The prominent office building at 55 East Monroe, overlooking Millennium Park, has undergone significant transformation, converting from an office and retail building to a luxury condominium and office and retail building in the heart of downtown, Chicago. The uppermost floors, from 42 to 49, are now condominium residences replete with ultra-luxury features. There is a full complement of indulgent amenities, and a private residential entrance with an elegant lobby at 65 East Monroe, just a few steps off Michigan Avenue.

Klein & Hoffman provided the structural services for the conversion of the top 15 floors of a 50-story building from office space to condominiums and repair of the 8-story parking garage. The scope included design of a new 10,000 square foot 49th floor slab including a swimming pool, hot tub and an outdoor terrace. The reserve capacity of the existing structure was checked to determine the feasibility of the alterations and penetrations through existing concrete shearwalls and slabs. Modifications were made when necessary to satisfy the current Chicago Building Code requirements.

Some of the challenges of this project included: The retail space beneath the parking decks and the tower above the garage were to remain open throughout the duration of the repairs; the structure was built using lightweight concrete with aggregate that were not readily available. Building code and concrete design requirement had changed necessitating upgrade to some of the structural elements. The design team stayed focused on the code and safety issues, while sensitive to the cost ramifications, by exploring various alternatives.