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a tool having a helical shaft that is used for boring holes into the ground and removing the loosened soil

Axial the direction perpendicular to the plane of the top of the pile

is a portion of a pile, which protrudes beyond the nominal diameter of the pile. This occurs when piles are bored through strata of soils with differing density. Bulging occurs when good practices are being observed.


an earthy material that is plastic when moist but hard when fired, that is composed mainly of fine particles of hydrous aluminum silicates and other minerals


is a term used to indicate that piles have been placed too close together while the concrete grout is still fluid. Visual observations of changes in levels of grout in the pile above or below the ground indicate the adjacent shaft may have expanded which may result in reduced shaft diameter of the other pile.

Compression downward vertical load on a pile
Concrete Grout a mixture of cement , water and sand or chemicals that solidify
Cores are cylindrical samples of rock which are obtained from drilling and tested for compressive strength
End Bearing the force that resists motion between the tip of the pile and the soil/rock.
Fly ash

is a residue left over from burning coal. Most fly ash is pozzolanic, which means it’s a siliceous or siliceous-and-aluminous material that reacts with calcium hydroxide to form a cement. Properly selected fly ash reacts with the lime to form CSH–the same cementing product as in portland cement. This reaction of fly ash with lime in concrete improves strength. Typically, fly ash is added to structural concrete at 15-35 percent by weight of the cement.

The most important benefit is reduced permeability to water and aggressive chemicals. Properly cured concrete made with fly ash creates a denser product because the size of the pores are reduced. This increases strength and reduces permeability. The reduced permeability helps to protect the concrete from chloride penetration, the cause of rebar corrosion (see Rosenberg’s article on corrosion in the Fall 1999 issue of MC Magazine).

Advantages in Fresh Concrete
Since fly ash particles are spherical and in the same size range as portland cement, a reduction in the amount of water needed for mixing and placing concrete can be obtained. The use of fly ash can result in better workability, pumpability, cohesiveness, ultimate strength, and durability.

Advantages in Hardened Concrete
Strength in concrete depends on many factors, the most important of which is the ratio of water to cement. Good quality fly ash generally improves workability or at least produces the same workability with less water. The reduction in water leads to improved strength.

Friction the force that resists relative motion between the surface of the pile and the contact with the soil
Geotechnical Report

a summary report of the exploration of the subsurface soils and how they are to be used as construction materials.

Group effect a group of piles under load will behave differently than individually loaded piles

is a term that normally refers to the height in feet that the concrete grout is above the tip of the auger discharge bit as it is being withdrawn from the hole. While this can’t be measured because it is below the ground it is normally estimated by observing height the grout on the auger after it is totally withdrawn from the hole.

Impenetrable incapable of being penetrated

is a geological term which describes the conditions existing in limestone formations containing solution filled cavities and voids.

Neat Line volume refers to the theoretical volume of a cylindrical shaft of a given diameter and length, and is normally expressed in Cubic Yards. It is calculated by multiplying 3.1416 (PI) times the radius squared times the length. The Neat Line volume is referred to as 100%.

is a condition most feared by engineers and designers. Should the withdrawal rate of the auger exceed the replacement rate of the concrete pumped into the pile the soil may collapse and make the pile shaft smaller than nominal. In other cases shaft could be discontinuous. This could result is serious structural inadequacies.

Negative Skin Friction

is a condition when piles are placed though compressible strata where the skin friction on the pile above the compressible layer is considered to reduce the overall load carrying capacity of the pile.


is a term that refers to the amount of concrete used in excess of the Neat Line Volume of a cylindrical shaft of a given diameter.

Overage factor

Is the Estimated Volume of Concrete pumped divided by the Neat Line Volume of the pile. Most engineers specify a minimum of 115%.


is a theoretical condition which occurs when a continuous helical auger is rotated into the ground and excessive soil is removed . It is thought that this condition may cause a reduction in the soil density and thus a reduction in available skin friction between the soils and the pile surface. Over-flighting may be considered occurring when large depressions occur around the hole while it is being installed..

Penetration the action of passing through
Pile a long slender column composed of solidified concrete grout constructed in the ground to carry a vertical load
Pile Load Test

is a test to determine the safe load carrying capacity of a pile. A load is superimposed on a pile the load deflection and given intervals are recorded and analyzed. Reaction systems for applying loads to test pile can consist of weighed blocks or anchor piles with steel beams.

Pile Caps

are steel reinforced concrete structures , normally square or rectangular, of a thickness which combine piles in groups to support singular columns above.

Positive Concrete pressure

is thought to be the pressure that is required to maintain the shaft of concrete when extracting the auger during casting of the pile. There are varying beliefs on the pressure required and where the pressure should be measured. Because there are numerous factors which affect the line pressure such as , concrete consistency, height, length of supply hoses, location of gages and pump ability, there is not a known authority on this subject.

Rock consolidated or unconsolidated solid mineral matter. The predominant rock in Florida is limestone, calcium carbonate (CaCO3).
Safety Factor

is a multiple of safety greater than 1 that is applied to the design load carrying capacity of a pile. Engineers and codes may specify the factor of safety depending on the structure that is being supported. Most codes require a safety factor of 2. This is sometimes increased depending on the amount of information available about the site.

Sand a loose granular material that results from the disintegration of rocks, consists of particles smaller than gravel but coarser than silt
Silt loose sedimentary material with particles usually 1/20 millimeter or less in diameter
Soil Test Boring a bore hole drilled or augered into the ground in which soils are sampled at intervals, obtained and classified.
Standard Penetration Test Boring

is the sampling of soils using a standard procedure in which a sampler of a given size driven into the soil with a 140 pound hammer falling from a height of 30 inches. The number of blows of the hammer is recorded for each successive 6 inches of penetration for a total of 18 inches. The total number of blows for the last 12 inches is called the “N” Value. See ASTM.

Standard Penetration Test Boring Log

The a graphical representation of the inferred subsurface soil strata recorded at depth with it’s corresponding “N” Value.

Strata soil or rock of one kind lying between beds of other kinds
Tension upward vertical load on a pile
Unified Soil Classification System is standard system of classifying soil by particle size and characteristics.
Neat Line Volume

is normally expressed in Cubic Yards. It is calculated by multiplying 3.1416 times the radius squared times the length. The Neat Line volume is referred to as 100%.

Weathered is a term that described the condition of limestone that is weakly cemented together.

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West Coast Foundation, Inc.
2400 22nd Street North
St. Petersburg, FL.  33713
Phone: (727) 823-7770 - Fax: (727) 823-5716

Email: rsmith@augercastpile.com