DFI Traveling Lecture at ASCE Geo-Institute Graduate Student Chapter at University of Texas

February 2019
University of Texas
Austin, TX
The 2018-2019 DFI Traveling Lecturer John R. Wolosick, P.E., D.GE, F.ASCE will be delivering his presentation on
Micropile Foundations for Spallation Neutron Source (SNS), Oak Ridge National Laboratory, Oak Ridge, Tennessee. The U.S. Department of Energy (DOE) has built the world’s newest accelerator-based, pulsed-neutron system, called Spallation Neutron Source (SNS). The facility, located in Oak Ridge, Tennessee, is a partnership of six DOE national laboratories — Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos and Oak Ridge. SNS provides opportunities for up to 2,000 researchers each year from universities, national laboratories and industry from around the world for basic and applied research and technology.

This state-of-the-art research facility provides neutron beams that are 12 times more intense than any other such source in the world. Micropile design load capacity is 400 kips axial compression and 20 kips lateral. The axial load is transferred to sound rock through a 10-foot rock socket using side friction. The typical micropile consists of an inner casing (9-5/8 inch O.D. x 0.545 inch wall) and an outer casing (11-3/4 inch O.D. x 0.545 inch wall). The inner casing extends full length from the bottom of the mat into the sound rock and the outer casing extends 20 feet from the bottom of the mat. The pile is installed in a 14-inch diameter drilled hole, extending 10 feet into sound rock. The interior of the casing and exterior space around the casing is filled with 5,000 psi cement grout. The outer casing in the upper 20 feet provides additional resistance to bending from lateral loads.