Long-Term Instrumentation Program to Monitor Various Geotechnologies Used on I-15 Reconstruction Project, Salt Lake City, Utah (05-1480)
Clifton B. Farnsworth, Brigham Young University
Steven F. Bartlett, University of Utah

The Utah Department of Transportation (UDOT), in conjunction with Wasatch Constructors, recently reconstructed a 27 km (16.8 mile) portion of Interstate I-15 in Salt Lake City, Utah. As part of this $1.5 billion design-build project, several types of innovative foundation and embankment treatments were used in order to expedite construction on soft, clayey foundation soils. Currently, the UDOT Research Division is monitoring and evaluating the construction and long-term performance of four different geo-technologies utilized during the reconstruction project: lime cement columns, two-stage MSE walls on soft soil sites, geofoam, and large earth embankments on soft soil sites. This is known as the I-15 Foundation and Embankment Performance project. A total of twelve arrays have been installed along the I-15 corridor to gather performance information. The instrumentation for each array was installed to meet specific objectives relating to each geo-technology type. The information learned from this project is being used to validate the geotechnical design used for the I-15 reconstruction project and to improve the state-of-practice in designing earthen structures and other geo-technologies associated with construction on soft, clay foundations. This study was initiated in the summer of 1998 and is expected to continue for a 10-year post-construction period. The funding for the instrument installation and monitoring was obtained in conjunction with the I-15 National Test Bed Program. This paper provides a valuable case history of the implementation of a long-term instrumentation-monitoring program.