Chicago, Illinois

Ontario Street Substation

Client / Owner

ComEd (now Exelon Corporation)

Architect / Engineer

Stanley Tigerman & Associates




Graycor Industrial

Project Scope

Graycor constructed ComEd’s downtown substation building, located at Ontario and Dearborn streets, just west of Chicago’s Magnificent Mile. The postmodernist-style building, designed by Chicago architect Stanley Tigerman, measures 100-foot by 100-foot by 60-foot above-grade and 22-foot below-grade. The concrete and steel-structured distribution and transmission center houses 138-kV transmission bus equipment with four 200,000-pound transformers. Due to site constraints, just-in-time material deliveries were made throughout the project’s duration.

Scope of Project:

Site work

Underground utilities

Cast-in-place concrete structure

Interior electrical switchgear components and equipment

CO2 fire protection equipment

Exterior masonry, specialty cut stone and architectural finish work