Midwest
John Hancock Center, Scaffold Collapse
On 9 March 2002, a 100 ft long, suspended scaffold platform fell from the 42nd floor of the John Hancock Center. SGH investigated the causes of the failure.
Chicago, IL
111 East Wacker Drive
Scope/Solutions
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
Photo courtesy of HED Design
Photo courtesy of HED Design
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Project Summary
2023
Completion Date
award
Winner
Solutions
New Construction
Services
Structures
Markets
Commercial
Client(s)
HED Design
Specialized Capabilities
Repair & Strengthening
Key team members
Additional Projects
Midwest
300 East Randolph Street
During a routine facade inspection of 300 East Randolph, the inspector identified granite panels on the fifty-seven-story tower that needed to be replaced. SGH assisted the contractor by designing anchorage for the replacement panels.