New Deep Foundations Cut Costs

Davidson, Richard R.; ,

New Deep Foundations Cut Costs

by Richard R. Davidson, Sr. Proj. Engr.; Woodward-Clyde Consultants, Denver, CO,

Serial Information: Civil Engineering—ASCE, 1987, Vol. 57, Issue 12, Pg. 54-56

Document Type: Feature article

Abstract:

Two European innovations in deep foundations are highly competitive in cost, time and material. They are the barrette (slurry wall segment) and the bored pile/caisson which is then grouted around its sides and underneath. Their first use on projects with U.S. involvement were two constructed in 1983-84�the Lucky-Goldstar Corp. headquarters in Seoul, Korea, using barrettes, and the U.S. Embassy in Cairo, Egypt, using the grouted bored pile. In Cairo, there would have been a 6-month delay in delivery of the planned step-taper piles, instead grouted bored piles were constructed immediately saving $1 million, because their capacity was so great (up to 450 tons) that fewer could be used. In Seoul, barrettes saved money because slurry-trench construction equipment was already on site to build the underground wall around the basement. Originally, large diameter caissons founded in rock were planned. However, there were no large caisson-drilling rigs in South Korea, and only after great expense and delay could they be brought in. As for U.S. application, the grouted bored pile, pioneered by the German firm Bauer, may save money where very high column loads are planned for buildings over sand. Barrettes may be most attractive where a slurry wall is to be built around the basement perimeter. Another advantage is depth�caissons' depth is limited by the length of Kelly bar, while barrettes could be built 400 ft deep and more, using cable clamshell and chisel equipment.

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