Although work has been underway for months on the site of the new Atlanta Braves stadium in Cobb County, the team plans to hold a formal groundbreaking ceremony Sept. 16.

The Braves said Tuesday that the ceremony will mark the start of the construction phase of the project, “putting it on schedule to host fans for opening day 2017.”

To this point, much of the work on the site has been related to the relocation of two gas pipelines from the heart of the property to the periphery. The previously forested site has been largely cleared.

The Braves have released only preliminary conceptual renderings of the $622 million ballpark, but Derek Schiller, the team’s executive vice president of sales and marketing, told The Atlanta Journal-Constitution last week that more detailed plans will be unveiled “before the end of the season.”

“We have had some really good breakthrough architectural-design meetings here,” Schiller said.

In a news release announcing the groundbreaking ceremony, the Braves said the stadium will combine “a classic ballpark feel” with modern amenities.

The stadium will seat 41,500, with the upper and middle of three decks cantilevered over each lower deck to push seats closer to the field, Braves officials have said.

Preliminary drawings show a large canopy — about three times the size of the Turner Field overhang — horseshoeing around the stadium’s top to provide some protection from sun and rain. Typical of recently built stadiums, the Braves plan more indoor spaces and club areas than at Turner Field. Concourses will be wider, most with direct views to the field, the team has said.

The Braves said in Tuesday’s release that the home-plate side of the ballpark will “nestle into the hillside” on the gently sloping site.

The Sept. 16 ceremony is scheduled for 11 a.m. at the site near the northwest intersection of Interstates 75 and 285. The ceremony won’t be open to the public.

The Braves said construction will begin later on an adjacent mixed-use complex that they plan to open simultaneously with the ballpark in 2017.