Summit Geoengineering Services provided geotechnical consulting for the Northern New England Passenger Rail Authority (NNEPRA) layover facility in Brunswick, Maine.
The layover facility is described as a building structure that has a 46,000 square foot footprint with a height of 37 feet to accommodate up to three locomotive train sets. Cooper E80 train loadings were used for soils engineering. Geotechnical challenges included a deep sand marine regressive delta with shallow groundwater within a sand and gravel aquifer. A combination of test borings with SPT sampling, groundwater observation wells, and seismic cone penetration tests (SCPTu) were performed by SGS using an AMS PowerProbe 9500 VTR to investigate the subsurface conditions. The use of SCPTu provided site specific shear wave velocity testing for improved earthquake seismic design, liquefaction analysis, and soil response from dynamic train loads.