Micropiles are a versatile deep foundation type that is typically drilled into the ground and develops load-carrying capacity through the bond between the soil or rock and the cementitious grout that forms the body of the pile. Micropiles are differentiated from similar pile types, like augured piles, drilled shafts and caisson piles by their smaller diameter and reinforcing details. Several variations of the basic micropile concept are available depending on the capacity required and construction methods used, including self-drilling, fully-cased, partially-cased, pressure grouted and post-grouted.

FHWA “Micropile Design and Construction”, Report No. FHWA-NHI-05-039, December 2005.

While micropiles are applicable to a wide range of conditions, they are particularly well suited to retrofit applications in which the site conditions restrict access for equipment. As a drilled pile, micropile installation produces relatively minor vibrations, which reduces the risk of damaging adjacent structures. Micropiles are also well suited to resist foundation loads originating from wind and seismic effects, since they can resist both compression and tension loads. However, due to the cost of micropiles compared to other foundation systems they are not the optimal foundation type for all projects. In addition, they are not usually well suited for high bending loads.

With strong capabilities in foundation engineering and structural engineering, Richard J. Driscoll, Consulting Engineer (RJDCE) is well qualified to assist project designers and contractors select the right foundation system for the structural demands, site conditions and local preferences. RJDCE can evaluate, specify and design a variety of micropile foundation systems, including providing details for reinforcing and pile caps, load tests and other incidental work. In addition, RJDCE can help develop and evaluate the micropile foundation options that best suit the specific application and provide alternatives when micropiles are not the right foundation solution.

See also: Contractor Services, Delegated Design, Foundation / Geostructural Engineering, Underpinning