Publication Abstract

Proceedings - Fourth International Conference - Piling and Deep Foundations, 1991, Stresa, Italy, (DFI)

Steel Bottom/Driven Piles in Coral Formations Problems: Skin Friction Improvements Method
F. Danese; Cogefarimpresit SpA, Italy G. Botto: Italsonda SpA, Italy

A new grouting system is described, carried out externally to the terminal part (4 mts.) of the shafts of bottom driven steel piles into a coralline (micrite) formation as foundation for a new wharf at the Port of Zanzibar (Tanzania). It is well-known that driving piles into this kind of fragile and spongy rock comminutes it, and that the resulting detritus remains as an inclusion between the shaft of the piles and the surrounding unbroken rock. The load-bearing capacity from skin friction is considerably reduced in consequence. The cement consolidation operation carried out at Zanzibar and described here restored the adhesion between the shafts of the piles and the rock, so that they could support the designed loads. Altogether 437 piles were driven, with diameters from 600 to 700 mm and a total length of 12,000 meters, achieving excellent results. It is believed that this low-cast method, which saves a great deal of execution time, will be found to be interesting in similar cases.

 article #471; publication #37 (IC-1991-IT)