Micropiles are used extensively for underpinning or retrofit of existing foundations. In
some cases, micropiles must be preloaded to reduce excessive settlements and to
prevent overloading of the existing foundations when the new or additional load is
applied. In this aspect, the preload must be properly and permanently locked in the
head of micropiles. This paper describes a newly developed preloading and head
connection method for micropile, provides a means of more efficiently enhancing the
micropile-to-footing connection capacity and increasing the load carried by micropiles.
An experimental study was conducted to investigate the total capacity of the micropileto-
footing connection. The results of tests showed that the developed micropile
preloading systems (i.e., steel cone and split-threaded wedges) could provide costeffective
engineering solution for strengthening existing foundations and increase the
structural capacity of the micropile-to-footing connection.
Subjects: preloading and head connection, micropiles
Author: Je-Yong Park, Changho Choi, Hyun-Sik Yu, Hee-Jeong Yang, Ki-Hwan Lee
Publisher: ISM, DFI, ADSC