The Optima Chicago Center & Optima Signature are two high-rise towers offering luxury apartments in downtown Chicago. Floor-to-ceiling glass windows overlook expansive city and lakefront views. Building amenities include a fitness center, residents’ club, indoor basketball court, indoor & outdoor swimming pools and sky garden terrace.
The first tower (Optima Chicago Center) is an efficient, 455-foot tall, 42-story concrete structure with flat-plate, post-tensioned slabs and shear walls around the elevator/stair core. After the success of the first tower, the developer/architect wished to build a second (Optima Signature) with the same layout, plus 15 more stories, adding 146 feet to the building height. The innovative design included an outrigger system at the level 20 mechanical floor and at the top of the building, while maintaining a simple layout on all other floors. The intermittent outriggers made the lateral system work for this 57-story, 601-foot tall tower with only a 21-foot deep core. The interference of existing caissons posed the challenge of transferring out the entire core at the foundations. With our insight and expertise, we were able to use the elevator pit walls as part of the transfer system, minimizing the depth of the excavation required.
Size: 541,000 SF & 871,000 SF
Stories: 42 & 57
Architect: Optima, Inc.
Developer: Optima, Inc.