As part of the reconstruction of the elevated State/Lake CTA station, GSG performed geotechnical and subsurface utility engineering (SUE) services to support phased demolition and construction in a congested urban environment.

Scope of Services

• • Coordinated with CTA, CDOT, and OUC for site access and permits
  • Reviewed Phase I study and developed a sampling plan
  • Conducted GPR survey and SUE Level A investigation at 13 locations
  • Completed 13 hydrovac potholes and utility clearance
  • Advanced 9 deep soil borings (121–133 ft), including bedrock coring
  • Logged SPT results, soil samples, and groundwater depth
  • Collected 10 pavement cores for section analysis
  • Provided engineering analysis for deep foundation (drilled shaft and micropiles) for the platform and elevators
  • Performed lab testing and prepared a geotechnical report with construction recommendations