To make room for 9,000 additional permanent seats in Ohio State University's famous horseshoe-shaped football stadium, a construction team had to lower the field area within the stadium 14 feet, eliminating the running track and replacing it with 10 tiers of seats. The work involved surrounding the playing field with a 50-foot-tall concrete wall. However, the wall won't block fans' view at the games because most of it is below ground.
Because the 79-year-old stadium rests atop an ancient riverbed with a high water table, engineers determined that installing the cutoff wall would be the most cost-effective means of lowering the field while maintaining the current water table beneath the existing stadium foundations. The entire wall was anchored in bedrock about 50 feet below the playing field. Before excavating, crews constructed slurry walls to maintain the two sides of the excavation and keep the sides of the trench from falling into the hole. The sides of the cutoff wall are earth-formed except for the top foot. Workers placed concrete for the wall by tremie.