Completed in December 1996, the $670 million South Building expansion of Chicago's McCormick Place Convention center was one of the largest develop/design/build projects in the United States. Despite the vast scope of the 2.9-million-gross-square-foot expansion, Mc3D Inc., the develop/design/build consortium assembled specifically for this project, completed the work on schedule and under budget. One of Mc3D's biggest challenges in expanding the convention center was the diversity of the concrete work: More than 200,000 cubic yards of cast-in-place concrete were required for road construction, building construction, and architectural elements.
One of the project's biggest challenge was a construction of a huge 900,000-square-foot floor slab, which required more than 150,000 cubic yards of concrete. The 21-inch-thick slab was set in two layers: a 12-inch-thick structural layer followed by a 9-inch-thick topping slab that encases utility ducts and ports.