Publication Abstract

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

The use of 'Bounded Fluid' Preloading Cells for the Foundation Piles of a Viaduct on the High-speed Freeway in Naples
A. Bellini, R. De Domenico, L. Gagliardi & P. Polenghi

This paper describes the use of preloading cells, which have been conceived and designed as "bounded fluid cells" by Dr. P. Sembenelli, Eng. These cells have been installed and pressurized at the base of foundation piles with a diameter of 1200 mm, at a depth of 30 m. The piles in question represent the foundations of the piers of a viaduct on the new high-speed freeway being built in Naples in the area around Corso Malta. The preloading cells were designed to reduce the settlements that may otherwise have resulted from the statically indeterminable structure of the viaduct and the nature of the ground, which consists chiefly of the pozzolana typical of the Naples area. Their design took account of the need for ease of installation and working and they took the form of a membrane that could be expanded by means of the injection of cement mixtures after the concreting of the piles. Special materials were used in order to achieve optimum performance during the graduated injection operations for preloading the bearing surface of the piles, the base of which had to support most of the load. The paper also describes a series of load tests carried out on piles with preloading cells and gives an interpretation of the results obtained.

 article #508; publication #37 (IC-1991-IT)