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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 L

Lace 1. To raise and slip an interlock of a pile, such as a steel sheet pile, into the interlock of an adjoining pile. Also called Thread.
2. To raise and slip a pile hammer into a pile hammer leads so that its side channels properly engage to slide upon the guides of the leads.
Lacing The act of interlocking sections of sheet pile to form a wall. Also called Threading.
Lagged Pile A pile to which longitudinal pieces (lags) are fastened to provide mechanical protection to a pile or increase friction contact area. See Lags, Stoppers.
Lagging The horizontal members, usually of timber or concrete, spanning between two soldier piles. See Lags.
Lags 1. Plates, blocks or structural sections secured to a pile to increase its bearing or friction area. Also called Lagging.
2. Thin slats on creosoted piles in marinas to reduce creosote stains on boats.
Laitance A mixture of bleed water, cement and fine sand that may appear at the top of concrete after placing, especially in high lifts such as piling. It has no structural value.
Land Metal left as at a bevel on the flange of an H-Pile for back-up of a weld.
Large Diameter Pile A pile with a nominal diameter exceeding 24 in. (600 mm).
Lateral Load Horizontal component of a load on a pile.
Lateral Pressure See Earth Pressure.
Lateral Support 1. Batter piles or reinforcement to resist lateral forces on piles or footings. See Bracing.
2. Support provided by soil, which prevents column failure of a driven pile.
Layout Marking out by staking in the ground where H piles are to be placed. Marking the template with caulk or paint where each sheet pile is to be placed, so the opening where the last sheet is to go is not too wide or narrow.
Lead Column See Leads.
Lead Rails See Guides.
Lead, Cardonic A lead which is fixed to a crane normally in an extended configuration, but has three directions of freedom about the boom point (i.e., in and out, left and right, and around) rather than just in and out, left and right movement. Also called Swivel Leads.
Leaders See Leads.
Leads 1. A structure of fabricated steel or wood in which or on which a pile hammer travels up and down and with which the hammer and pile assembly is aligned in driving position.
2. A complete hammer support system including lead column, brace and other components. Also called Leaders.
Leads , Underhung Pile hammer leads which hang from the boom point pin of a crane by straps or pendant cables.
Leads, Extended Pile hammer leads which extend above and attach to the boom point of a crane. Also called Overhead Leads.
Leads, Fixed See Leads, Extended.
Leads, Free-Hanging See Leads, Swinging.
Leads, Semifixed 1. A trade name for a type of extended lead.
2. An extended pile hammer lead which may be raised or lowered independently of the boom by a cable from the crane. Also called Vertical-Travel Leads.
Leads, Swinging Pile hammer leads topped with a bail and hung from one load line of a crane. Also called Hanging Leads, Pendulum Leads.
Leads, Three-Way See Leads, Cardonic.
Leads, Vertical-Travel See Leads, Semifixed.
Levee An embankment of earth built up alogn the sides or a river to prevent its overflowing its banks.
Level Check The act of checking to see if the pile is plumb by placing a carpenter's level on the pile. Note: Piles should never be checked while the pile driver is in the act of driving or extracting the pile. Stay clear of pile driver during pile driving operations. Check plumbness only after the hammer is shut off and all dynamic activity regarding the pile hammer is static. See Compression Bounce.
Limerock A compact, high-calcium limestone originating from coral and other marine remains.
Line Oiler Lubricator insterted in pressure air or steam line to lubricate hammer. See Sight Feed Lubricator.
Liner See Casing.
Liquefaction Loss of strength occurring in saturated, fine-grained cohesionless soil when exposed to shock or vibrations when the soil particles momentarily lose contact due to pore pressure increase. The material then behaves as a fluid without shear strength. See Quicksand.
Live Boating A term used when a diver is in or underwater and the motor of the boat or barge is running and the prop is turning. A dengerous practice as he or his dive hose could become entangled in the turning of the prop.
Live Boom The boom of a crane that is controlled only by friction and brakes. They can be dangerous to work around as rain, snow, and other conditions can cause the frictions and brakes to slip and the boom to run away.
Live Hammer See Free-Hanging Hammer
Live Load A moving or non-permanent load which a structure is designed to support in addition to its own dead load.
Load Test Testing capacity and relation of load to movement by putting a load on the bearing element before actually building upon the foundation. ASTM Standard D1143 covers Method of Testing Piles.
Loam A mixture of sand, silt and clay with with generally a varying amount of organic material.
Lock Seam Longitudinal or spiral seam in corrugated or other pipe formed by overlapping or folding the adjacent edges.
Loess A wind-blown soil, generally silt, weakly cemented.
Lofting The act of raising pile into leads to place beneath hammer. Also called "pitching the pile."
Loftsman See PIle Monkey.
Log See Driving Log.
Low Displacement Pile Pile with minimal soil displacement, such as H, open-end pipe or sheet piles. Also called Non-Displacement Pile.
Lubricator See Line Oiler, Sight-Feed Lubricator.

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