A full-scale compressive load test was conducted on a drilled pier in the Pierre Shale Formation near Fort Collins, Colorado, to verify design parameters. The test pier was designed based on presumptive design criteria for both end-bearing and skin friction in the shale. The maximum test load of 6.7 MN (750 tons) resulted in a deflection of approximately 230 mm (9.0 in.). Instrumentation within the pier allowed determination of the actual end-bearing and skin friction values at various applied loads. Based on results of the test, production piers were redesigned for skin friction only and shear rings were added to enhance shaft resistance
