Lunar geotechnical engineering, popular GeoPrac content for June, Dead Sea sinkholes and a toppled building in Shanghai are all featured in the 5th issue of the GeoPrac.net monthly newsletter for July of 2009. You can read it in the newsletter archives, and be sure to subscribe to future issues.
Univ. of Missouri’s Historic Memorial Union, Built to Honor WWI Dead, Gets New Life with TerraThane Geotechnical Foam
MOUNT AIRY, NC—The Univ. of Missouri’s iconic Memorial Union, with its Gothic architecture and central bell tower, was built to commemorate the 117 Mizzou alumni who lost their lives in WWI, and has been under silent attack. Like all buildings built atop the ancient dry riverbeds of the tributary valleys of the Missouri River, the soil beneath is a mixture of sand, clay, and fine rock particles and highly susceptible to erosion from water. So, while hundreds of thousands of students walked the hallways of the building, water escaping steam pipes far beneath caused severe drying of the soil and destabilized it enough so that erosion created voids, or cavities in the soil, some as large as four feet. In turn, this caused the concrete slab floors atop the voids to become uneven, and the eventual danger of even greater problems loomed large.
A team of engineers went after the problem, including MU alums, Matt VanderTuig, P.E., of Bartlett & West, Jefferson City, MO, and Mark Whitehead, P.E. with extensive structural design and environmental engineering management experience. They suggested to Chris Hentges, president of SIRCAL Contracting, Jefferson City, the general contractor in charge of the job, that instead of using the older method of mudjacking, a highly involved and intrusive process of drilling large holes in the slabs—sometimes removing the slabs entirely—and pumping “mud”, ultra-heavy Portland cement-based grout, into the void, then leveling the slabs, that the university might better be served by using the newer polyurethane foam system method called “foamjacking” or “polyjacking.”
[Editor] Be sure to click through for the rest of the interesting project from GeoPrac sponsor NCFI Polyurethanes and TerraThane! [/Editor]