Project of the Year: Parking Structures Category
Grant Park South Garage Rehabilitation
Submitted by Walker Parking Consultants
Chicago Park District
Walker Parking Consultants
The Grant Park South Garage is an underground parking facility originally constructed in 1963, and located in downtown Chicago, Illinois. The four-level facility includes three underground parking levels. The top or fourth level supports portions of Grant Park, Michigan Avenue, and Jackson Street. The structure includes 536,000 square feet (49,800 square meter) and 1300 parking spaces, with high parking demand that fills the spaces several times per day.
The rehabilitation provided long-term solutions to correct structural deterioration, provide operational enhancements, and modernize other aging systems in the garage. The primary concrete repairs included full-depth slab replacement for the garage and Michigan Avenue concrete slabs. The slab replacements included calcium nitrate corrosion inhibitor and moisture protection systems. Concrete repairs were provided at the lower level garage slab that is also the primary garage foundation mat. Partial depth concrete repairs were used to minimize difficulties in keeping the existing parks and street operations in place during the entire construction project. Hydrodemolition was used to remove the top 3 inches (7.6 cm) of concrete and provide a new concrete environment (microsilica and calcium nitrate) around all foundation slab top bars. Pedestrian stairways also required repair and reconstruction of the concrete stair support structures.
Cost control for the new structural, electrical, architectural, mechanical and preventative maintenance requirements included life cycle cost analysis and service life evaluations. The construction manager and design team developed the phasing to allow the roadway construction and garage construction to alternate – thereby keeping the construction crews to a uniform large size. This approach reduced remobilization costs and kept the construction moving at an accelerated pace.
The rehabilitation provided a cost effective solution and extended the service life by more than 25 years. The improvements enhanced operations and updated the garage for new building codes and laws. The garage will be able to continue operations with minimal operational or maintenance costs and generate revenues for Park District programs.