Bi-Modulus Columns (BMC)® are vertical ground improvement elements that are comprised of a Controlled Modulus Column (CMC)® rigid inclusion that is topped with a compacted granular column. By incorporating CMCs and stone columns, BMCs are designed to offer the distinct advantages of both types of vertical elements.
WHAT ARE THEY?
Robust vertical ground improvement elements with a rigid inclusion topped with a compacted granular column.
HOW DO THEY WORK?
By combining the advantages of stone columns and Controlled Modulus Column (CMC)® rigid inclusions, the upper soil becomes more compliant in areas with high seismicity, load transfer platforms (LTPs) may be reduced in thickness or eliminated, and the benefits of CMCs are realized in the deeper layers.
WHY USE THEM?
Increase bearing capacity, optimize the thickness or obviate the need for LTPs, and mitigate liquefaction in upper granular soils.
CMC installed with displacement drilling methods (left). Stone column installed on top of CMC with stone column equipment (right).
Advantages of Bi-Modulus Columns Include:
- Combines the benefits of CMCs and stone columns
- Ideal for layered sites with granular soils over compressible layers
- Reduces thickness or eliminates the need for LTP
- Mitigates upper liquefiable layers
- Simplifies challenges associated with excavating the tops of elements to accommodate the bottom of footing elevations
Download our BMB technique sheet: