The City of Atlanta is in the midst of a massive expansion at Hartsfield-Jackson Atlanta International Airport, including an Automated People Mover (APM) operating on a 1.5 mile (2.4 kilometer) long overhead guideway and linking the main terminal with an off-site Consolidated Rental Car Facility. The system includes two terminal and one intermediate station and an elevated maintenance and storage facility. The City elected to procure the APM through the design-build-operate-maintain (DBOM) procurement method. The design of the system was constrained by the performance and aesthetic specifications set by the Owner, and clearance requirements for the major facilities crossed. The structural design was developed by Archer Western and Heath & Lineback (H&L) to produce the most efficient solution to the various constraints and to maximize the strengths and expertise of the construction company and led to a unique solution including a variety of structural arrangements. The basic superstructure type is a simple span, single cell precast prestressed concrete box beam. The deck is cast with the box and the deck edges follow the curved alignment of the guideway. The webs and bottom flange of the box are chorded to fit from pier to pier. Several spans had to reach in excess of 120 feet (36.6 meters) and in these locations the box beams were "stretched" increasing the amount of prestressing strands. The lifting and shipping weight had to be limited to 250,000 lbs (1,112 kN) however, so lightweight concrete was prescribed for spans in excess of 120 feet (36.6 meters) to a maximum of 140 feet (42.7 meters). Spans in excess of 140 feet (42.7 meters) up to a maximum of 165 feet (50.3 meters) utilized steel "tub" girders designed to the same shape as the precast beams. Several of the spans were in tight horizontal curvature (radius < 520 feet (158.5 meters)). At these radii it was not feasible to maintain the concept of chording the spans. Two or three span continuous units of cast-in-place post-tensioned box girders were detailed for these locations. The typical substructure element is cast-in-place with a single column pier and hammerhead cap aligning with the box beam soffit.
Guideway Design and Construction
12th International Conference of Automated People Movers ; 2009 ; Atlanta, Georgia, United States
Automated People Movers 2009 ; 428-435
2009-05-28
Conference paper
Electronic Resource
English
Fixed Guideway Construction Improvements
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