<p><p><figure id='attachment_3368' style='max-width:952px' class='caption alignnone'><img class="wp-image-3368 size-full" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Diagram of pile supported load transfer platform for widening of Minnesota Trunk Highway 241." width="952" height="525" /><figcaption class='caption-text'> Schematic of the foundation system showing the pile-supported embankment. (Wachman et al. 2010; With permission from ASCE)</figcaption></figure></p><p><div><h2>Project Summary/Scope:</h2>A pile supported embankment was constructed on Trunk Highway (TH) 241 near St. Michael, MN, about 2,000 feet southwest of the I-94/TH 241 interchange. This project involved the widening of a highway from two to four lanes. The new embankment was a widening of an existing embankment. Differential settlement between the new embankment section and the old section was a concern.</p><p>Subsurface Conditions: 30 feet of highly organic silt loams and peats underlain by 20 feet of silty organic soils. Below that is 12 feet of loamy sand underlain by 35 feet of gravelly sand. A well-cemented sandstone lay 100 feet below the ground surface. The section of highway is bordered on the northwest by a small pond and on the southeast by marshy terrain</p><p>Pile spacing was 7 feet on-center and the diameter of pile caps was 2 feet. The Load Transfer Platform (LTP) embankment was designed using the beam design method. Piles consisted of steel pipes filled with concrete. Four layers of geosynthetic reinforcement were used with granular fill. The total thickness of the LTP was 3 feet (~ 1 meter). Backfilling of the embankment was completed on October 10, 2006. Instrumentation data is presented through June 4, 2007.<br><h2>Complementary Technologies Used:</h2>Geofoam lightweight fill, reinforced soil slope, and geosynthetic construction platform stabilization technologies were also used for this embankment widening.<br><h2>Performance Monitoring:</h2>The embankment was instrumented with 48 sensors including strain gages, earth pressure cells, and settlement systems. Settlements, geosynthetic strains, and pile strains/loads are presented in the technical paper for an approximately 18‑month period following construction. A finite element analysis was performed using STRAND7. Instrumentation results are compared with the finite element analysis.<br><h2>Case History Author/Submitter:</h2>Rich Lamb, P.E.<br><a href="http://mrd.mail.yahoo.com/compose?To=Rich.Lamb%40dot.state.mn.us">Rich…;(651) 366 - 5595<br>Foundations Engineer<br>Mn/DOT Office of Materials, Mailstop 645<br>1400 Gervais Avenue<br>Maplewood, MN 55109<br><h2>Project Technical Paper:</h2>Wachman, G.S., Biolzi, L. and Labuz, J.F. (2010). “Structural behavior of a pile-supported embankment,” <em>Journal of Geotechnical and Geoenvironmental Engineering</em>, Vol. 136, No. 1, pp 26-34.</p><p><a href="http://ascelibrary.org/action/showAbstract?page=26&amp;volume=136&amp;i… Case History Prepared:</h2>November 2012</p><p></div></p></p>