Image Source: Clarke Construction

Shotcrete Ground Support for the Atlanta Plane Train Tunnel

Client: City of Atlanta
Contractor (PDB JV): Clark Construction / Guy F. Atkinson Construction / Technique Concrete Construction
Design: Delve Underground (lead designer); STV (designer/architect); McMillen Jacobs Associates (lead tunnel designer)

Opened in early 2025, the Atlanta Plane Train Tunnel West Extension at Hartsfield-Jackson Atlanta International Airport extends the automated people mover system by approximately 700 feet (213 m) to improve train turnback operations and increase capacity. Constructed using the Sequential Excavation Method (SEM), the works included twin tunnel sections transitioning through a large bifurcation chamber into a single running tunnel.
Excavated approximately 60 feet (18 m) below ground, the typical running tunnel sections are about 24 feet (7.3 m) in diameter, with enlarged sections at the bifurcation. Primary support comprised fibre reinforced shotcrete and lattice girders, followed by waterproofing and a cast-in-place concrete final lining.

The project has been recognised with multiple regional and industry awards, including ENR Southeast Best Projects and design-build awards acknowledging construction quality, safety performance and innovative engineering

The excavation ground support comprised lattice girders, dowels and fibre reinforced shotcrete forming the initial lining. BarChip macro synthetic fibres were specified within the shotcrete mix to provide dependable residual capacity, durability and crack control in demanding conditions. The fibre reinforced mix was subject to detailed preconstruction trials and ongoing quality verification to confirm strength development and in-situ performance. The result was a robust primary support system enabling safe and efficient tunnelling beneath one of the world’s busiest airports.