Dulles Pedestrian Walkback Tunnel

The Dulles Pedestrian Walkback Tunnel is part of a $3.4 billion capital construction program at Dulles International Airport. As one of the fastest growing airports in the world, Dulles Airports Authority was faced with the challenge of moving passengers more efficiently. The previous method of transporting passengers from the Main Terminal to the outer gates involved an obsolete method of boarding a mobile docking lounge for a two- to five-minute ride. Kiewit was awarded a contract in December 1999 to alleviate the problem by constructing a passenger tunnel from the Main Terminal to Terminal B. The Dulles Walkback Tunnel was the first phase in providing improved access to the outer terminals.

Crews constructed a 185-foot, open-cut ramp in the infield between the Main Terminal and Terminal B. The open cut was supported with soil anchors and shotcrete. From the cut, a 760-foot tunnel measuring 40 feet wide and 27 feet high was excavated under a live taxiway using New Austrian Tunneling Method techniques. The initial tunnel lining included lattice girders and fiber reinforced shotcrete. The final tunnel lining consisted of PVC waterproofing and reinforced cast-in-place concrete.

The project also included selective demolition and reconstruction work at the Main Terminal, a 110-foot pedestrian bridge to the Main Terminal, support and construction of two buildings, and conversion of 5,300 square feet of office space into public restrooms. In addition, the tunnel was equipped with escalators and moving walkways.