Buckling of Micropiles

Building codes and common design practices generally assume that the lateral support provided by the soil is sufficient to prevent buckling of fully embedded piles. As small diameter grouted piles (micropiles) have evolved from relatively low capacity friction piles to current applications that include high capacity elements, there is a need to revisit the issue of potential buckling of these very slender piles when embedded in soft soils. Pile buckling loads obtained from a semiempirical relationship are compared to the allowable loads permitted by current and proposed codes and design guidelines. It is concluded that buckling is generally not a concern for the most common types of micropile design, but there are some designs permitted under the codes and design guidelines for which buckling may be a controlling design factor.