The Chicago Athletic Association (CAA) is a building where history and engineering collide. After many started and failed attempts to re-use this historic building, the current ownership of the CAA is successfully converting it into one of the most coveted hotel keys on Michigan Avenue.

The highlights of the project included: renovation of the sub-basement, re-creation of historic canopies, modification of archaic floor systems, strengthening of faming elements, stiffening of lateral systems, augmentation of foundation systems, and cantilevering a new rooftop amenity. 

In order to capitalize on the location of the 12 S. Michigan views, developers challenged the engineering team to find a way to reasonably support a new vertical addition. The solution was a new double cantilevered system that is supported by a limited number of interior columns strategically strengthened while eliminating any new loads to the perimeter of the building where settlement is already the greatest. 

In order to accomplish these goals, the historic fabric of limited historic columns was strengthening, localized foundation strengthened, and new framing added. Four different lateral and gravity analysis modes were created to capture the boundary conditions and best predict the future movement of the building for the next 100+ years. 

Throughout the course of both design and construction, the team performed an iterative process of discovery, adaptation, and modernization of the structural system while dealing with one of the harshest winters in recent memory. The result is a building that celebrates the past and leverages opportunity to provide a new landmark for a city full of creative expression.