The Tower at First National Center?- Omaha, Neb.
Completed on time and under budget the 46-story, granite and glass Tower at First National Center forever changed Omaha's skyline. The project's scope of work included a 633-foot-tall office building; a 300-stall, seven-level attached parking structure; two underground tunnels; and a 10,000-square-foot winter garden.
Preparation for construction began with foundation work for the giant pile cap. The Tower's elevator shaft is supported on 28 90-inch-diameter drilled shafts, which are socketed into bedrock. Each shaft is approximately 63 feet deep and contains 100 cubic yards of concrete.
Once excavation was complete, crews poured the 120 feet by 76 feet by 12.5 feet deep pile cap. This was Nebraska's largest continuous concrete pour ever, taking 11 hours to complete. Kiewit provided quality control services and construction design to ensure that 1.9 million pounds of reinforcing steel would be held firmly in place throughout the pour. After the pile cap was poured, wall pours on the central core commenced. Nearly 330 cubic yards of concrete were placed into wall forms to an average height of 13 feet 6 inches. With the concrete core topped out, crews installed the last of the structural steel and the building's exterior skin, which comprised hundreds of unitized aluminum, glass and Italian granite panels.
For its exemplary safety record and participation in the Occupational Safety and Health Administration's Voluntary Protection Program, the Tower project received the highest level of achievement – Star status.