Publication Abstract

Proceedings of the 30th Annual Conference on Deep Foundations, 2005, Chicago, Illinois, USA, (DFI)

Vertical Bearing Capacity of Pile Installed by “EX MEGATOP” Method – Base Enlarged Pre-boring and Grouting Method for Pre-cast Pile
Sadao Yabuuchi Dr. Eng., Hitoshi Ogura Dr.Eng., Koichi Kobayashi Dr.Eng.

In Japan, most pile foundations using pre-cast concrete piles are installed by the bored pre-cast piling method, wherein pre-cast piles are installed in holes that have been excavated beforehand and filled with cement milk (term used for cement water slurry in Japan). The bored pre-cast piling method with enlarged base, in which the portion near the toe is enlarged during boring operation, is widely used because of the cost benefits and the increased vertical bearing capacity that this method offers. The EX MEGATOP method, further developed as an improved bored pre-cast piling method with enlarged base, is reported here. The features of this method are: (1) High vertical bearing capacity; (2) High degree of freedom in design; (3) Excellent workability; and (4) Friendly to the environment. In particular, high vertical bearing capacity can be obtained using modular piles and by enlarging the area at the pile toe and shaft. This method can give a vertical bearing capacity coefficient at the toe of ?=430, more than twice the corresponding value of ?=200 of a conventional bored pre-cast pile. Moreover, the shaft resistance can be several times larger than that of a conventional bored pre-cast pile. This report gives an overview of the EX MEGATOP method, evaluation of vertical bearing capacity, and examples of application of the method.

 article #1304; publication #72 (AM-2005)