Chicago, IL

Tenant Fitout, 200 E. Randolph Street


This insurance company relocated their headquarters to the Aon Center, a prominent building in Chicago’s skyline, and wanted to connect their space on the 32nd and 33rd floors with a feature stair. SGH analyzed the existing structure, designed the new stair, and detailed supplemental framing for the opening in the existing floor.

SGH designed the new architecturally exposed structural steel (AESS) switchback stair structure featuring laminated glass guardrails and handrails set into the plate stringers. Highlights of our work include the following:

  • Evaluated the existing steel trusses at the 32nd and 33rd floors to support new stair loads
  • Designed new framing around the slab opening in the 33rd floor to support the guardrails
  • Developed details for the existing structure to provide construction flexibility
  • Designed the new stair structure, including the stringers, treads, landing support, and connections to the base building
  • Analyzed the effects from stair traffic vibration and acceleration on occupant comfort

We also evaluated the existing floor structure under loading from proposed intermediate and main distribution frame rooms.

Project Summary



Completion Date
New Construction
Hydzik-Schade Associates, LTD.
Specialized Capabilities
Building Design

Key team members

Matthew Johnson
Matthew Johnson
Structural Engineering Division Head, Chicago
Connor Bruns
Connor Bruns
Senior Project Manager