WASHINGTON, DC-Capitol Crossing, a unique mixed-use development planned for the three blocks of the recessed portion of I-395 in Downtown Washington, has taken a major step forward. Property Group Partners has acquired the fee interest in three blocks of the project and plans to begin development in 2013.

The project is among the most ambitious–to say nothing of innovative–proposed for the District. The project will be built, in part, on a platform that will be constructed over the Interstate connecting Capitol Hill to the East End.  Designed for LEED Platinum certification, the project will span Massachusetts Avenue on the north to E Street on the south and cover the expressway between 2nd and 3rd Streets NW. Ultimately it will create seven acres of property when completed. The specific financial terms have not been disclosed.

Capitol Crossing is by far the most creative project that we have ever tackled, says Jeffrey Sussman, president of PGP, in a prepared statement. “Thanks to our partners and scores of District and Federal officials who helped us reach this point, we can move forward to make this long-awaited dream a reality.”

Plans call for five buildings to be built on the site, one 150-unit residential building and four office buildings of between 300,000 square feet and 685,000 square feet. All of these buildings will be built to 130 feet. The 180,000-square foot residential building will be at 600 2nd St., while the four office buildings will bear the addresses of 200 Massachusetts Ave., 250 Massachusetts Ave., 200 F St. and 201 F St. These buildings will be 407,000, 546,000, 685,000 and 297,000 square feet, respectively.

Skidmore, Owings & Merrill designed the master plan for the project, and Kevin Roche John Dinkeloo and Associates and Kohn Pedersen Fox Associates are design architects for the north and south block office buildings, respectively. NAI KLNB served as originating broker, and a team of leasing brokers from Cassidy Turley represents PGP as the designated leasing agent for the project.

This project has been decades in the making, propelled forward by Property Group Partners—then called Louis Dreyfus Group. The centerpiece of the project will be the unique platform that will not only unify the project, but also allow the buildings to plug into a novel ecosystem.

“Buildings will have access to sustainable components that other buildings on terra firma wouldn’t have,” Sean Cahill, vice president of development at PGP, told GlobeSt.com in an earlier interview. “There will be water storage in enormous quantities, rainwater and underground water, that we will capture and treat and put back in the buildings.”