Stelcor®


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  • Stelcore’s vibration-free installation causes no disruption to the surrounding properties.
  • No soil is removed during installation.
  • There are no spoils created and cross contamination.
  • There are no removal costs or environmental concerns.
  • Stelcore can be installed in high water tables.
  • Stelcore has positive grout displacement.
  • Stelcore micropiles have higher capacities for comparable cross sectional areas of steel and grout.
  • There are minimal mobilization and demobilization costs.
  • There’s a lower cost per KIP of support compared to most other pile types.
  • Stelcore micropiles have exceptional lateral capacity.
  • Stelcore micropiles utilize 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. Meanwhile, 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-free installation causes no disruption to the surrounding properties.
  • No soil is removed during installation.
  • There are no spoils or cross contaminations.
  • There are no removal costs or environmental concerns.
  • Stelcor piles can be installed in high water tables.
  • Stelcor piles provide positive grout displacement.
  • Stelcor provides higher capacities for comparable cross sectional areas of steel and grout.
  • There are minimal mobilization and demobilization costs.
  • There is a lower cost per KIP of support compared to most other pile types.
  • Stelcor offers exceptional lateral capacity.
  • This pile provides 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 shallower depths. Stelcor piles are also integrated into their 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. For more information, check out the following links:

INSTALLATION SEQUENCE AND GROUT TAKE ESTIMATION FOR STELCOR PILES

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 the pile tip at specified pile location.
  2. Advance the lead section 12 inches below ground and lift up, removing the soil, in order to create a grout reservoir.
  3. As the lead section advances beyond the grout reservoir, commence grout flow. Monitor and record grout take during the 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 the installation.
  5. Where extensions are required, stop the drive head and remove it from the 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 your designated depth.
  8. If dense soils or obstructions are encountered and the pile will not advance, reverse the pile 24 inches and advance again. Repeat three to five 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 the designated 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 feet during installation and at pile termination. Pile capacity is not determined by installation torque and data is used as a 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: The installer is responsible to use retardants and antifreeze as needed.