Located on the University of Minnesota campus, Pillsbury Hall was built in 1889 making it the second oldest building on campus and easily the most iconic. In the early days, Pillsbury Hall was home to animal biology, botany, geology, mineralogy, and paleontology complete with lecture, recitation, laboratory, and museum rooms. Until 2017, Pillsbury Hall was home to the Department of Geology and Geophysics and the Limnological Research Center. With this renovation, Pillsbury Hall serves as a 21st century home for the Department of English, its Creative Writing Program, and the Liberal Arts Engagement Hub.

JE Dunn started with substantial structural modifications to the existing building including increasing load capacity of the existing wood floors by adding sister joists to existing joists, modifying structure to eliminate existing columns for new floor plan, creating new structural openings in the floor for new stair, elevator and mechanical shafts, creating new structural openings in the 3’ thick interior masonry walls for new overhead MEP, and creating a new basement at the west side of the building to house MEP equipment.

To create the basement, the JE Dunn and Carl Bolander team drilled a set of piles at each interior column location with equipment on the existing first floor slab, thru the slab, and down ~ 20 feet to below the new pad elevation. After piles were set, structurally engineered scaffolding was erected at each interior footing/column location from the top of the piles up to the bottom of the existing 2nd floor so the existing building could be properly supported. Once complete, the existing first floor slab was removed so equipment could be brought into the building to lower the basement.

During excavation for the new basement, it was discovered that the existing building footings comprised stacked stone, and not a continuous concrete footing. This required a creative solution of applying shotcrete on both sides of the existing foundation and then installing 3 thru bolts every 4’ to “sandwich” the existing foundation so conventional underpinning work could be completed.

In addition to the extensive structural modifications, the project scope also included a new underground connection to the Gopher Way tunnel system, modified egress solutions (ADA building entries, fully sprinklered building, stairwell, elevator modernization, etc.), new HVAC systems (chilled beam system), and new finishes throughout the building.

The project was constructed during the Covid-19 pandemic and experienced various schedule, phasing, and staffing challenges in order to complete the project on time. The building is also listed on the U of M campus historic area registry requiring the JE Dunn and design team to meet SHPO requirements for any exterior improvements. One unique solution was the use of an existing building chimney for HVAC ductwork in lieu of installing new exterior louvers.

The JE Dunn team worked closely with several consultants and specialists including Architecture Advantage, BKBM Engineers, AET, Engineering Partners, and IMEG to complete this exceptional building renovation. The use of virtual design modeling assisted with construction activities and helped the team understand the extensive structural modification work.