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Hartsfield-Jackson International Airport 5th Runway Project
As one of the “world’s busiest passenger airports,”
Hartsfield-Jackson International Airport is embarking on a
ten year development plan to modernize and expand the
current facilities to meet future demand. United Consulting
is proud to be part of the expansion plan as a member of the
design/build team for the 5th Runway Bridge Taxiway.
The bridge is 735’ wide and 910’ long and spans the
east-bound and west-bound lanes of I-285. The immense
structure must support the extremely high loads of aircraft
landing on the runway as well as the dead-weight of the
concrete structure itself. We engineered the solution,
recommending and monitoring the installation of a
combination of 280-ton steel piles and shallow foundations.
Controlling settlement at the transitions from the bridge to
the soil-supported runway is critical. Soil depths at each
end of the bridge range from 40 to 125 feet. Some of the
soil is very soft, while some of the upper layers include
engineered fill. Without a solution, settlement in the areas
of maximum fill was calculated to be in the range of 16 to
24 inches over a two-year period. Not good enough. In order
to provide safe landings and take-offs, settlement must be
limited to ½ inch over 20 years on the 5th runway.
Engineers and scientists at United Consulting researched
many possible solutions and ultimately decided on a
combination of techniques. Below the water table, wick
drains were installed to provide a path for the water to be
squeezed out of the soft soils. For material above the water
table, a deep dynamic compaction technique was used to
densify the near-surface soils. Drainage blankets were
installed in the fill material above original grade to
accelerate settlement.
The entire team is confident that, when completed, the 5th
Runway Bridge will perform well, providing safe and takeoffs
landings for Hartsfield-Jackson passengers for years to
come.
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