Barrettes are load-bearing elements that are excavated rectangular piles used as foundations to resist
large vertical and significant horizontal loads that can accompany the construction of diaphragm walls.
how they work:
The same techniques utilized in diaphragm wall construction can be used to form individual barrettes of various shapes including I, T, X or L to accommodate top-down construction.
why you need them:
Barrettes provide resistance to horizontal stress and to bending moments better than circular piles of the same section, so that one single pile is sufficient under each column or bearing element.