Minnesota DOT Replaces Fracture-Critical Eisenhower Memorial Bridge
Rebuilding the Eisenhower Memorial Bridge: Minnesota DOT Rebuilds Critical Connection to Wisconsin with Community Input
Crews are making great headway on replacing an older bridge crossing the Mississippi River and connecting Red Wing, Minnesota, and Hagar City, Wisconsin, with a more modern and safer structure.
“The bridge that will be constructed will improve and enhance our safety, commerce and our efforts to welcome visitors to this community and the region,” says Sean Dowse, Mayor of Red Wing at the groundbreaking ceremony in May 2017.
The current 1,631-feet long, continuous steel truss bridge was called the Hiawatha Bridge and later renamed for former President Dwight D. Eisenhower, who dedicated the bridge on October 18, 1960. It was built in the river on barges and raised into place. It remains the only regional crossing for about 30 miles upstream and downstream. About 13,300 vehicles cross the bridge daily.
The Minnesota Department of Transportation (MnDOT) took seven years to plan and design the bridge, involving members of the community in determining the future structure. The department considered rehabilitation and replacement options, before choosing to rebuild the bridge. MnDOT designed the new structure, which according to Dowse, will serve the community for a century.
The new $63.4 million, 1,642-foot long Eisenhower Memorial Bridge will provide two lanes for vehicular traffic, one in each direction, and add a 12-foot-wide space for pedestrians and bikers and a bump out space to watch boats in the river. The new bridge will be 70 feet above the river, 5 feet taller than the existing bridge. In addition to the span over the Mississippi River, the bridge project includes spans over Highway 61 and Bluff Street in Red Wing. The project includes building new approach roads and some work on city streets, including storm and sanitary main work.
Funding the New Bridge
In 2007, the Interstate 35W bridge collapsed prompting the Minnesota Legislature to come up with bonding money to replace fracture-critical bridges in the state, explains Mark Anderson, Construction Project Manager for MnDOT. Fracture critical refers to a bridge in which the entire structure could fail if one section failed. The entire Eisenhower Memorial Bridge could collapse if damage occurred to its original truss design. That funding was used toward replacing this bridge in Red Wing.
The Wisconsin Department of Transportation has provided half of the funding for the bridge and for the construction of the approaches on the Wisconsin side. The Federal Highway Administration and the City of Red Wing also contributed.
Zenith Tech of Waukesha, Wisconsin, was the low bidder among four and received the construction contract to build the new bridge. Work started in May 2017 on the first of five stages of construction.
On the Wisconsin side, Zenith Tech began the project by surcharging the soil before construction could begin. It could take up to a year for the fill to settle. The company installed wick drains to direct water away from the soils. On the Minnesota side, four buildings were torn down to make room for the new bridge. Additionally, crews found foundations from old buildings buried in the bridges path. A historical team assessed each find before construction moved ahead.
The contractor built a temporary bridge over Highway 61, with wood decking covered by bituminous.
To protect the wetlands and the river, crews installed afloating silt curtain and metal sheeting and will install geotextile fabric when the temporary bridge is demolished.
Traffic continues to flow on that temporary bridge structure and on the Eisenhower Memorial Bridge. Some nighttime closures have been necessary, and some local streets closed. MnDOT has kept the public informed about changes to the traffic patterns and construction updates, including an active Facebook page. Additionally, in October, MnDOT and the Red Wing Chamber of Commerce offered public tours of the project.
The foundation includes six piers, four on pilings and two on drilled shafts. Piers 1 and 2 are on drilled shafts. Piers three through six, in Wisconsin, are complete. The north and south abutments also are complete.
Pier 1 has two 10-foot drilled shafts, and pier 2 has four 9-inch drilled shafts. Pier 2’s foundation will reach 80 feet down to bedrock.
“The reason drilled shafts were used for piers 1 and 2 was to not cause any vibrations to Barn Bluff,” Anderson explains.
Barn Bluff is a limestone formation, which appears to look like a barn and provides places people can stop and look at views of the river valley. Additionally, the bridge is near a downtown historic district and care was taken with a vibration-monitoring plan and pre-and post-construction surveys to ensure no historic properties are damaged during construction. Sixty-six buildings, including 15 historic buildings, are being monitored for vibration.
Zenith Tech is using barges to construct pier 2, in the Mississippi River. Crews drilled shafts in the river, installed four 9-foot diameter pipes as casings for the shafts, and built a cofferdam to keep the work space around the foundation dry. The company is using 86-foot-long sheet piles
Next, the company will build pier 1 on the Minnesota side. The piers are arched and although poured concrete, give the appearance of being constructed of stone.
The bridge contains 28 175-foot-long prestressed concrete beams, weighing about 200,000 pounds each. They were fabricated in Janesville, Wisconsin. These are the largest and heaviest beams the company has set.
The bridge will feature aesthetic lighting, lights on the pillars, wash lighting to outline the bridge shape from the river and shoreline, and ornamental railings. The lighting can be turned off during mayfly hatching season, when bugs can make the roadway slippery.
Zenith Tech crews are expected to work through the winter. The project remains on schedule, and MnDOT anticipates the new bridge will open to traffic in fall 2019. Once open, crews will begin dismantling piece by piece the current Eisenhower Memorial Bridge and the temporary Highway 61 bridge. The project is expected to wrap up in August 2020.
MnDOT expects the new bridge will improve traffic mobility in downtown Red Wing.
- Owner: Minnesota Department of Transportation
- Designer: Minnesota Department of Transportation
- Contractor: Zenith Tech, Waukesha, Wisconsin