Photo courtesy of USACE
The building’s massive size required 12,000 trips from concrete trucks to unload 9,600 cu. yds. of concrete.
Large construction projects rely on teamwork for success. One such successful undertaking is bringing new life to a large intelligence agency located in St. Louis. The National Geospatial-Intelligence Agency (NGA) is spread out in several locations around the city, some of them more than 100 years old. One of the structures was located on an old Civil War arsenal.
The Department of Defense (DOD) recognized the need for a complete overhaul and called on the US Army Corps of Engineers (USACE) to build a new secure campus. The first two team members were in place, but they had to decide where to build the facility.
Several communities bid for the project, but St. Louis won by securing and remediating a 97-acre plot in north St. Louis. The area was economically depressed. The NGA project promises to bring some 3,100 full-time workers to the facility.
Photo courtesy of USACE
Once the location was selected, McCarthy HITT, a St. Louis-based joint venture, was selected as the design-build firm. More subcontractors were selected, about 100 in all, and the work began under the watchful eye of NGA. The agency kept a close look at materials, personnel and design for the facility to ensure security.
The project began in 2019 and has utilized a workforce that is just under 15 percent minority-owned contractors and nearly 7 percent women-owned companies.
Former Congressman William Lacy Clay calls the new NGA site "an oasis growing out of the desert. Hopefully, this sets an example to invest in an area that had previously never been invested in my lifetime."
The DOD is spending $1.7 billion to make this oasis a reality. The USACE is developing a project that carries some unusual requirements. The three-story structure must meet military standards for blast resistance and uninterruptible power. Much of the building needed to be built to sensitive compartmented information facility (SCIF) standards. The 16-in.-thick concrete walls were made in a secure facility by Enterprise Precast in Omaha, Neb.
Gene Morisani of the USACE is the program manager for the massive project. The construction team will be delivering a 700,000- sq.-ft. main office, complemented by two 467,000-sq.-ft. parking garages. The team also will be building a visitor's center and supervising construction of roads and walkways for the campus. In addition, workers installed all utilities, water lines, fire facilities and power including a substation connected with the local utility. The new NGA also will house secure areas for the agency's geographic information systems (GIS) and other data.
Similar to Military Base
"We are building what is essentially a small military base," said Morisani. "In the beginning stages, we drilled piles for the foundation of the buildings. Our team drilled some piles 30 feet deep to reach solid rock while others only need to go down 10 feet."
The team drilled more than 300 piers for the structures, according to Morisani.
The building's massive size required 12,000 trips from concrete trucks to unload 9,600 cu. yds. of concrete. The building has used some 6,000 tons of structural steel.
"Our builder had the basement and foundation walls up by April 2021," said Morisani. "We put the structure up and closed it in by November 2022. Steel erection took one year. We are expecting the building to be occupied by 2026. NGA personnel will carefully screen everything before the move-in date."
Photo courtesy of USACE
With its precast concrete skin, the building looks like a large ordinary office building. However, the security and insulation that is part of the construction resists sound and radio transmission, helping to keep future communications secure.
Morisani and his team opted not to use a tower crane for the construction, instead employing multiple crawler cranes.
"Our team used the smaller cranes to move around the building more easily and access tighter spaces. We also used mobile belt conveyors to transport rock where we needed it. We also used rough-terrain cranes from outside the building footprint to hoist punch windows into place. The windows were quite heavy and needed this equipment for lifting the windows three to four stories high."
Castle Contracting, McCarthy's civil contracting sister company, managed mass excavation and site utility work under a separate contract. Castle's scope included more than 615,000 cu. yds. of mass grading as well as structural excavation, soil stabilization and a stormwater pollution prevention plan. To support stormwater management, Castle installed six runoff holding areas for groundwater, including detention ponds, detention structure and cooling water/irrigation pond. Stormwater runoff will be used for mechanical cooling and irrigation.
Unique Elements
- The underground detention basin was the largest in North America (based on ADS's designers) and required a lot of rock excavation.
- Special equipment included a long-reach excavator to dig a detention basin along with a fleet of scrapers.
- For the water line, Castle assisted with cathodic protection.
At peak, Castle used five haul trucks, six scrapers, four track hoes, three bulldozers and compactors. A long-reach excavator was used for remediation and automated GPS equipment was used on excavators and dozers to expedite construction.
Photo courtesy of USACE
Safety has been a high priority for the Corps and for McCarthy HITT. The construction team recently reached an important milestone.
"We recently hit the 3 million man-hours mark on the project without a major incident," said Morisani. "That's quite an accomplishment with hundreds of workers on site every day. We are big on personal protective equipment and hazard analysis."
One way the construction team has been able to reach that mark is by avoiding the use of common ladders. The team has encouraged workers to use a lift whenever possible. The workers also use many platform-style ladders, which are safer than normal ladders.
Josh Gaghen, vice president and project executive of McCarthy Building Companies, commented on the significance of the project.
"The greatest challenge involved managing the security and specialized requirements on a purpose-built, one-of-a-kind facility," he said. "It has been truly incredible to be part of a best-in-class facility that supports national defense and will serve as an outstanding workplace and asset in the city of St. Louis." CEG
Chuck MacDonald
Chuck MacDonald is an editor, blogger and freelance feature writer whose writing adventures have taken him to 48 states and 10 countries. He has been the editor for magazines on pavement construction, chemicals, insurance and missions. Chuck enjoys bicycling, kayaking and reading. He graduated from the University of Missouri with a degree in journalism. Chuck lives in Annapolis, Md. with his wife Kristen. They have seven grandchildren.
Read more from Chuck MacDonald here.
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