Project Highlights

• Preservation of original 1912 building’s historic character
• Complex site along the Mississippi River cut into vertical rock
• Large areas of modification to support new equipment

Overview

Repowering of the University of Minnesota’s Old Main Power Plant involved removing seven coal and natural gas boilers, dating back to the mid-1920s, and replacing them with an 18-25 megawatt co-generation power plant, all while preserving as much of the building’s historic character as possible. Structurally, the 39,600 square foot building consists of the four exterior brick walls, a modified roof with clerestory, a concrete operations area, a basement slab-on-grade, and a concrete operating level. It is cut into the Mississippi river bluff, with the north wall poured against the vertical rock cut and the footings and slab-on-grade bearing on the horizontal rock shelf. The structural task included evaluating the existing structural strength and condition, and making significant modifications to support the new equipment. This included removing and replacing large sections of the plant, creating new load paths through the existing structure, and adding new structural systems to respond to the new uses. Because the building’s structural columns were integrated into the structure of the boilers, some of the columns needed to be removed and replaced. The latest point-cloud methods were used to record the current building configuration, and building information modeling (BIM) was used to coordinate the structural, architectural, and mechanical designs.