<p><p><figure id='attachment_3497' style='max-width:884px' class='caption aligncenter'><img class="wp-image-3497 size-full" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph showing the geofoam placement at the Geofoam Research Center, Syracuse University." width="884" height="540" /><figcaption class='caption-text'> (Photograph courtesy of Geofoam Research Center, Syracuse University; Negussey and Stedlein, 2003)</figcaption></figure></p><p><div><h2>Project Summary:</h2>Interstate I-15 in Salt Lake City, UT was reconstructed to include widening of up to 27 km with six to eight additional lanes, additional high-occupancy vehicle lanes, and reconstruction of 143 bridges and embankments. The upcoming 2002 Winter Olympic games required an accelerated construction schedule. In addition to the calendar time constraints, soft compressible soils and sensitive utilities also drove the design team to consider alternative construction/material methods including geofoam. Over 100,000 m³ of EPS geofoam were used throughout the project.</p><p>Subsurface Conditions at 100 Street South: The upper 7 meters generally consists of alluvial silts and sands followed by 7 to 27 meters of clay with small lenses of sand and silt. Groundwater levels were typically between 2 and 5 meters. N₆₀ values ranged from 4 to 10 and undrained shear strengths varied from 5 to 100 kPa.</p><p>Geofoam was used for 100 Street South embankment to protect a critical utility crossing of a 406-mm diameter high-pressure gas line, a 900-mm diameter storm sewer, and two 1523-mm diameter fiber optic lines. Conventional MSE wall embankments would cause over 1 meter of settlement and were deemed unacceptable. In lieu of soil, a total of 6,000 m³ of geofoam was used. In addition to limiting settlements and accelerating construction, re-routing of these critical utilities was avoided and the amount of right-of-way purchased was limited.</p><p>100 South Street was completed in 10 months (July 2001 to May 2001). Geofoam block was placed in 14 days.<br><h2>Complementary Technologies Used:</h2>MSE Wall</p><p><figure id='attachment_3499' style='max-width:860px' class='caption aligncenter'><img class="wp-image-3499 size-full" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Diagram showing the Section view and instrumentation of the South array from Geofoam Research Center, Syracuse University." width="860" height="335" /><figcaption class='caption-text'> Section view and instrumentation of the South array. (Figure courtesy of Geofoam Research Center, Syracuse University; Negussey and Stedlein, 2003)</figcaption></figure><h2>Performance Monitoring:</h2>Laboratory testing to determine the minimum specified density and compressive strength testing at the desired strain was performed. Settlement monitoring included magnet extensometers, inclinometers, and settlement surveying.</p><p>A total of about 80 mm of foundation settlement was recorded from the start of construction to completion. Post construction settlements were limited to less than 15 mm.<br><h2>Cost Information:</h2>The use of geofoam allowed for completion 6 months ahead of schedule and $32 million under budget.<br><h2>Project Technical Paper:</h2>Negussey, D. and Stedlein, A.W. (2003). “Geofoam fill performance monitoring.” Report No. UT-03-17, Utah Department of Transportation Research Division, 45p.<br><h2>Date Case History Prepared:</h2>November 2012</p><p></div></p></p>