Vibro concrete columns involve constructing concrete columns with a bottom-feed, down-hole vibratory probe to transfer loads through weak strata to a firm underlying stratum.
Process
A bottom-feed, down-hole vibratory probe is advanced through the weak strata to the underlying firm stratum. The vibrator densifies granular-bearing soils. Concrete is then pumped through the bottom-feed tremie tube. The vibrator is raised and lowered within the bearing depth several times to construct an expanded base. The vibrator is then raised to the surface as concrete fills the void created by the vibrator during extraction. Typically, the vibrator also re-penetrates the top of the column to construct an enlarged head, which a geogrid-reinforced soil-relieving platform can overlie.
Common uses
- Reduce foundation settlement
- Increase bearing capacity, allowing reduced footing size
- Increase stiffness
- Increase shear strength
- Reduce permeability
- Mitigate potential for liquefaction
- Provide slope stabilization
Advantages
- A versatile ground improvement method that adjusts to a variety of soil conditions and foundation requirements
- Offers an economical solution for ground improvement
- Can be carried out to almost any depth
- Relatively quick execution so subsequent structural works can follow quickly
- Soil improvement enables standard shallow footings, which can lead to savings
- Extremely quiet with low vibration
- A small quantity of soil has to be removed so it avoids the cost of spoil removal associated with continuous flight auger and bored piling systems
Quality assurance
Vibro rigs can be fully instrumented with an onboard data acquisition system. Data from the system, such as amperage and lift rate, can then be recorded and displayed in real time alongside specified target values on an in-cab monitor. This monitoring allows the operator to correct any deviations in real-time during the construction process to keep the vibro compaction within project specifications.real time
Related techniques
Related solutions
Related projects
Oil, gas and chemical
Elkhorn Valley Ethanol
Keller provided a cost-effective vibro concrete columns design to overcome constructability concerns (necking) within the soft soils.
Residential
Society Hill Apartments
Keller's alternate vibro concrete column proposal alleviated concerns regarding contaminated groundwater percolating up through the originally proposed timber pile foundations into the clean fill below the housing units.
