STELCOR


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  • Vibrationless installation causes no disruption to the surrounding properties
  • No soil is removed during installation
  • No spoils or cross contamination
  • No removal costs or environmental concerns
  • Can be installed in high water tables
  • Positive grout displacement
  • Higher capacities for comparable cross sectional area of steel and grout
  • Minimal mobilization and demobilization costs
  • Lower cost per KIP of support compared to most other pile types
  • Exceptional lateral capacity
  • Predictable grout volumes and placement (unlike other grouted systems)

           STELCOR CASE STUDIES      

STELCOR DESIGN SPECIFICATIONS AND GUIDELINES

 

TECHNICAL EXPLANATION

STELCOR Drilled-In Displacement Micropiles are installed using hydraulic powered rotary equipment and are turned into the ground while crowd or downward pressure is exerted on the steel core and a continuous flow of grout is provided to the top of the pile. Reverse grout flow flighting welded to the steel core draws the grout into the annulus created by a displacement head located near the tip of the steel core.

The welded reverse  flighting ensures a continuous grout column and structural load transfer from the grout column into the 55 to 80 ksi steel core.

Grout ports in the steel core also provide consistent grout placement along the length of the pile.

No soil is removed during installation of STELCOR Drilled-In Displacement Micropiles and a new steel core is installed and left in the ground for every pile.

The STELCOR displacement lead section includes a helicoidal driving plate, a lateral displacement plate and a secondary deformation structure.

The driving plate helps advance the pile downward and provides end bearing support.

The lateral displacement plate creates a positive annulus around the steel core by displacing the soil outward, enhancing the density surrounding the pile element.

The secondary deformation structure produces a ribbed or corrugation effect along the grouted pile shaft, greatly enhancing soil bond and load transfer.

A continuous grout column is thereby created by means of the STELCOR displacement lead section and reverse grout flow flighting. The steel structural core extends the entire length of the pile ensuring unbroken structural integrity.

ADVANTAGES OF STELCOR

  • Vibration less installation causes no disruption to the surrounding properties
  • No soil is removed during installation
  • No spoils or cross contamination
  • No removal costs or environmental concerns
  • Can be installed in high water tables
  • Positive grout displacement
  • Higher capacities for comparable cross sectional area of steel and grout
  • Minimal mobilization and demobilization costs
  • Lower cost per KIP of support compared to most other pile types
  • Exceptional lateral capacity
  • Predictable grout volumes and placement (unlike other grouted systems)

APPLICATIONS FOR STELCOR

STELCOR is the perfect solution for achieving high axial load capacities in extremely poor soils at very shallow depths.  Where other piles fail to perform, STELCOR has delivered higher than expected load test results in both compression and tension, time after time.

The STELCOR pile takes advantage of the strengths of steel and grout, uses relatively small installation equipment, produces no spoils and consistently produces better results than were projected in design.  The load bearing soil is displaced and not removed so the end result is greater loads at lesser depths.  The STELCOR pile is also integrated into this improved soil with a unique corrugated weave of grout which greatly enhances the friction coefficient.

From structural, geotechnical, mechanical, and installation standpoints, STELCOR just makes sense, and the load test results prove it.

INSTALLATION SEQUENCE AND GROUT TAKE ESTIMATION FOR STELCOR

PART 1. GENERAL DESCRIPTION

DDM’s are installed using hydraulic powered rotary equipment and are turned into the ground while crowd or downward pressure is exerted on the steel core and a continuous flow of grout is provided to the top of the pile. A reverse flighting welded to the steel shaft draws the grout into the annulus created by a displacement head located near the tip of the steel core.

 

 

PART 2 . INSTALLATION SEQUENCE

  1. Attach the hydraulic drive head to the DDM lead section and align pile tip at specified pile location.
  2. Advanced the lead section 12 in. below ground and lift up, removing soil, to create a grout reservoir.
  3. As the lead section advances beyond the grout reservoir, commence grout flow. Monitor and record grout take during entire installation of each pile.
  4. Grout shall flow continuously to fill the annulus created by the DDM displacement head. Maintain grout level between ground level and -24 in. throughout installation.
  5. Where extensions are required, stop the drive head and remove from lead section.
  6. Attach the hydraulic drive head to a DDM extension section.
  7. Attach the extension section to the lead section with specified hardware and continue installation. Add extensions as required to reach design depth.
  8. If dense soils or obstructions are encountered and the pile will not advance, reverse the pile 24 in. and advance again. Repeat 3 – 5 times while measuring how much the pile advances each time. Do not exceed maximum specified torque of the shaft. If the pile will not advance, then pre-auguring may be required to reach design depth. Consult with Ideal to determine if the pile can be terminated in dense layers above design depth.
  9. If the pile top is terminated above the pile cut-off elevation, cut the steel core using an appropriate method such as a portable band saw or torch.
  10. Upon completion of pile installation, finish grouting to ensure that the grout level is brought to the top of pile (inside and outside of the steel core).
  11. Install the specified pile cap (or rebar) before grout sets. Bolt on caps may be installed at a later date if required.
  12. Document installation torque every 5’ during installation and at pile termination. Pile capacity is not determined by installation torque and data is used as reference only.

PART 3. GROUT TAKE APPROXIMATIONS

This calculation was made using recommended grout mix of 1- 94lb. bag of type 1 or 2 Portland cement to 5 gallons of potable water. A colloidal mixer shall be used.

  • STELCOR 1100 – 3.5 lineal ft. per bag
  • STELCOR 1200 – 3 lineal ft. per bag
  • STELCOR 1400 – 2.6 lineal ft. per bag
  • STELCOR 1600 – 1.7 lineal ft. per bag

NOTE: installer is responsible to use retardants and antifreeze as needed.