History 

The use of micropiles (mini pile, reticulated pile, etc.) started in early 1950s in Italy for underpinning applications of historic buildings damaged during World War II. Micropile technology is a reliable pile system that can withstand large capacity axial or lateral loads with minimal disturbance to the existing structures. They became very popular due to their ability to transfer loads efficiently through skin friction and due to their many installation advantages over conventional pile systems. 

General Notes 

A GEWI ^® Pile is a drilled and grouted micropile, less than 12 inches in diameter, that is centrally reinforced with either one or a group of two or three high tensile strength DYWIDAG THREADBAR ^®s. GEWI ^® Piles can carry loads up to 300 tons in compression or tension in relatively small boreholes.

The GEWI ^® Pile is also a friction pile. The load is transferred by bond from the THREADBAR ^® to a cement grout body and from there by friction to the surrounding ground. The friction value between grout-ground can be increased by use of post grouting techniques. 

Applications 

GEWI ^® Pile applications are influenced by the existing environment and soil conditions and methods of construction. There are two major applications that can be classified.

1. Structural support, directly loaded pile (used most often)

• Underpinning of existing structures (repair or replacement)
• Seismic retrofitting
• New foundations

2. Insitu reinforcement

• Slope stabilization and earth retension
• Settlement reduction. 

Soil Types 

The GEWI ^® Pile is a foundation element for any ground condition:

• Cohesive Soils:
  For example, clays, silts (up to an untrained shear strength of Cu >= 1.45psi) do not require additional lateral support.
• Noncohesive Soils:
  For example, sand and gravel
• Rock:
  Ranging from hard clays to granite, with open or closed joints and fissures.
• Permafrost:
  Easy to transport and to install. Ask for DSI grouting instructions.