Engineering

Grip-Tite® Helical Pier System and New Construction Pier System

Shifting and unstable soils jeopardize the structural integrity of a foundation, whether it is new construction or an existing building. The Grip-Tite^® Helical Pier System is installed to effectively stabilize a foundation utilizing a steel foundation bracket to transfer the building load from the foundation, through the pier, to competent soil strata.

The Grip-Tite^® Helical Pier System significantly reduces potential total and differential settlement as compared to shallow spread footings bearing on soft or variable soils.

Installation of the Grip-Tite^® New Construction Pier System is quick, vibration-free (unlike traditional driven piles), does not generate spoils, and is cost-competitive versus over-sized engineered concrete footings and other deep foundation alternatives.

Advantages

Retrofit

• Lead sections of pier can be configured to achieve design depths and capacities
• Minimal excavation required around foundation area
• Installs quickly with small or handheld equipment
• Vibration-free installation (unlike traditional driven piles)
• No wait – piers installed year-round
• Installs in areas with limited or tight access without generating spoils
• Pier system installed below grade – not visible once installation is complete
• Cost-effective – gets a structure back on solid ground
• Permanent solution – prevents further vertical movement

New Construction

• All-weather installation
• Can be installed with either handheld or small equipment
• Can be installed in areas of limited or tight access
• Foundation concrete can be poured immediately following installation
• Lead sections can be configured to achieve design depth and capacity
• Cost-competitive versus other deep foundation alternatives
• Vibration-free installation (unlike traditional driven piles)
• Installs quickly without generating spoils

Example Model Performance Specifications

Features

• Lead sections and extensions can be configured to achieve design depth and capacity
• Lead sections available in 2, 5 and 7-foot lengths
• Extensions available in 3, 5 and 7-foot lengths
• Extensions utilize rigid, three-bolt couplings
• Helical piers available with single, double and triple helix lead sections
• Helix blade diameters of 8, 10, 12 and 14 inches
• Available with hot-dipped galvanized coating for added corrosion resistance

Specifications

Helical Pier/Anchor Tube

• Allowable axial capacity (mechanical) = 43 kips (compression), 36 kips (tension).
• 2.875-inch Outside Diameter (O.D.) x 0.262-inch wall tube steel.
• ASTM A500, Grade B&C.
  Minimum yield strength = 50,000 psi, minimum tensile strength = 58,000 psi.
• Torque Strength Rating = 11,000 ft.-lbs.  Recommended Torque Rating = 9,600 ft-lbs. 
• Compression Torque Correlation Factor (Kt) = 9 ft^-1.
• Tension Torque Correlation Factor (Kt) = 7 ft^-1

• Connecting Bolts
  0.75-inch diameter Heavy Hex Machine Bolt ASTM A490, (SAE J429 – Grade 8 Zinc Plated). 
  Minimum yield strength = 130,000 psi, minimum tensile strength = 150,000 psi.
• 0.75-inch Heavy Hex Nut, ASTM A-563, Zinc Plated.

• Weld
  ER70S-3 – minimum tensile strength = 72,000 psi.
   
• Ultimate axial capacity based upon installation torque = 85 kips (tension/compression).
• Allowable axial capacity based upon installation torque = 43 kips (FS = 2).
• Allowable capacity with retrofit foundation bracket = 30 kips.

New Construction Bracket

• 3.5-inch O.D. x 0.300-inch wall (ASTM A500, Grade C).
• 4.0 inches x 8 inches x 1-inch thick plate steel (ASTM A-36).
  
   
• Connecting Bolts
  0.75-inch diameter Heavy Hex Machine Bolt (SAE J429 – Grade 8 Zinc Plated). 
  Minimum yield strength = 130,000 psi, minimum tensile strength = 150,000 psi.
• 0.75-inch Heavy Hex Nut, ASTM A-563, Zinc Plated.

• Weld
  ER70S-3 – minimum tensile strength = 72,000 psi.
   

Retrofit Foundation Bracket

• Bracket Tube
  3.875-inch O.D. x 3.125-inch Inside Diameter (I.D.) x 10-inch long DOM mechanical steel tubing conforming to ASTM 513 – Type 5 / Grade 1026.
  Minimum yield strength = 70,000 psi, minimum tensile strength = 90,000 psi.
  
   
• Angle Bracket
  0.5-inch thick flat plate conforming to ASTM A-36 hot rolled steel bent to form a 90 degree angle with equal sides of approximately 8 inches.
  Minimum yield strength = 36,000 psi, minimum tensile strength = 58,000 psi.
  
   
• Top Plate
  0.75-inch thick x 5.5 inches wide x 9.5 inches long conforming to ASTM A-36 hot rolled steel. Minimum yield strength = 36,000 psi, minimum tensile strength = 58,000 psi.
  
   
• Cap Plate
  1.0-inch thick x 4.0 inches wide x 8.5 inches long conforming to ASTM A-36 hot rolled steel. Minimum yield strength = 36,000 psi, minimum tensile strength = 58,000 psi.
  
   
• Weld
  ER70S-3, minimum tensile strength = 72,000 psi.
  
   
• Threaded Rod
  0.75-inch diameter x 12 inches long ASTM A311 – Class B / Grade 8 Zinc Plated.
  Minimum yield strength = 115,000 psi, minimum Grade 7 tensile strength = 133,000 psi.
• 0.75-inch Heavy Hex Nut, ASTM A-563, Zinc Plated.