The University of Michigan Stadium, the largest college-owned football stadium in the United States, seats 107,501. The recent repair of approximately 20% of the stadium's capacity was intended to replace deteriorating seating. The repair was completed by Spence Brothers, Saginaw, Mich., at the end of July.
Because of the locker room below the stadium, load restraints required limited access, so heavy equipment, such as a crane for lifting and moving gang forms, was not feasible for this phase. To counter this problem, the forms were designed to be light enough to position by hand. Denver-based Gates & Sons designed forms with wheels that allowed the forms to be moved easily by only three workers. Concrete footing ribbons were placed ahead of time in line with the risers, and as each section was placed and stripped, the forms could be raised easily and then moved along the footing and lowered into place for the next concrete placement.
The stadium design dictated that the forms be versatile enough to form the parabolic curvature of the stadium “bowl“ shape, but cost meant that the number of different gang forms had to be minimized. As the seating rows progressed from the field to the upper level, the parabolic shape meant that height of the seating riser progressively grew. With only two sets of forms desired, each consisting of six individual gangs and covering approximately 800 square feet (42 feet wide x 19 feet deep) of concrete step surface, extra form faces were required to accommodate the placement of the forms at different angles and to adjust for the taller form height. By removing and replacing form faces, Spence Brothers was able to get by with only two main sets of forms rather than five unique sets, resulting in a significant cost savings.
The contractor also was required to tie the new stadium risers into the existing concrete risers. Because the forms were shipped to the jobsite ready to set, minimal hand setting was required to tie the new work into the existing concrete. With the exception of changing riser form faces during the concrete placement sequences, the gang forms minimized the need for time-consuming and costly labor on the job.
- Owner: The University of Michigan
- Architect/Engineer: Walker Parking Consultants
- Contractor: Spence Brothers
- Form Manufacturer: Gates & Sons, Inc. (Denver)
- Distributor: Concrete Central (Grand Rapids, Mich.)