In response to increased demand, Dulles International Airport's ambitious D2 program included a network of tunnels for new systems:
- Automated People Mover (APM) system
- Pedestrian tunnel
- Underground baggage conveyors
- Underground roads for the airport tugs
- Utility tunnels
The APM System would replace most of the Mobile Lounges that transport passengers between the terminal and concourses. The lounges would continue to be used to serve aircraft that do not have access to gates and for unscheduled or emergency situations.
Phase 1: Detail Design and Design Management for the APM, baggage, and tug tunnels.
Mott MacDonald's scope included tunnel structures, mechanical/electrical systems, ventilation systems and fire/life safety design for all tunnels and the Vehicle Maintenance Facility. All design elements were progressed through feasibility studies and analysis of alternatives to 60% completion.
In addition, we performed management and design coordination of security and communication systems for both the tunnels and vehicle maintenance facility.
However, following the events of September 11, the Authority, like all airports nationwide, was required to reevaluate its construction plans. Decreased passenger figures and new security requirements caused some adjustments to prioritizing projects and schedule. The first segment of the APM connecting the Main Terminal and Concourses A, B, and C, was opened in January 2010.
Phase 2: Pedestrian Tunnel Extension
Following a reassessment and updating of the deferred Phase 1 work to suit current airport requirements, Mott MacDonald led a team of 10 subconsultants to complete the design of the Pedestrian Tunnel Extension, twin 35-foot-diameter TBM tunnels 35 feet (11 meters) in diameter and 2,800 feet (853 meters) long that link to a cut and cover tunnel for a baggage conveyor system, and an extension of the West APM Twin NATM Tunnels.
The D2 project increases capacity and efficiency at one of the main airports serving the US capital.