Beneficial Bunker

St. Louis general contractor/construction manager Tarlton Corp., in partnership with Morton, Ill. concrete and masonry contractor Otto Baum Company Inc., recently completed a cast-in-place proton therapy vault for an OSF HealthCare Saint Francis Medical Center clinic in Peoria, Ill. 

With wall sections up to 25-ft. thick, the $5.5 million structure is Tarlton Concrete Division’s second such mass feat in the last five years. The Tarlton and Otto Baum team placed 4,520 yd. for the vault, which houses Varian Medical Systems equipment for noninvasive cancer treatment. Unlike many radiation-shielding structures, the OSF vault has no lead lining. Consequently, precise concrete practice was essential to delivering a finished structure capable of stopping and absorbing traveling protons. 

Doka USA Ltd. fully engineered the concrete formwork to minimize deflections and maintain vertical and horizontal tolerances. A thermal control plan, critical to the execution of the pours, was developed in conjunction with CTL Group, Illinois-based engineering, architecture and materials science consulting firm. Sensors placed throughout the concrete schedule carefully monitored and tracked temperature differentials. The team maintained the forming schedule by streamlining a blockout process for adjacent pours; it allowed crews to reduce the cure time between pours without sacrificing concrete integrity and quality.

The Tarlton and Otto Baum team, along with ready mixed supplier Roanoke Concrete Products, performed the proton therapy vault work under contract with Peoria-based PointCore Construction. The joint venture of OSF HealthCare and Core Construction launched in 2019 with an eye to design-build health care facility project delivery.