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.
|p.s.i.g.||Pounds per square inch pressure shown by gage at pressure boiler or air compressor.|
|Pad||See Pile Cushion.|
|Pants, Hammer||Slotted plates fastened to the sides of a pile hammer to engage the heads of template supported sheet pile, to keep the hammer centered upon and in vertical alignment with the pile to permit the hammer's operation free-hanging. Also called Fish Tails, Fingers. See Hairpin.|
|Parallelogram Brace||Proprietary brace to change pile hammer leads from side to side without use of a moonbeam.|
|PCSA||Power Crane and Shovel Association.|
|Peat||A fibrous mass of organic matter of spongy consistency.|
|Peavy||Long hangled tool similar to a cant hook but with a steel point at its end and a hinged hook for turning piles or timbers.|
|Pedestal Pile||A cast-in-place concrete end-bearing pile, frequently patented, constructed so that concrete is placed or forced out into a bulk or pedestal at the base of the pile. See Compacted Concrete Pile.|
|Peeled||A tree trunk form which all of the bark has been removed before treating and/or driving.|
|Pendulum Leads||See Leads, Swinging.|
|Penetration Resistance||1. The resistance to penetration from driving expressed in blows per increment of advance of the pile.
2. The N Value in the Standard Penetration Test.
|Penetration Test||Term generally applied to subsurface investigative methods for determining a strength-related property of a soil by measuring the resistance to advancement of the penetration of boring and/or sampling equipment. See N Value.|
|Penetration, Gross||1. The total downward movement of the pile caused by the hammer blow before rebound.
2. Maximum movement during test loading.
|Penetration, Minimum||Depth or length of pile specified to theoretically develop the required load bearing or uplift capacity of the soil, the required lateral strength or a desired bearing strata.|
|Penetration, Net||1. The gross movement of the pile less the rebound from a hammer blow.
2. Net measured settlement after unloading from a test.
|Penetrometer||A device for measuring resistance to penetration of a point, calibrated to indicate approximate load-bearing strength of the pile. Often called Dutch Cone Penetrometer.|
|Percussion Boring||A means of advancing a bore using air or cable driven impact tools or excavating tools which are repeatedly dropped onto the face or base of the bore.|
|Permafrost||Permanently frozen ground; very difficult to penetrate with piling and unstable when disturbed.|
|Permeability||The ability of water (or other fluid) to flow through a soil by traveling through the void spaces. A high permeability indicates flow will occur rapidly, and vice versa.|
|Pier||1. A structure built perpendicular or oblique to the shoreline of a body of water for mooring ships.
2. A plain, detached mass of masonry, usually serving as a support: the pier of a bridge.
3. Category applied to column-like foundations, similar to piles. The pier is generally considered the type of deep foundation which is constructed by placing concrete in a deep excavation large enough to permit manual inspection.
4. Pier is also used frequently to indicate heavy masonry column units which are used for basement-level and substructural support.
5. An upright projecting portion of a wall; a buttress.
|Pile||A structural column of timber, steel, concrete, etc., installed in the ground to resist or transfer vertical, horizontal or combination loads imposed upon it. See: End Bearing Pile, Friction Pile, Steel H-Pile, Steel Pipe Pile, Timber Pile.|
|Pile Bent||Two or more piles driven in a row transverse to the long dimension of a structure, such as a bridge foundation, and fastened together by capping and bracing.|
|Pile Buck||Colloquial term for a member of a pile crew.|
|Pile Bulkhead||See Seawall.|
|Pile Butt||1. The head of a pile (particularly for a timber pile).
2. The cut-off top of a pile.
|Pile Cap||A structural member placed upon the tops of piles to transmit and distribute the load of the structure down to the head of a pile, a row of piles, or a pile group.|
|Pile Clamps||1. Pairs of timbers bolted to the sides of the piles in a bent; steel channels bolted or welded to H-pile where they tie the piles together and also carry and distribute loads to the piles.
2. A mechanical device for gripping piles, used with vibratory hammers and extractors.
|Pile Cluster||1. A group of piles, standing free as a dolphin or as mooring piles or piles in contact forming part of a fender system for the purpose of mooring or breasting off vessels for better control. See Dolphin.
2. Group support for column loads.
|Pile Cushion||Cushion placed between drive cap and top of concrete pile to protect pile from crushing and spalling. Also called Cushion, Pad.|
|Pile Cut-Off||The length of pile removed above the cut-off elevation.|
|Pile Driver||1. A rig consisting of leads, hoisting apparatus and a pile hammer.
2. A member of the Pile crew.
|Pile Driving Cap||See Drive Cap.|
|Pile Encasement||Protective cover for steel or timber pile. This usually is concrete, added at the water or ground line, where all types of piles are most vulnerable to corrosion and insect attack.|
|Pile Extractor||A device for pulling piles out of the ground. It may be an inverted steam or air hammer with yoke so equipped as to transmit upward blows to the pile body or a specially built extractor utilizing this principle. Vibratory hammers are especially effective. All extractor operations require a strong upward force. Also called Extractor.|
|Pile Fall||See Pile Line.|
|Pile Formula||An equation from which the static resistance or the allowable load of a pile may be estimate from the driving record of the pile. See Dynamic Formula.|
|Pile Foundation||The piles and the structural members designed and installed primarily to transmit loads directly from a superstructure to the soil or rock stratum some distance below the ground surface which is capable of sustaining the load.|
|Pile Frame||See Skid Rig.|
|Pile Gate||A device at the base of the pile hammer leads, which is cloesd aruond the pile to maintain alignment between the pile and the leads.|
|Pile Hammer||General term for machine which drives piling by impact or vibration. Power source may be mechanical, air, steam, diesel or hydraulic.|
|Pile Hammer, Automatic||A power pile hammer in which the fluid valve is automatically thrown at both ends of the ram stroke to produce a regular cycle.|
|Pile Hammer, Semi-Automatic||A power pile hammer for which the valve is manually thrown at one end of the stroke and automatically thrown at the other end.|
|Pile Head||The top of the pile. See Butt Of A Pile.|
|Pile Heave||See Heave.|
|Pile Joint||Means for joining lengths of pile.
1. H: full penetration butt weld or close-fitting mechanical device plus welding across flanges and additions.
2. Pipe: Butt weld or driving into tapered circular sleeve.
3. Precast: A variety of types - matched male-female ends locked by mechanical means; drilled holes and dowels; drive sleeve similar to that for pipe.
4. Composite: joining two types of piles.
|Pile Line||A wire rope used to lift a pile and hold it while being placed in the leads; one of the hoisting lines on crane, assigned to pile handling. Also called Pile Fall.|
|Pile Load Test||See Load Test, Test Pile.|
|Pile Log||See Driving Log.|
|Pile Master||See Taywood Sheet Pile Driver/Extractor.|
|Pile Monkey||1. The workman who climbs the lead to position pile beneath the hammer.
2. The workman who sits atop a sheet pile wall and threads interlocks.
3. Trade name for a mechanical device controlled by the crane operator to accomplish the purpose of 1. above.
4. Sometimes called pile rabbit.
|Pile Penetration||1. The depth or subsurface elevation reached by the tip of the pile.
2. Embedment of the pile.
3. The set of the pile.
|Pile Point||A cast or fabricated steel drive shoe which may be pointed and its fixed to the pile shaft at the tip for easier driving, improved penetration, protection against damage in dense material or boulders and improved bearing at the tip. Also called Driving Point, Drive Shoe, P ile Shoe or Conical Point.|
|Pile Refusal||See Refusal.|
|Pile Rig||See Pile Driver.|
|Pile Ring||A metal hoop used to bind the head of a timber pile during driving to prevent splitting and brooming. Also accomplished by banding.|
|Pile Run||A sudden fast drop of a pile after a strike from the hammer. Pile run is caused by a sudden absence of pile resistance due to extremely soft soils or underground lakes or voids. Pile run also occurs when driving driving from a stiff layer to a soft layer of soil while the hammer is set to full stroke operations or, when using a vibratory pile driver/extractor, the crane operator has slacked the main line too much while the pile cuts into a voided area. The pile run can be so dramatic that the pile falls out of the drive cap and/or insert or jaws. To prevent injury or death from falling piles that suffer a sudden pile run the leads should be equipped with protective gates or rabbits to hold the pile into the leads shut pile run occur. A Pile Safety Line leading from the crane should be attached to the pile until the pile has reached a self supporting state or at least 50% of the length of the pile. See Driving Theater and Pile Safety Line.|
|Pile Safety Line||Line or cable attached to the pile and used to place pile and hold pile safely until it is driven to the point of self supporting. Also used during extraction of pile to keep crane boom from snapping back should vibratory pile driver/extractor come loose of pile during hard pulling. Pile Safety Line should be attached to all non-interlocking piles. See Driving Plan and Driving Theater.|
|Pile Set||See Set.|
|Pile Shoe||See Pile Point.|
|Pile Splicer||A close-fitting device for quickly aligning an additional length of similar or compatible sections of pile to increase length. See Spliced Pile, Composite Pile.|
|Pile Take Up||An increase in the observed resistance to penetration during driving.|
|Pile Template||A prefabricated strucutre or site-erected frame into which pile is set and held firmly in position to permit driving with a free-hanging pile hammer. Usually rectangular in form to space and position piles so that they will be in specified position relative to one another. Also called Grid.|
|Pile Tip||The bottom end of a pile. Also called Foot of a Pile.|
|Pile, Cast-In-Place Concrete||See Cast-in-place Pile.|
|Pile, Timber||A tree trunk, usually debarked, driven into the ground. It may be pressure impregnated with creosote, pentaclorophenol, or chromated copper arsenate or ammoniacal copper arsenate.|
|Piling Contractor||The contractor, frequently a subcontractor, who specializes in installing piles.|
|Pipe Lead||Lead with main member of a pipe, to which a guide is attached for the hammer to slide on. Also called Monkey Stick, Spud Lead, European Lead or Pogo Stick.|
|Pipe Pile||See Steel Pipe Pile.|
|Piston||The part of the falling weight in a power pile hammer which is fitted with piston rings. See Ram.|
|Pitching the Pile||Positioning the pile in the leads for driving. See Lofting.|
|Plasticity||Term applicable to fine-grained cohesive soils (such as clays) with the ability to flow or be remolded without raveling or breaking apart. See Atterberg Limits.|
|Plug||The soil inside a pipe pile driven open-end.|
|Plumb Pile||A vertical Pile.|
|Pogo Stick||See Pile Lead.|
|Point of Fixity||See Depth of Fixity.|
|Pore Pressure||Water pressure developed in the voids of a soil mass. Excess pore pressure refers to pressure greater than the normal hydrostatic pressure expected as a result of position below the water table.|
|Positive Batter||See Fore Batter.|
|Posttensioning||A method of prestressing a concrete member in which cables or bars are placed in ducts through the concrete member. When the concrete reaches a specified strength, the tendons are tensioned by jacking against the member and then anchored to it. See Pretensioning.|
|Power Pack||A primve mover composed of an engine and generator hydraulic pump or compressor to provide electricity, hydraulic power or air to portable construction equipment such as a vibratory extractor or auger.|
|Practical Refusal||See Refusal.|
|Pre-Excavation||1. Advance excavation of a general site.
2. Removal by augering of soil that may heave.
3. Removal of soil by driving and cleaning out an open-end pipe.
|Preaugering, Preboring or Predrilling||1. Boring through obstructions or materials too dense to penetrate with the planned pile type. This is commonly done for displacement piles in stiff clays where heave may occur.
2. Exploratory drilling to below utility lines to locate and minimize damage to unknown facilities.
|Precast Pile||A concrete pile either reinforced or prestressed which is manufactured in a construction yard or at the site, and having been properly cured, is handled and driven like a steel or timber pile.|
|Precast Segmental Pile||A precast pile manufactured in lengths which enable the pile to be extended on site relatively quickly which a mechanical splice. See Bruns Pile, Pile Splicer.|
|Pressure Grouting||See Grouting, Foundation.|
|Pressure Head||See Head.|
|Pressure Injected Footing||See Enlarged Base.|
|Pressure Meter||A device that can be lowered into a bore hole and expanded to determine the lateral resistance of the soil.|
|Pressure-Treated Pile||Round or sawn timber used as a pile, which has been pressure impregnated with a chemical preservative, e.g., creosote, pentachlorophenll, or ammoniacal copper arsenate or chromated copper arsenate.|
|Prestressed Pile||A precast concrete pile which is prestressed or posttensioned to reduce or eliminate cracking caused by tensile stresses to which piles are subjected during transportation, driving and in service.|
|Prestressing||Compressing a concrete member with tensioned cables or bars running through it to make it lighter for its strength and to counteract handling stresses.|
|Pretensioning||A method of prestressing a concrete member in which cables or rods are jacked against and then anchored to abutments in a form before the concrete is poured. When the concrete member has cured to specified strength, the tendons are detached from their anchorages and relieved of their stress. Restrained from shortening by bond with the concrete, the tendons compress the concrete member.|
|Primary Drive Cap||A drive cap that requires an adapter for different shapes of piles. It is used only with an adapter.|
|Production Pile||Pile which is part of a specified pile foundation, as opposed to a preliminary test pile.|
|Production, PIles||The number of piles which can be installed in a defined period of time (i.e., piles driven per 8 hour day).|
|Protector||A protective end reinforcement for steel sheet piling.|
|Pruyn Point||Trade name for a protective cast-steel pile point for H-pile.|
|psi, psf||Pounds per square inch (foot), the English unit of measure of pressure.|
|Puddling||A technique for achieving an uncontrolled degree of compaction of granular fill by saturating the soil after it is dumped into the excavation.|
|Pull Out Resistance||See Uplift Capacity.|