Mortenson Construction completed a state-of-the-art medical facility for Chicago CK Enterprises, LLC, for the Michigan Avenue Radiation Center and the CyberKnife Cancer Institute of Chicago in the first two floors of a 26-story condominium building.
The cancer center, a program of Swedish Covenant Hospital, will be housed in the 10,000-square-foot facility, which posed significant construction challenges presented by its special equipment requirements and its location.
The medical facility required installation of vaults that weigh 2.5 million pounds to contain radiation equipment. That weight requires a reinforced foundation, which would typically be handled by building caissons and setting a mat slab foundation on top of the caissons. But in this building, that approach would have been costly, time-consuming, and still not allow for enough headroom.
Instead, Mortenson developed the innovative approach of inserting two foundations within the building’s existing foundation. The construction team first cut a rectangle out of the current slab, then dug down five feet to the landfill upon which the building rests. The team then installed grade beams and laid a 12-inch mat slab on top, creating a foundation that “floats” on top of the first foundation.
Also, the building's mechanical system maximizes space while reducing long-term operating costs. A typical ducted variable frequency drive (VFD) system with a dedicated mechanical room would have taken space needed for treatment rooms and other areas, so Mortenson and its design partners developed a variable refrigerant flow (VRF) system.
This highly efficient technology is smaller, has lower operating costs, and provides better control for occupants as each room is equipped with individual climate control units. The city of Chicago had not previously approved such a system, so Mortenson coordinated efforts to secure city approval.