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Dartmouth College is expanding its engineering and computer science education and research capabilities with the construction of the MacLean Engineering Sciences Center. The unique geology of the site created challenges for the six story deep foundation. Built on the shore of the Connecticut River, sand composes the majority of the soils. Hitchcock Lake receded 12,000 years ago, leaving the Connecticut River Valley and very deep sand.
Jill Bramblett of Earth Anchoring Suppliers noted, “These conditions were perfect for using CHANCE SS200 and SS225 anchors to tie back the deep retaining wall.” Over 860 square shaft anchors were used to varying depths of 20 to 70 feet.
Bramblett continued, “The engineers choose helical tiebacks over other systems because of the immediate loading and testing capabilities unique to helical anchors… no grout makes installation faster, less labor, more economical, easier to install in winter months.” She added, “If the tie-back doesn’t test out you have the ability to drive it deeper to re-test… you can’t do this with grouted tendons.”
The tiebacks tested to 108 kips and the project took approximately three months to complete. The majority of the six stories below grade will be used as a parking garage for the cutting-edge science facility.
Ancient Glacial Lake Has HB Fleming and Dartmouth College Look to Earth Anchoring Suppliers
By Keith Dolan