Braun Intertec was retained to assist with construction of the St. Anthony Falls Heritage Center in Minneapolis, which serves as the home for the Mill City Museum and several office-level tenants.

In addition to renovation of much of the old mill and affiliated structures, a new eight-story, post-tensioned concrete structure was constructed in the middle of mill ruins.

Challenges

The existing mill was constructed with many different materials as a result of a century of additions and renovations. The result was a labyrinth of structures, rooms and floors that was confusing to navigate. Nearly 70 different structural details were required to make structural connections. The location of the details was sporadic, making the construction and inspection teams’ job of discerning what was needed and where in the labyrinth of structures extremely challenging. Approximately 8,000 adhesive anchors were embedded into the existing masonry walls with various structural properties.

Previous building evaluations and environmental site cleanup were performed, but as construction progressed, new building materials were discovered that required immediate evaluation to prevent construction delays.

Solutions

Our experienced International Code Council (ICC) Certified special inspection and testing team was able to competently decipher the complex construction plans and details and assist the contractor in determining what structural components were needed and where.

When potentially asbestos and lead-containing materials were discovered, we responded with certified personnel capable of identifying and sampling the materials. In-house laboratories provided quick and seamless material analysis, followed by prompt remediation recommendations. Various metal components of the century-old railroad shed had unknown physical properties. We quickly analyzed the materials and provided comments on their weldability and structural capacity. We observed the excavation of diving buried topsoil throughout portions of the site and that of alluvial and glacial soils used to support the building’s footings.