The Challenge
A hospital expansion engineered and built while the existing facility stayed fully operational
The Loreen Lee expansion added 85,000 square feet and 120 beds to a fully operational hospital in Minneapolis that could not close for a single day during construction. Structural tie-ins to an occupied healthcare facility carry risks that don't exist on an empty site: vibration near imaging equipment, temporary load changes near connections already in service, and the constant presence of patients and staff in adjacent spaces. The facility had imaging suites and an active ICU within the construction zone boundary, both with strict vibration thresholds. Missing any of those thresholds would have meant shutting down critical services, which was not an option.
Our approach
We selected structural systems specifically for their vibration profile, avoiding methods that generate high-frequency impact where the floor plan demanded quiet. Every structural tie-in to the existing building was scheduled in a controlled window coordinated with the hospital's facilities team, with pre-notification to clinical staff before any work that could produce vibration. We instrumented sensitive areas and monitored in real time during the highest-impact operations, with pre-set thresholds that would trigger an immediate work stoppage if approached. The sequencing plan was reviewed and signed off by the facilities team before construction began, so there were no surprises for staff managing patient care.
The outcome
The hospital remained fully operational throughout the entire construction period, with no service interruptions and no days closed. The imaging suites and ICU stayed in continuous operation, and real-time monitoring showed vibration levels within threshold throughout every structural operation. The expansion added 120 beds and 85,000 square feet to the campus without the facility losing a single day of patient care. The project has since been referenced as a model for how to approach active healthcare construction in Johnson's public sector practice.
0
Days closed
120
Beds added
85,000
sf added
"We couldn't close for a single day, and we never did. They engineered around a working hospital like they'd done it a hundred times."
Jennifer Walsh, VP Facilities, Loreen Lee Health System
