In 2022, The Federal Aviation Administration nationwide wildlife strike database logged approximately 17,000 wildlife strikes. Standing water near airport runways creates the potential for wildlife strikes, endangering aircraft operations and the flying public. Through funding provided by the Federal Aviation Administration (FAA), the Bismarck Airport has been striving to reduce bird strike hazards by improving stormwater drainage in areas adjacent to aircraft movement areas.
Brierley Associates has been working alongside Bismarck-based KLJ Engineering and the Bismarck airport since 2019, providing trenchless design and construction engineering to install new stormwater collection structures and conveyances beneath existing taxiways, runways and roads without disruption to airport operations. The overall objective of this multi-year program is to promote drainage of water away from aircraft movement areas as quickly and efficiently as possible and convey it to Apple Creek, located on the east side of the airport boundary approximately 1500 feet away from airport operations.
Assessment of stormwater management options by KLJ and Bismarck Airport identified nine separate locations ranging from 75 feet to 750 feet in length and from 8 inches to 42-inches in diameter where new stormwater infrastructure would cross beneath existing aircraft movement areas. Six of the crossings contain two separate parallel pipe installations ranging from 75 feet to 141 feet and from 8 inches to 36 inches in diameter. Given the site constraints and ground conditions consisting of granular and cohesive terrace deposits, Pilot Tube Auger Bore (PTAB) and microtunneling were utilized. Aside from active airport operations, harsh weather and high groundwater, small elevation changes throughout the site challenged the design and construction teams to maintain tight tolerances which forced many trenchless installations to be within 1-inch of design grade. To allow construction flexibility, a mixture of watertight shafts consisting of steel sheeting with wale frames and slide rail shoring with de-watering are being utilized.
Construction of the trenchless installations for Phase 5 and Phase 7 occurred from October 2021 through November 2022. Currently, through Phase 7 of the project, nine of the fifteen trenchless installations have been completed. PTAB pipe diameters range from 8 to 30-inches with reaches varying from 75 to 141 feet. Microtunneling crossings range from 99 to 750 feet in length, utilizing a 60-inch machine to install a steel casing for installation of a 42-inch HDPE carrier pipe.
Brierley trenchless specialists from our Denver, CO, Laramie, WY and Cottage Grove, MN offices provided onsite monitoring, construction engineering assistance and construction management for all PTAB and microtunnel crossings. Our trenchless specialists worked closely with the General contractors (KLJ Construction and Weisz & Sons) and trenchless subcontractors (Iowa Trenchless and Super Excavators) to successfully install the new stormwater assets without disruptions to airport operations.
Management of Brierley’s field team is by Kyle Friedman, PE of our Denver office. Mr. Friedman was honored with a service award that is presented to an outstanding individual of the construction management team for contributing to the successful construction of Phase 5 and Phase 7. “Kyle Friedman continues to be a force multiplier working closely with contractors as both an onsite consultant and first line leader to a young field team… he is a credit to his profession and his employer” said Tony Theurer, KLJ Senior Construction Manager.
Today, work is continuing on the design of the remaining trenchless work to take place in Phase 9 with anticipated construction to take place in 2024. Brierley will be back on-site managing the trenchless installations for the remainder of the project.