We provided geotechnical engineering services for the approximately 1,100-foot extension of Runway 14-32 at the SAB Municipal Airfield. Project highlights included the design and construction of 1.5H:1V embankments, one of which was 75 feet tall, to support the runway extensions while limiting encroachment on adjacent wetlands and properties. Additionally, the borrow source for the 440,000 cubic yards of material needed to construct the embankments was mined from an immediately adjacent town-owned property, limiting the need to truck fill material to the site.
The Solutions Unearthed
- We performed subsurface explorations and laboratory testing to evaluate the suitability of town-owned property as a source of fill material and to determine the suitability of existing runway material for reuse and reclamation.
- Original plans considered a Reinforced Soil Slope. Upon completing our evaluation of the adjacent town-owned borrow source, we recommended switching the design to a more cost-effective embankment design with a common fill core and an outer shell of rockfill. This eliminated the need for geosynthetics and imported select material at the embankment face.
- Design of two embankments to support the runway extensions included a 75-foot high, 1.5H:1V slope embankment at the Runway 14 end to limit encroachment upon surrounding wetlands. At the Runway 32 end, a similarly steep slope was utilized for the 40-foot high embankment to limit encroachment upon private property while allowing room for the relocation of a town road around the end of the embankment.
- We provided construction engineering and inspection services during construction of the embankments.
Client: DuBois & King, Inc.