Electric Boat announced Friday that it signed a $544 million contract with Los Angeles-based AECOM to construct a 200,000-square-foot building, where 1,400 shipbuilders will assemble a new fleet of ballistic-missile submarines.

The new building is the centerpiece of an $850 million expansion project in Groton. Overall, the company is investing $1.7 billion to modernize and upgrade its facilities in Connecticut and Rhode Island.

EB is the prime contractor for the 12-ship Columbia-class program, which will replace the aging fleet of Ohio-class ballistic-missile submarines built in the 1980s and '90s.

Early construction began in 2017 at the company's facility in Quonset Point, R.I. Final assembly and testing will take place starting in 2024 in Groton.

"General Dynamics Electric Boat continues to make investments — in facilities, in our supply chain and in the next generation of shipbuilders — to support the Columbia class, the Navy’s top strategic priority," company President Kevin Graney said in a statement.