Scope and field context
Project scope and field context
ATI Companies conducted a geophysical investigation for both URS Corporation and Ardaman and Associates to help determine the cause for the collapse of a supporting foundation pier which occurred during construction of the elevated Leroy Selmon Crosstown Expressway. ATI also conducted an investigation around 45 additional foundation piers where suspected karst-related geological conditions were identified. ATI used multiple geophysical technologies including ground-penetrating radar, high resolution seismic reflection, seismic crosshole shear wave testing, and seismic downhole testing. Results from the investigation indicated the collapsed pier was in the center of a suspected paleo-collapse feature that occurred at a depth range of 80 to over 250 feet below land surface. ATI found an excellent correlation between the weak soils identified in the geotechnical Standard Penetration Test borings conducted and the seismically derived-shear wave velocities.