Developer/Owner

CA Ventures

Architect

SCB

Contractor

Adjustable Forms, Inc. (concrete contractor)

Location

Chicago, IL

Background

This 26-story, 320,000 SF new residential tower is currently under construction on a 19,568 SF parcel in the South Loop of Chicago. The development is a mixed-use project that includes student housing and retail and features 320 apartments, 151 parking spaces, and about 10,000 SF of ground level retail space.

Client Benefits

Not only did BASE propose changes that would result in a cost savings of over $250,000, but the existing structural plans were thoroughly reviewed, and suggestions were provided to improve slab performance by altering support lengths, addressing potential issues in constructability, pointing out areas lacking coordination, such as the absence of mechanical openings, and recommending the extension of some tendons for required slab precompression. 

The Science and Design of Structural Engineering

BASE performed a comparative analysis and value engineering study of the typical parking and residential floors. BASE proposed several ways to simplify the post-tensioning (PT), such as by reducing the number of full length tendons and providing additional dead-end tendons only where required by analysis. It was also determined that tendons were not being used as efficiently as possible at cantilever slabs, and by increasing the tendon elevations at cantilevers, overall PT could be reduced with improved slab deflections. Together, these changes resulted in more than 20% material savings in PT alone and improved slab performance.