Chicago, IL

111 East Wacker Drive


A law firm occupying two floors of 111 East Wacker Drive was expanding their offices to the floor below. As part of the fitout design for the new space, the firm wanted to modify an existing circular stair connecting the upper two levels and add a new stair structure to extend the existing stair down to the level below. SGH provided structural engineering services for the stair and associated modifications to the existing building.

SGH served as the structural engineer of record for modifications to the existing stair, the new stair structure, and portions of the 1960s building supporting the stair. Highlights of our work include:

  • Evaluating the existing circular stair for new wood cladding and glass guards
  • Designing a new circular steel stair structure
  • Performing a vibration analysis and designing the new and existing stair structures to satisfy recommended guidelines in AISC 360 and Design Guide #11
  • Evaluating the effects of the new stair and floor opening on the reinforced concrete building structure
  • Designing supplemental steel framing for the existing concrete waffle slab floor system to transfer existing stair loads to the base building

Project Summary



Completion Date
New Construction
HED Design
Specialized Capabilities
Repair & Strengthening

Key team members