When the Charlotte Coliseum was completed in 1988, it took two years and $52 million to build. Back then it was the largest venue in the NBA with a seating capacity over 24,000. Frank Sinatra opened the facility with a concert in August 1988, and later such acts as the Rolling Stones, Bruce Springsteen and Celine Dion would play there. The coliseum was the home of the NBA's Charlotte Hornets and later the Charlotte Bobcats, as well as the WNBA's Charlotte Sting and two arena football teams. The coliseum's final act was to serve as an emergency shelter for victims of Hurricane Katrina.
It took 15 seconds to bring it all down.
In reality, preparing the coliseum for demolition began several months ago. The effort included an auction of collectibles and useable items from the facility including seats and the basketball court, which raised funds for youth sports activities in Charlotte. Other items were donated to local sports organizations.
Crews then began gutting the building during the first phase of demolition. CST Environmental, which has handled the pre-implosion demolition and post-implosion recycling of materials from the building, began by demolishing the 22,000-square-foot elliptical arena floor and the seating area. They also removed the rear service concourse and the exterior masonry brick. Because the building was constructed in the 1980s using modern construction materials and techniques, there was only a limited amount of hazardous material. All of this material was collected and safely removed from the site for proper handling.
In April, CST and Dykon Blasting Corp. began the second phase of the demolition process by preparing the building for the implosion. The coliseum's foundations were built on drilled caissons with an average depth of 60 feet. The building was approximately 495,000 square feet in size with a vertical height of 125 feet from the arena floor to the top of the spatial roof, which had spans approximately 375 feet long.
The structure of the coliseum has made its demolition rather unique. The coliseum lacked expansion joints in the roof system. In fact, the coliseum had one of the largest single-span roof systems at approximately 250,000 square feet. The roof was supported around the perimeter by A-frame columns that were designed to pivot to allow movement. These A-frames were located in the plane of the exterior wall and were designed to carry all of the lateral loads experienced by the structure. No longer needed to support the coliseum, the spatial truss system helped bring the coliseum down once the shape charges cut through the beams.
Engineers from Dykon Blasting created detailed plans for the placement of 550 pounds of explosives — 524 shape charges and 276 pounds of bulk explosives. CST was responsible for preparing the interior beams for the linear copper-clad shape charges. Each charge was composed of 13 pounds of explosives and was wrapped in a reinforced box with layers of reinforcing chain and rubber belting. The reinforcement was necessary to force the energy of the shape charge to cut the steel beams.
The implosion began at the rear of the coliseum. The 524 charges were timed to explode in 52 delays of 500 milliseconds, split into two sequences running concurrently to reduce the concussion from the blast. Overall, the process took about 15 seconds to complete, dropping the roof onto the old floor of the coliseum and toppling some of the walls.
CST has now entered the third phase of the demolition process, which includes demolishing any remaining walls and final clearing of the implosion debris. This will take about four months to complete. Site grading will occur in conjunction with the demolition and will take five months to complete.
More than 90 percent, or 66,000 tons, of material in the structure is being recycled. Approximately 5,000 tons of structural steel is being removed and shipped to a steel plant for recycling. The concrete and other building materials will be ground up and used as fill during the construction of City Park. The asphalt used in the parking lots around the old coliseum will be used for The Loop at City Park, a 3-mile traffic-free walking, jogging and bicycle trail that will link City Park to nearby amenities.
The recycling program is designed to protect the environment and to cost-effectively reuse materials from the coliseum in a beneficial manner. By processing the concrete from the building and asphalt from the parking lots on-site, Pope & Land, the developers, will reduce truck traffic during the site preparation and construction phase of City Park.
Once the demolition debris is completely removed, Skanska USA Building will continue site preparation work along both sides of Tyvola Road, the location of the initial retail and commercial development at City Park. Construction will begin in 2008. When it is finished, City Park, Pope & Land Enterprises' first project in the Charlotte area, will feature 2,500 residential units, 200,000 square feet of retail space, 400,000 square feet of office space, and 350 hotel rooms. The Loop at City Park, mentioned earlier, will link the development to such nearby existing amenities as Renaissance Park, five baseball fields, three soccer fields, an 18-hole golf course, 10 sand volleyball courts, greenspace and 6.5 miles of mountain bike trails, as well as a nearby farmer's market and other commercial property.