Publication Abstract

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

Instrumented Loading Tests to Failure on a Very Long, Steel, Driven, Cast in Situ Multiton Pile
G.F. Rocchi, L.F. Albert & O. Vacca Studio Geotecnico Italiano Srl, Milan, Italy G. Totani Universita dell'Aquila, Italy

The paper discusses the results of two loading tests to failure performed on the same "Multiton" pile (D=18 and 20") at Mortaiolo viaduct, near Livorno; driving depths were of 50 and 57 m, to sandy clayey silt and to sand respectively. Soil profile and geotechnical properties of various layers have been ascertained through in situ and laboratory investigations. Consequences on shear strength and horizontal effective pressures of pile installation have been discussed for two types of clay, one of which is "structured". The pile was heavily instrumented both during installation and load testing; collected experimental data have allowed a complete interpretation with particular focus on the fundamental role of residual stresses. A simplified "t-z" transfer curves model has been adopted, with reconstruction of curves to be used to describe the mobilization of lateral adhesion and base resistance.

 article #485; publication #37 (IC-1991-IT)