A Bi-modulus column combines a ballasted material head (Vibro-Replacement) with a controlled modulus column (CMC).

Controlled modulus columns are produced in the first phase, with concrete stopping at least 1 m above the Bi-modulus column interface level to ensure continuity. After an initial curing period, there is a window of a few hours to produce the column head systematically made of a covering over the head of the CMC.

Bi-modulus columns perform especially well in truncated soil. They also reduce the depth of the distribution bed or can be used in seismic zones.