Duluth Armory floor replacement to begin

The structural capacity of the concrete slab, which has an entire level of parking and storage below, has been compromised by decades of water and salts seeping into the floor and rusting the rebar during the 1980s and 1990s when the Armory was used as a garage for heavy equipment.

The Armory Arts and Music Center (AAMC) organization announced the beginning of its Drill Hall floor stabilization project. The $1.5 million-dollar investment will fund reinforcement of 4,000 square feet of the existing concrete floor and removal and replacement of 14,000 square feet of the floor. 

The Drill Hall floor stabilization is the last major hurdle that remains to lift the demolition order that was placed on the historic Armory in 2000, developers said. 

“Over the years, we’ve been addressing the items listed on the demo order, including patching the roof, tuck-pointing brick and terra cotta, fixing windows and general cleanup. The floor is the last major item to be addressed,” noted AAMC Executive Director Mark Poirier.

The structural capacity of the concrete slab, which has an entire level of parking and storage below, has been compromised by decades of water and salts seeping into the floor and rusting the rebar during the 1980s and 1990s when the Armory was used as a garage for heavy equipment. The rusting rebar over the concrete columns expanded, forcing the concrete topping to rise over the columns, giving the floor an uneven appearance. Eventually, wood timbers were installed under the floor to support the slab to allow the heavy equipment to continue to park on the floor.

Gardner Builders is leading the floor stabilization project work beginning this month, with plans to be complete by the end of January. During the bidding process, Gardner found ways to do the work and will bring in a specialty demolition contractor from Chicago that utilizes robots and special concrete-cutting equipment.

LHB did the structural design work, which uncovered that the original structural engineer for the Armory was Claude Turner, who is the same structural engineer who designed Duluth’s Aerial Lift Bridge. Turner, a pioneering engineer based in St. Paul, designed some of the earliest flat concrete floor slabs of which the Armory’s Drill Hall is one example. He had patents for his floor slab designs. Unfortunately, the math and engineering methodology that Turner used in 1915 did not evolve into what is accepted today by building codes. That and the compromised condition of the steel rebar at a number of locations led to the decision to replace much of the floor. 

Charlene Roise of Hess Roise provided historical consulting expertise for the project. Having a historical consultant aboard was important because the Armory is listed on the National Register of Historic Places. A portion of the funding has been provided from a $250,000 Legacy Grant from the Minnesota Historical Society, and additional funding is from State and Federal Historic Tax Credits, all of which have special application processes and reporting requirements. The remainder of the funding has been provided by several private donors.

The program for the full redevelopment is building momentum toward a mixed-use commercial project centered on creating a public market/food hall while retaining the historic stage with community space in front for events and exhibits. The size of the building would allow other uses and users also, and would showcase the views of Lake Superior from the four-story "Head House" section of the building facing London Road. The AAMC is currently working with UMD’s Center for Economic Development on the business plan and city of Duluth staff have shared their in-house expertise on public markets.

“We feel the Armory would be a great location for a public market that features locally made food and products from local entrepreneurs. The Armory has a wonderful location near the Rose Garden, Lake Walk and other shopping, and will be an attractive destination for both locals and people from out of town,” noted AAMC Vice President Mike Poupore.