction. In some badly deteriorated areas, 50 percent of the stones were replaced. Stones from two different quarries were used to create a mix of new stones that matched the color and texture of the originals. To prevent future undermining by fast-moving water, new concrete floors were installed. While the concrete was still wet, its surface was roughened by dragging it with pieces of old carpet; the texture helps the concrete visually blend with the stonework. The culverts were also protected against torrential flows with hidden concrete drop walls and large amounts of limestone riprap, most of which is buried below grade.
Bridge 8592's west headwall
This stone flume guides water into the barrel of Bridge 8593
Construction at the east end of Bridge 8594
Completed stonework at Bridge 8595
10th Avenue Bridge (Bridge 2796), City of Minneapolis
Bridge 2796 underwent rehabilitation, including replacement of the deck and reconstruction of the spandrel caps and columns, in 2019-2021. Unsympathetic railings and light standards added during a 1970s renovation were replaced by units more closely reflecting the original design. The upstream sidewalk, which was removed in the 1970s, was reinstalled and bike lanes were added to the deck.
Concrete repairs to span 5
Concrete repairs to span 4 arch rib. Deteriorated concrete was removed and replaced.
Spandrel column and arch rib concrete repairs to Span 4.
After rehab
Third Street Bridge (Bridge L5391), City of Cannon Falls
Completed in 2021, Bridge L5391 underwent repairs to address the conditions to the bridge's deck, truss structure, bearings, concrete abutments and wingwalls, and railings. Some highlighted repairs included: truss bearings were replaced with new elastomeric bearing pads, deteriorated/missing railing endposts were replaced with cast replicas, timber bridge deck was replaced with a new concrete deck, backwalls of the existing concrete abutments were replaced, bridge was repainted in a historically appropriate neutral gray, and the name and date plaques above each portal were cleaned and preserved.
Truss and railing repairs
Truss and railing repairs
Superstructure repairs
After rehab (east elevation)
Completed in 2020
Stillwater Lift Bridge (Bridge 4654)
On August 2, 2017, MnDOT redirected all vehicular traffic from the historic Stillwater Lift Bridge to the nearby new St. Croix Crossing bridge. The Stillwater Lift Bridge’s closure formally ended its 86-year-life as a major vehicular transportation crossing of the St. Croix River. The subsequent two-year rehabilitation project has converted the bridge to pedestrian and bicycle service on a new trail system. Still subject to federal navigation regulations, the lift span continues to operate on an official schedule.
The conversion project included a significant rehabilitation of all parts of the bridge, including the mechanical lift machinery and upgrades to the system’s electronics. Necessary repairs were made to the bridge tender’s house and some structural members. Railings and sidewalks were reconfigured to meet requirements of the Americans with Disabilities Act (ADA). Historic lights and the concrete balustrade were restored and the entire bridge was repainted in its original green color. A significant feature, the approach concourse on the downtown Stillwater end, was reconstructed to bring back its original surface configuration. All rehabilitation and repair work was completed in compliance with the Secretary of the Interior’s Standards for the Rehabilitation of Historic Properties.
The Lift Bridge, still in the midst of rehabilitation, shows the original green paint.
One of the bridge truss spans, Span 6, is separated from the bridge and floated off to the side to open a navigation channel while the lift span is fixed in place for repairs.
A pleasure boat sails through the navigation open channel left by the temporary removal of Span 6.
One of the two lift towers is surrounded by scaffolding while the other is shrouded in protective fabric to contain airborne materials while the steel is blasted and painted. Visible in the background is Span 6, floated out to create a navigation channel while the lift span and towers are being repaired and painted.
Downtown Stillwater viewed from the end of the lift span, high in the air.
View inside the bridge tender’s house.
Completed in 2019
Bridge 3355, MnDOT state bridge
Bridge 3355, the Whitefish Creek Bridge, carries U.S. Highway 169 over White Fish Creek, where it enters Lake Mille Lacs in Mille Lacs County. The bridge will undergo rehabilitation beginning in 2019. Historic stone masonry will be repaired and repointed, including bridge abutments, walks, and the guardrail stone wall. The bridge deck and approach lanes will be reconstructed and an integral Wyoming-type guardrail will be installed.
View following the completion.
Architectural design and treatment.
Winona Bridge (Bridge 5900), MnDOT state bridge
The 1942 Winona Bridge (Bridge 5900) completed a full rehabilitation in 2019. To accommodate increased traffic between Minnesota and Wisconsin, a second and parallel Mississippi River bridge was first built just upstream in 2016. At that point, all traffic was temporarily shifted to the new bridge and the historic bridge was closed for rehabilitation. Both bridges are now open to traffic as a one-way pair.
The three, steel, cantilevered, through-truss spans across the river—the bridge’s most significant feature—received extensive steel repairs, completed in compliance with the Secretary of the Interior’s Standards. Truss members also were retrofitted for internal redundancy as a state-required safety measure. These main spans retain all historic features and character.
The steel deck-truss approach spans on each end of the through trusses, also significant features, were removed and replaced with replica trusses using modern steel materials and construction techniques. The concrete approach spans on the south or downtown Winona side of the river were replaced with new prestressed-concrete spans in a modern design reflecting the materials and character of the original spans. At each end, the abutments of the historic and the new bridges are situated side-by-side in a complimentary arrangement, with original historic features replicated in the reconstructed abutments.
Videos of the Winona Bridge (Bridge 5900).
- Winona Bridge Inspection - June 2010 (YouTube)
Newly rehabilitated and freshly painted main cantilever truss spans await installation of new railings and roadway lights before opening to traffic.
Side-by-side view of the new 2016 Mississippi River bridge on the left and the south (downtown Winona) concrete approach spans of the rehabilitated historic bridge on the right.
The historic brick pavers, now cleaned and reinstalled beneath the reconstructed south or downtown Winona approach spans of the historic bridge.
Steelworkers complete repairs on the top chord of the main truss span, high over the Mississippi River.
The new deck trusses, in place and awaiting the pouring of the concrete deck.
Two of the replica deck trusses wait for the crane to lift them into position atop the concrete piers on the left. The new 2016 bridge is in the background, behind the crane
Boom Island Bridge (Bridge 93835)
The Boom Island Bridge (Bridge 93835) was originally built in 1901 by the Wisconsin Central Railway Company to provide rail access from Nicollet Island across the Mississippi River channel to its new railroad yard on Boom Island. The Pratt through-truss was designed by Charles F. Loweth, an important Minnesota bridge engineer. The rail yard and buildings were removed around 1970 and the area was converted into today’s park. The bridge was converted from rail to bicycle and pedestrian use.
In 2018-2019 the bridge was rehabilitated. The existing timber deck was removed and steel repairs were completed to deteriorated parts of the floor support system. A new wood plank deck was installed. When in service as a railroad bridge, there was no railing. The chain-link fence added for pedestrian use was replaced with a new metal tube and cable railing with safe narrow openings. Concrete abutments were repaired. The entire bridge was cleaned of deteriorated old paint and repainted and sealed to minimize the development of pack rust.
Removing the timber deck to repair the steel floor support system.
Completing repairs to the floor support system before installing the new plank deck. Photo courtesy of the Minneapolis Park and Recreation Board.
The new plank deck and new post and cable railing.
Boom Island Bridge following completion of the rehabilitation project.