Vibro-Concrete Columns

Technology Overview

VCC

Vibro-Concrete Columns (VCC) were first developed in Europe in 1976 as an alternative to stone columns when the soil surrounding the column is very soft and compressible. Since stone columns derive their strength and settlement characteristics from the surrounding soil, they do not perform well in very soft clay or peat. VCC were developed to treat these soils. Instead of feeding stone to the tip of the vibrator, concrete is pumped through an auxiliary tube to the bottom of the vibrator. As the vibrator is extracted from the ground concrete is pumped to fill the void, creating a concrete column.

VCCs have been used as the column of choice on numerous column supported embankments projects throughout the United States. The columns can be installed rapidly through soft soil deposits to depths of 70 feet. Typical column dimensions are: 18-24 inch column diameter with a 24 - 36 inch bell at the bottom and top of the column. The structural capacity of an 18 inch diameter unreinforced column is approximately 250 kips. The design of the load carrying capacity of the columns (column soil interaction) is not well articulated. Numerous methods have been used based on both driven pile and caisson design. Typical VCC projects, however, verify the load carrying capacity of the column with pile load tests.

The Collin Group was involved with the first VCC project in the United States in 1994 and has been the design engineer of record for 1000's of VCC. We have utilized VCCs on over a dozen column supported embankment projects in the last decade.

Innovative Geotechnical Engineering

Vibro-Concrete Columns

Technology Overview