Applications and Techniques

Bi-modulus column techniques were developed in the early years of the 21st century in answer to the continuously growing demand for more buildable land. Bi-Modulus Columns combine a concrete column for the lower part topped by gravel material and are designed to reduce soil settlement and increase the load bearing of sub standard soils. Bi-modulus columns have been found to be particularly effective in cases of deep cut-off, to avoid unwanted movements in slabs on backfill or in seismic zones.

IMPLEMENTATION

A concrete column – such as Controlled Modulus Columns/Rigid Inclusion columns - is installed first using a displacement tool or vibrating tube to achieve the required depth. Ensuring an adequate interface level to guarantee continuity a granular top is placed on top of the concrete column. The size of the column head, just as that of the concrete column below it, will be individually defined to satisfy the project demands and characteristics but is usually between 1.0 and 1.5 m although a deeper installation is possible.

BENEFITS

• Increases the load-bearing capacity of soft soils even under heavy loads.

• Installation is also possible without a load distribution layer.

• Reduces the supporting moments in the plate and eliminates the risk of damaging the concrete columns.

• Requires little soil extraction and thus reduces spoils.