EG Solutions was the Engineer of Record for the project in response to a part 139 inspection that found deficiencies in the Runway Safety Area (RSA) caused by drainage swales and structures. Also, the Wildlife Hazard Management Plan (WHMP) for the airport recommended removal of areas of vegetated and standing surface water to the extent practicable on the airport.
The project consisted of changing the conveyance system for Runway 14-32 and the parallel taxiways from open swales to enclosed culverts. It also required upsizing of existing culverts with insufficient capacity acting as chokepoints to water flow. This included replacing a double 30-inch pipe beneath Runway 14 with a double 29 x 45-inch horizontal elliptical pipe. The horizontal elliptical pipe was a valued engineered option to the originally designed double 2 x 4 foot box culvert, providing roughly equivalent conveyance in improvement above that available from the swales.
Helping minimize the disruptions to the Runway 14-32 rehabilitation project, the pipe replacement beneath the runway was done as the first element of the work. It involved excavations of soil and rock followed by pipe setting and backfill with flowable fill/Controlled Low Strength Material (CLSM). The pipe replacement achieved the accelerated schedule associated with runway and taxiway pavement crossings using this approach. Outside of pavement crossings, the pipe was backfilled with granular material consisting of pea gravel to the spring line covered by sand with gradation consistent with raveling prevention. Pipe joints were also wrapped to help prevent raveling.