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Glossary of Piledriving and Foundation Construction Terms

Welcome to the APE Gloassary for piledriving and foundation construction terms. This is a great place to look for terms that you may be unfamiliar with when working with or researching piledriving technologies. This glossary also contains terms unrelated to piledriving, but that are frequently used on and around foundation construction projects. If you have a question or have term that you would like to add and do not know who to call please contact the APE Headquarters in Washington at (800) 248-8498. Business hours are from 8:00 AM to 5:00 PM Pacific Time. For less immediate inquiries, or if you would like an APE sales representitive to get in contact with you, please visit the APE Contact Request Form.

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Letter H

H-Beam See Steel H-Pile.
H-Beam Lead See Spud Lead.
H-Pile See Steel H-Pile.
Hairpin Hammer A lightweight hammer, resembling a clothespin or hairpin, dropped by gravity to tap the pile down while setting the pile line. Also to tap sheets down that are hung up in the interlocks before reaching the template.
Hairpin Lead A structure in which a pile hammer is mounted to adapt it to box leads with rails spaced wider than the hammer width. See Telescope Lead. Also called Pony Lead or Sled.
Hairpin: A gravity hammer in the shape of an inverted "U" used without leads to start sheet piles into the ground. Sometimes called pants.
Hammer Cage See Hairpin Lead, Offshore Lead.
Hammer Cushion See Pile Cushion.
Hammer Efficiency The ratio of kinetic energy of the ram immediately prior to impact divided by the rated energy.
Hammer Energy See Energy, Impact; Energy, Rated.
Hammer Grab A heavy tool used in breaking and removing obstructions in large diameter caissons or other excavations.
Hammer Line The wire rope line of the crane assigned to raising and lowering the hammer.
Hammer Speed The number of complete strokes of a pile hammer achieved by the ram per minute.
Hammer Uplift See Cylinder Lift.
Hand Spike A short slender pole used to position and hole a pile in the leads.
Handling Holes Hole or holes located near the ends of each piece of sheet piling, and used to facilitate handling procedures during installation.
Hanging Leads See Leads, Swinging.
Hard-Bite Proprietary cast-steel driving tip with cutting "teeth" for H-piles.
Hardpan 1. Most commonly a very dense heterogeneous mass of clay, sand and gravel of glacial drift of glacial origin.
2. The hard stratum of consolodated earth underlying surface soil, too hard for roots to penetrate.
Hawser A very large soft line, 1 1/2" or larger in diameter used for towing or mooring. It is generally used to refer to all three strand right lay rope.
Hay Donnage or timber used to stack rows or layers ofpiling, lumber, or other building materials. (aka Chocks)
Head 1. Shortened form of the phrase pressure head, referring to the pressure resulting from a column of water or elevated supply of water.
2. The top of the pile.
Head Block Top section of a fixed, semi-fixed or extended pile driver lead with sheaves for carrying lines holding pile and hammer over top of leads. Also called Cross Head, Sheave Head Assembly and Top Head.
Heave 1. The uplifting of earth between or near piles, caused by the displacement of soil by pile driving.
2. The uplift of a previously driven pile caused by the driving of an adjacent pile.
3. The upward movement of soil and/or foundations supported on soil, caused by expansion occurring in the soil as a result of such factors as freezing and swlling due to increased water content or sulphite soils exposed to air.
4. Frost heave refers to the vertical soil movement which occurs in freezing temperatures as ive layers or lenses form within the freezing soila nd cause the soil mass to expand. See also Bottom Heave.
Heaving The uplifting of the earth between or near pile, caused by soil displacement from driving piles, the uplift of an in place pile caused by the driving of an adjacent pile. Can also be caused by freezing and thawing.
Helical Binders Mild steel rods spirally arranged about the main reinforcement steel to bind the latter to form a cage.
Helical Shell Corrugated (usually 12 to 18 gauge) steel rolled into a sprial pipe with the joint crimped or welded watertight. The shell is installed as a pile with a mandrel.
Helix Rebar bent to form a spiral shape. Used to reinforce concrete columns.
Helmet See Drive cap, generally refers to cast steel component only.
Hickey Bar A tool used for bending re-bar or conduit.
High Chair A heavy wire device used to support and hold reinforcing steel in place in the form.
Hiley Formula A dynamic pile driving formula for estimating the static load bearing capacity of a pile driven from its penetration resistance. It includes terms for pile weight to ram-weight ratio, pile rebound, and cushion properties.
Hitch A knot that secures a rope to a post, ring, spar or rail, etc., or to another rope which takes no part in tying the knot. It won't keep its shape on its own. In climbers jargon, a "hitch" is often just a temporary fastening.
Hoisting Engine A prime mover and a hoist with one or more drums mounted on a common sled base.
Holding Bolts Used to connect wales or walers to pilings.
Hollow-Stem Auger An earth auger with an end bit on a hollow center shaft. See Auger.
Home, Pile A point at which a pile has reached specified soil penetration and/or blow count.
HorsenSchitz What you say when you catch someone trying to use good ol' American traditions like home cooking and apple pie to sell products made in Germany. See also BullzenSchitz.
Hospital Side A colloquial expression indicating the side of the pile driver which is the most dangerous.
House The structure on a crane that covers the mechanical parts, motor, brakes, frictions, and drums. Also a term "let's head for the house" meaning "let's go home".
Hydraulic Collapse The hydrostatic pressure in the ground (usually below a clay strata) which will cause the collapse of thin pile casing.
Hydraulic Fill Earth fill moved and placed by pumping with water.

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