Optima Old Orchard Woods

Skokie, Illinois

A mixed-use residential and commercial development, Old Orchard Woods links together three 20-story towers. The 700 condominiums have floor-to-ceiling windows with views of the surrounding city. Residential bridges and one below-grade level connect the buildings, while the first three stories create one continuous façade housing commercial space and common areas.

The reinforced concrete towers were originally planned as three separate phases separated by expansion joints. Lateral analysis revealed the potential for too much relative movement of the long perpendicular floor plates across the joints. CSA worked with the architect to create multi-level residential links which tie the towers together to move as one under wind loading. These residential links are supported by columns unbraced for as many as 6 stories. The lateral system required design for the temporary conditions of each separate phase working independently and also for the combined system of the linked towers. Detailed finite element analysis of the highly stressed slab diaphragms was required for the links to withstand the forces necessary for tying the three towers together. Innovative structural design allowed for the complex architectural configurations to be achieved while maintaining the light, open architectural intent with cost-effective details.

Size: 1.6 Million SF
Stories: 20
Architect: Optima, Inc.
Developer: Optima, Inc.