building / substructure / consolidation

• primary compression: A reduction in volume of a soil mass under the action of a sustained load, due chiefly to a squeezing out of water from the voids within the mass and a transfer of the load from the soil water to the soil solids.
• primary consolidation: A reduction in volume of a soil mass under the action of a sustained load, due chiefly to a squeezing out of water from the voids within the mass and a transfer of the load from the soil water to the soil solids. Also called primary compression.
• secondary consolidation: A reduction in volume of a soil mass under the action of a sustained load, due chiefly to adjustment of the internal structure of the soil mass after most of the load has been transferred from the soil water to the soil solids.

building / substructure / excavation

• caisson: An air chamber without bottom, used in excavation through water or mood, and carrying down on its own top the beginning of a masonry foundation. 2. A recessed panel in a flat, vaulted or domed roof, which reduced weight and added a decorative element.
• rock caisson: A socked caisson having a steel H-section core within a concrete-filled pipe casing.
• socketed caisson: A caisson that is drilled into a stratum of solid rock rather than belled.

building / substructure / footing

• basing: Also see footing.
• footing: An enlargement at the base of a foundation wall or pier; its function is to transmit the superimposed load to the soil below. A footing is generally made of concrete, but may also be made of timber, iron, or large flat stones. Note that the pile foundation – a pile is a long wood or metal beam driven into the ground – is friction-supported and therefore requires no footing.
• footing stone: Any stone intended for the construction of a footing; especially, a broad, flat stone for forming the base course of a foundation.
• footings: Projecting courses at the bottom of a wall or pier: those below walls are continuous footings, and single-column footings are those under point-loads such as columns or piers. Footings, being wider than the walls or piers, distribute the loads.
• isolated footing: A single spread footing supporting a freestanding column or pier.
• spread footing: Truncated pyramidal structure under a pier which spreads the load rather than having it in one place. Such footings, in section like a truncated triangle, can be used under walls.
• stepped footing: A continuous or strip footing that changes levels in stages to accommodate a sloping site or bearing stratum.
• strip footing: The continuous spread footing of a foundation wall.

building / substructure / foundation

• allowable bearing capacity: The maximum unit pressure a foundation is permitted to impose vertically or laterally on a supporting soil mass. Allowable bearing pressures for various soil classifications are conservative values permitted by building codes in the absence of geotechnical investigation and testing of the soil.
• allowable bearing pressure: The maximum unit pressure a foundation is permitted to impose vertically or laterally on a supporting soil mass. Allowable bearing pressures for various soil classifications are conservative values permitted by building codes in the absence of geotechnical investigation and testing of the soil. Also called allowable bearing capacity, allowable soil pressure.
• blind area: An area covered and concealed and intended merely to keep the foundation walls dry and free from the soil. In British usage, differing from an Area Drain (which see) in having solid cross walls, and being commonly covered.
• brick fender: A brick foundation wall to support a hearth at the lowest story of a house.
• brick masonry foundation wall: Brick wall that encloses a basement or crawl space and supports the parts of the building that are above grade.
• caisson foundation: From French, caisse, “box.” A technique for constructing deep foundations in loose, saturated soils, developed in the United States, 1865-90. An open-bottom air-tight chamber is lowered into the soil and the earth is excavated from beneath it by workmen called “sand hogs.” As the chamber descends, the air pressure inside the chamber is increased to match the water pressure outside; meanwhile the hole left above is lined or filled with stones or concrete. When dense soils or solid rock is reached, the chamber is filled with concrete.
• deep foundation: A foundation system that extends down through unsuitable soil to transfer building loads to a more appropriate bearing stratum well below the superstructure.
• differential settlement: The relative movement of different parts of a structure caused by uneven settlement or failure of its foundation. Overlapping soil stresses may be caused by closely spaced footings or by adjacent footings located at different levels.
• dodai: In traditional Japanese architecture, the foundation sill (wooden) of a house.
• dodai-ishi: In traditional Japanese architecture, a foundation stone of a house.
• floating foundation: A foundation used in yielding soil, having for its footing a raft placed deep enough that the weight of the excavated soil is equal to or greater than the weight of the construction supported.
• foundation: The part of a structure that is in direct contact with the ground and serves to transmit the load of the structure to the earth; the substructure of a building (consisting of the foundation walls and footing).
• foundation investigation: The investigation and classification of a foundation soil based on observation and tests of material disclosed by borings or excavations to obtain the information necessary for the design of a foundation system, including the shearing strength, compressibility, cohesion, expansiveness, permeability, and moisture content of the soil, the elevation of the water table, and the anticipated total and differential settlement. Also called subsurface investigation.
• foundation stone: Also see cornerstone.
• foundation wall: A wall occurring below the floor nearest grade, designed to support and anchor the superstructure.
• foundation walls: Poured concrete, concrete block, brick, or rubble masonry walls that enclose a basement or crawl space and support the parts of a building that are above grade.
• grillage: A foundation mat of beams crossed and perhaps recrossed, often embedded in concrete.
• mat: A grid of reinforcement for foundation concrete.
• pier: A vertical structural support of a building, usually rectangular. 2. A cast-in-place concrete foundation formed by boring with a large auger or excavating by hand a shaft in the earth to a suitable bearing stratum and filling the shaft with concrete.
• pier foundation: Consists of piers resting on footings and supporting grade beams (upon which the superstructure is built).
• post and pier foundation: Rows of wood and concrete piers, spaced at appropriate intervals, support beams which form a base for the superstructure.
• poured concrete foundation wall: Poured concrete walls that enclose a basement or crawl space and support the parts of a building that are above grade.
• raft foundation: A foundation type developed in Chicago in the 1870s in which beams of either wood or steel are laid crosswise over piles and encased in concrete to form a pad for the base of a structural pier or column.
• ribbed mat: A mat foundation reinforced by a grid of ribs above or below the slab.
• sand foundation: A platform or bed of sand, natural or artificial, prepared for the erection of a building.
• settlement: The failure of the soil to hold a structure’s foundations where first located, or uneven failure in compression by members in the structure itself.
• shallow foundation: A foundation system placed directly below the lowest part of a substructure and transferring building loads directly to the supporting soil by vertical pressure.
• slab foundation: Poured concrete walls that enclose a basement or crawl space and support the parts of a building that are above grade.
• slab on grade: A concrete slab placed over a dense or compacted base and supported directly by the ground, usually reinforced with welded wire fabric or a grid of reinforcing bars to control any cracking caused by drying shrinkage or thermal stresses. Separate or integral footings are required for heavy or concentrated loads. Over problem soils, the slab must be designed as a mat or raft foundation.
• slab-on-grade foundation: A foundation which consists of a poured concrete slab.
• slab-on-ground foundation: A foundation which consists of a poured concrete slab.
• spread foundation: For a column or pier load, a foundation built like a pyramid to spread the weight over a large area. In soft soils, a spread foundation may be built over a cluster of piles. Spread foundations can be extended in a line for wall loads.
• substrate: Something that underlies or serves as a base or foundation.
• substratum: Something that underlies or serves as a base or foundation. Also called substrate.
• substruction: Foundation or structure below grade or below some arbitrary line, above which is the superstructure.
• substructure: Foundation or structure below grade or below some arbitrary line, above which is the superstructure.
• underpinning: The system of supports, such as rough walls or piers, beneath the ground floor. Also, the replacing or rebuilding of an infirm or old foundation so as to provide improved support.

building / substructure / freeze

• frost boil: A softening of soil resulting from the thawing of frozen groundwater.
• frost heave: An uplift in soil caused by the freezing of internal moisture.
• frostline: The maximum depth at which soil is frozen or frost penetrates the ground.

building / substructure / pile

• allowable pile load: The maximum axial and lateral loads permitted on a pile, as determined by a dynamic pile formula, a static load test, or a geotechnical investigation of the foundation soil.
• anvil: The component of a pile hammer, located just below the ram, that transfers the driving force to the pile head.
• batter pile: A pile driven at a specified angle to the vertical in order to provide resistance against lateral forces.
• bearing stratum: A stratum of soil or rock on which a footing bears, or to which a building load is transferred by a pile or caisson.
• broom: To spread out in broom shape through separation of the fibers, as when a pile is partly crushed at its head under the blows of the pile driver.
• bulb: A bulge cast or formed at the bottom of a cast-in-place concrete pile to enlarge its bearing area and strengthen the bearing stratum by compression. 2. The glass housing of an incandescent lamp, filled with an inert gas mixture, usually of argon and nitrogen, to retard evaporation of the filament, its shape is designated by a letter, followed by a number that indicates the lamp diameter.
• cased pile: A concrete pile constructed by driving a steel pipe or casing into the ground until it meets the required resistance and then filling it with concrete.
• cast-in-place concrete pile: A pile constructed by placing concrete into a shaft in the ground.
• composite pile: A pile constructed of two materials, as a timber pile having a concrete upper section to prevent the portion of the pile above the water table from deteriorating.
• cushion block: A cap for protecting a pile head as well as the pile hammer during a driving operation.
• cushion head: A cap for protecting a pile head as well as the pile hammer during a driving operation.
• drive band: A steel band encircling the head of a timber pile to prevent it from splitting when driven. Also called pile ring.
• drive shoe: The hard, pointed or rounded foot of a pile or caisson for piercing underlying soil.
• dynamic pile formula: Any of several formulas by which the allowable axial load on a pile can be calculated from the energy required for a pile hammer to advance the pile foot a specified distance into the subsoil.
• end-bearing pile: A pile depending principally on the bearing resistance of soil or rock beneath its foot for support. The surrounding soil mass provides a degree of lateral stability for the long compression member. Also called point-bearing pile.
• friction pile: A pile depending principally on the frictional resistance of surrounding earth for support.
• H-pile: A steel H-section driven as a pile, sometimes encased in concrete to a point below the water table to prevent corrosion. H-sections can be welded together in the driving process to form any length of pile.
• negative friction: An additional load on a pile resulting from settling of fill, which tends to drag the pile downward into the soil.
• pedestal pile: A cast-in-place concrete pile having an enlarged foot to increase its bearing area and strengthen the bearing stratum by compression, formed by forcing concrete out at the bottom of the casing into the surrounding soil.
• pile: An uncommon reference to the depth (front to back) of a house; a double-pile house is two rooms deep. 2. A wood or metal shaft driven into the ground as part of a foundation. 3. The upright tufts of yarn forming the surface of a carpet or fabric.
• pile cap: A reinforced concrete slab or mat joining the heads of a cluster of piers to distribute the load from a column or grade beam equally among the piles.
• pile driver: A machine by which a heavy weight is raised to a height and then allowed to fall suddenly. The windlass may be turned by hand, or by a small steam engine; the weight or hammer is commonly released by the automatic action of a hook which is thrown out of a ring when it reaches a certain height.
• pile eccentricity: The deviation of a pile from its plan location or from the vertical, resulting in a reduction of its allowable load.
• pile foundation: An enlargement at the base of a foundation wall or pier. A pile is a long wood or metal beam driven in to the ground. Friction supported and therefore requires not footing.
• pile ring: A steel band encircling the head of a timber pile to prevent it from splitting when driven.
• pile tolerance: The permitted deviation of a pile from the vertical, for which a reduction in allowable load is not required.
• pile weight: The average weight of pile yarn in a carpet, stated in ounces per square yard.
• piles: From Middle English and Latin pilum, “spear.” A heavy wooden timber or shaft of metal or concrete driven into the earth as a support for a foundation. Groups of piles may be driven in a close pattern to support a spread or raft foundation.
• piling: Made of timber, steel, or concrete, are often used where a structure is built on marshy ground.
• pilings: Made of timber, steel, or concrete, are often used where a structure is built on marshy ground.
• pipe pile: A heavy steel pipe driven with the lower end either open or closed by a heavy steel plate or point and filled with concrete. An open-ended pipe pile requires inspection and excavation before being filled with concrete.
• point of refusal: The point at which no additional settlement takes place after a pile has been loaded continuously for a specified period of time.
• point of resistance: The point at which a pile load causes a specified net settlement after being applied continuously for a specified period of time.
• point-bearing pile: A pile depending principally on the bearing resistance of soil or rock beneath its foot for support. The surrounding soil mass provides a degree of lateral stability for the long compression member.
• precast concrete pile: A precast, often prestressed concrete column, having a round, square, or polygonal section and sometimes an open core, driven into the earth by a pile driver until it meets the required resistance.
• pressure bulb: A zone in a loaded soil mass bounded by an arbitrarily selected isobar of stress, as from a single or a number of friction piles.
• pug pile: A series of accurately cut and squared timbers – generally broad and thin, as planks – drive in close contact, as for forming a temporary wall about a deep excavation… The form known as the pug pile has a tongue and groove of dovetail section by which it is tightly locked to its neighbors.
• ram: A large weight for driving piles and the like. 2. A machine for raising water.
• sand pile: A base for a footing in soft soil, made by compacting sand in a cavity left by a timber pile.
• sheath pile: Any of a number of timber, steel, or precast concrete planks driven vertically side by side to retain earth or prevent water from seeping into an excavation. Also called sheath pile.
• sheet pile: Any of a number of timber, steel, or precast concrete planks driven vertically side by side to retain earth or prevent water from seeping into an excavation. Also called sheath pile.
• skin friction: The friction developed between the sides of a pile and the soil into which the pile is driven, limited by the adhesion of soil to the pile sides and the shear strength of the surrounding soil mass.
• soldier pile: A steel H-section driven vertically into the ground to support horizontal sheeting or lagging. Also called soldier beam.
• spile: The term used in some localities to designate a pile, a columnar support driven into the ground.
• starling: A breakwater formed of piles driven closely side by side as a protection in hydraulic constructions. 2. One of the piles so used.
• sterling: Same as starling.
• stilt: One of several piles or posts for supporting a structure above the surface of land or water.
• stilts: One of several piles or posts for supporting a structure above the surface of land or water.
• sublica: In ancient construction, a pile driven into the earth, or into ground covered by water, to support a structure.
• timber pile: A log driven usually as a friction pile, often fitted with a steel shoe and a drive band to prevent it from splitting or shattering.
• uncased pile: A concrete pile constructed by driving a concrete plug into the ground along with a steel casing until it meets the required resistance, and then ramming concrete into place as the casing is withdrawn.
• yield point: The stress beyond which a marked increase in strain occurs in a material without a concurrent increase in stress. Many materials do not have clearly defined yield points. For these materials, a theoretical yield strength is calculated from the stress-strain curve. 2. The point at which an increase in pile load produces a disproportionate increase in settlement.

building / substructure / podium

• hypobasis: The lower base or the lower-most division of a base. 2. A lower base which is below a more important one.
• hypopodium: Also see hypobasis.

building / substructure / pressure

• active earth pressure: The horizontal component of pressure that a soil mass exerts on a vertical retaining structure.
• allowable soil pressure: The maximum unit pressure a foundation is permitted to impose vertically or laterally on a supporting soil mass. Allowable bearing pressures for various soil classifications are conservative values permitted by building codes in the absence of geotechnical investigation and testing of the soil.
• arching: The transfer of stress from a yielding part of a soil mass to adjoining less-yielding or restrained parts of the mass. 2. A system of arches. 3. The arched part of a structure.
• contact pressure: The actual pressure developed between a footing and the supporting soil mass, equal to the quotient of the magnitude of the forces transmitted and the area of contact.
• critical height: The maximum height at which a vertical cut in a cohesive soil wills stand without shoring.
• passive earth pressure: The horizontal component of resistance developed by a soil mass against the horizontal movement of a vertical structure through the soil.
• soil pressure: The actual pressure developed between a footing and the supporting soil mass, equal to the quotient of the magnitude of the forces transmitted and the area of contact. Also called contact pressure.
• soil structure: The arrangement and aggregation of soil particles in a soil mass.

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