Of the 20 bridges that span the Mississippi within the city limits, the Third Avenue Bridge is Minneapolis’ longest, and most in need of major repairs. The hundred-plus-year-old structure has had two facelifts, in 1939 and 1979, and the Minnesota Department of Transportation (MnDOT) has been working on a third since last May. The next phase of the work will close the bridge to all traffic for an estimated 22 months, beginning Jan. 4, 2021.
MnDOT Construction Engineer Tim Nelson said workers will take the bridge, in his words, “All the way down to the arches,” making it impossible to work with any traffic lanes open. He added, “There will be noise, dust and lights; unfortunately, noise will echo down the river.” After lower structural repairs are completed, the bridge deck will be rebuilt. The uneven areas beneath the bridge make it unfeasible to do any work from below.
The bridge is one of 24 selected by MnDOT for long-term preservation, and its rehab will address structural deterioration over the past 40 years. Originally called the St. Anthony Falls Bridge, construction began in 1914 and finished three years later. The bridge is distinguished by its use of large arches and open spandrels, and a “reverse S-curve” design that avoided placing the arch footings in parts of the river near the falls that have unstable foundations. The span is part of State Highway 65, and the lanes become Central Avenue when they reach the Northeast bank of the river.
At a virtual informational meeting on Nov. 12, MnDOT spokesman Dave Aeikens outlined the scope of the project and answered questions. He said the bridge will be closed to all traffic on Jan. 4, and the main detour route will be Hennepin Avenue for vehicles and the Stone Arch Bridge for cycles and pedestrians. He noted that the 10th Avenue Bridge, whose construction finish will overlap the Third Avenue Bridge’s start by a few months, is not considered a detour. There may be some single-lane closures on Main Street, and the RiverWest condos will have access throughout the project’s duration. On the west side, the sidewalk beneath the bridge will be closed, and West River Parkway will have temporary closings.
Aeikens said that besides the structural fixes, MnDOT’s aim is to preserve the bridge’s history by retaining its unique architectural elements, including the “Classical Revival” piers, the projecting pedestrian bays and the metal railings. The north side stairway to the bridge from Main Street will be rebuilt, but a proposal to add a stairway on the south side was cancelled. Aeikens said that a new stairway would have to be ADA-compliant, and the design couldn’t be made to match the existing stairway style. The bridge will get a light beige paint job, to match the existing color. Other improvements will include lighting, pedestrian barriers, and minor approach grading. There will be four vehicle lanes and pedestrian and cycle lanes.
The 1914 bid to build the bridge was $872,000. The current estimate for this latest rehab is $129 million. MnDOT expects the repairs to add 50 years to the bridge’s life.
Below: South side of Third Avenue Bridge, with railing removed. North side, with scaffolding, over the falls. After the lower structural repairs are complete, the bridge deck will be rebuilt. (Photos by Mark Peterson)