DK Ching VD - Reinforced Concrete

reinforced concrete

concrete in which steel reinforcement is embedded in such a manner that the two materials act together in resisting forces; also called "beton arme", "ferroconcrete:

plain concrete

concrete having no reinforcement

ferrocement

constructed of cement-sand mortar over a wire mesh that has been preshaped over a mold

fiber-reinforced concrete

concrete reinforced with dispersed, randomly oriented fibers of glass or plastic

welded-wire fabric

a grid of longitudinal and transverse steel wires or bars welded together at all points of intersection

woven-wire fabric

a mesh of cold-drawn steel wires mechanically twisted together to form hexagonally shaped openings

reinforcement

a system of steel bars, strands, or wires for absorbing tensile, shearing, and sometimes the compressive stresses in a concrete member or structure

reinforcing bar

a steel bar for reinforcing concrete

deformed bar

a reinforcing bar hot-rolled with surface deformations to develop a greater bond with concrete

tension reinforcement

reinforcement designed to absorb tensile stresses

compression reinforcement

reinforcement designed to absorb compressive stresses

effective depth

the depth of a concrete section measured from the compression face to the centroid of the tension reinforcement

bar spacing

the center-to-center spacing of parallel reinforcing bars

cover

the amount of concrete required to protect steel reinforcement from fire and corrosion

bond

the adhesion between two substances

bond stress

the adhesive force per unit area of contact between a reinforcing bar and the surrounding concrete developed at any section of a flexural member

cracked section

a concrete section designed or analyzed on the assumption that concrete has no resistance to tensile stresses

cracking load

a load that causes the tensile stress in a concrete member to exceed the tensile strength of the concrete

effective area of concrete

the area of a concrete section between the compression face and the centroid of the tension reinforcement

effective area of reinforcement

the product of the right cross-sectional area of reinforcement and the cosine of the angle between its direction and the direction for which its effectiveness is considered

percentage reinforcement

the ratio of effective area of reinforcement to effective area of concrete at any section of a reinforced concrete member, expressed as a percentage

balanced section

a concrete section in which the tension reinforcement theoretically reaches its specified yield strength as the concrete in compression reaches its assumed ultimate strain

overreinforced section

a concrete section in which the concrete in compression reaches its assumed ultimate strain before the tension reinforcement reaches its specified yield strength; failure of the section could occur instantaneously without warning

underreinforced section

a concrete section in which the tension reinforcement reaches its specified yield strength before the concrete in compression reaches its assumed ultimate strain; failure of the section would be preceded by large deformations, giving prior warning of impending collapse

embedment length

the length of embedded reinforcement provided beyond a critical section for anchorage

hook

a bend or curve given to the end of a tension bar to develop an equivalent embedment length

standard hook

a 90d, 135d, or 180d bend made at the end of a reinforcing bar according to industry standards with a radius based on the bar diameter

anchorage

any of various means, such as embedment length or hooked bars

critical section

the section of a flexural concrete member at a point of maximum stress, a point of inflection, or a point within the span where tension bars are no longer needed to resist stress

reinforced concrete beam

a concrete beam designed to act together with longitudinal and web reinforcement in resisting applied forces

longitudinal reinforcement

reinforcement essentially parallel to the horizontal surface of a slab or to the long axis of a concrete beam or column

deep beam

a reinforced concrete beam having a depth-to-span ratio greater than 2:5 for continuous spans, or 4:5 for simple spans, subject to nonlinear distribution of stress and lateral buckling

T-beam

a monolithic reinforced concrete construction in which a portion of the slab on each side of a beam acts as a flange in resisting compressive stresses, and the portion of the beam projecting below the slab serves as a web or stem in resisting bending and shear stresses

top bar

any of the longitudinal bars serving as tension reinforcement; subject to a negative moment [A]

truss bar

a longitudinal bar bent up or down at points of moment reversal in a reinforced concrete beam [C]

web reinforcement

reinforcement consisting of bent bars or stirrups, placed in a concrete beam to resist diagonal tension

diagonal tension

the principal tensile stresses acting at an angle to the longitudinal axis of a beam

bent bar

a longitudinal bar bent to an angle of 30d or more with the axis of a concrete beam, perpendicular to and intersecting the cracking that could occur from diagonal tension [D]

stirrups

any of the U-shaped or closed-loop bars placed perpendicular to the longitudinal reinforcement of a concrete beam to resist the vertical component of diagonal tension

bottom bar

any of the longitudinal bars serving as tension reinforcement; subject to a positive moment [B]

vertical reinforcement

longitudinal reinforcement placed in a concrete column to absorb compressive stresses, resist bonding stresses, and reduce the effects of creep and shrinkage in the column

lap splice

a splice made by lapping their ends for a length specified in bar diameters

butt splice

a splice made by putting their ends together and connecting them in a positive fashion

welded splice

a butt splice made by arc-welding the butted ends of two reinforcing bars

compression splice

a butt splice made by connecting the butted ends of two reinforcing bars with a mechanical fastener, such as a sleeve clamp

offset bend

a bend displacing a section of longitudinal bar to a position parallel to the original bar, used esp. in the vertical reinforcement of concrete columns

reinforced concrete column

a concrete column designed to act together with vertical and lateral reinforcement in resisting applied forces

lateral reinforcement

spiral reinforcement or lateral ties placed in a concrete column to laterally restrain the vertical reinforcement and prevent buckling

spiral reinforcement

lateral reinforcement consisting of an evenly spaced continuous spiral held firmly in place by vertical spacers

tied column

a concrete column reinforced with vertical bars and individual lateral ties

spiral column

a concrete column with spiral reinforcement enclosing a circular core reinforced with vertical bars [B]

compound column

a structural steel column encased in concrete at least 2 1/2 in. (64 mm) thick, reinforced with wire mesh [C]

composite column

a structural steel section thorougly encased in concrete reinforced with both vertical and spiral reinforcement [C]

reinforced concrete slab

a rigid planar structure of concrete designed to act together with principal and secondary reinforcement in resisting applied forces

principal reinforcement

reinforcement designed to absorb the stresses from applied loads and moments

shrinkage reinforcement

reinforcement placed perpendicular to the principal reinforcement in a one-way slab to absorb the stresses resulting from shrinkage or changes in temperature; also called "temperature reinforcement"

topping

a thin layer of high-quality concrete placed over a concrete base to form a floor surface

bonding layer

a thin layer of mortar spread on a moistened and prepared existing concrete surface prior to laying a new concrete slab

one-way slab

a concrete slab of uniform thickness reinforced in one direction and cast integrally with parallel supporting beams; are suitable only for relatively short spans [A]

beam-and-girder slab

a one-way slab supported by secondary beams, which in turn are supported by primary beams or girders [B]

ribbed slab

a reinforced concrete slab cast integrally with a series of closely spaced joists, which in turn are supported by a parallel set of beams; also called "joist slab" [C]

two-way slab

a concrete slab of uniform thickness reinforced in two directions and cast integrally with supporting edge beams or bearing walls on four sides; are economical for medium spans with intermediate to heavy loads [D]

continuous slab

a reinforced concrete slab extending as a structural unit over three or more supports in a given direction [E]

distribution rib

a rib formed perpendicular to the joists of a ribbed slab to distribute possible load concentrations over a large area [I]

joist band

a broad, shallow supporting beam for a ribbed slab that is economical to form since its depth is the same as that of the joists [H]

pan

a reusable metal or fiberglass mold used in forming a ribbed slab [G]

tapered endform

a pan tapered to form thickened joist ends for greater shear resistance in a ribbed slab [F]

panel

a portion of a reinforced concrete slab bounded on all sides by the centerlines of columns, beams, or walls

panel strip

a strip running in each direction of a two-way slab, within which moments per foot are assumed to be constant

middle strip

a panel strip, one-half panel in width and symmetrical about the panel centerline

column strip

a panel strip occupying the adjacent quarter panels on both sides of a column centerline

flat plate

a concrete slab of uniform thickness reinforced in two or more directions and supported directly by columns without beams or girders

flat slab

a flat plate thickened at its column supports to increase its shear strength and moment-resisting capacity; are suitable for heavily loaded spans

mushroom construction

flat slab construction utilizing column capitals and drop panels

waffle slab

a two-way concrete slab reinforced by ribs in two directions; are able to carry heavier loads and span longer distances than flat slabs

dome

a square metal fiberglass pan used in forming the ribs of a waffle slab

punching shear

the potentially high-shearing stress developed by the reactive force of a column on a reinforced concrete slab

shear head

the overstressed region of a reinforced concrete slab at a column support

drop panel

the portion of a flat slab thickened around a column or column capital to increase its resistance to shear [C]

column capital

the head of a column support for a flat slab enlarged to increase the plate area in shear [D]

exterior panel

a panel of a flat slab having at least one edge that does not adjoin another panel

interior panel

any panel of a flat slab adjoining other panels along all four edges

precast concrete

a concrete member or product that is cast and cured in a place other than where it is to be installed in a structure

solid flat slab

a precast, prestressed concrete plank suitable for short spans and uniformly distributed floor and roof loads

hollow-core slab

a precast, prestressed concrete plank internally cored to reduce dead weight

topping

a layer of reinforced concrete cast to form a composite structural unit with a precast concrete floor or roof deck

single tee

a precast, prestressed concrete slab having a broad, T-shaped cross section

double tee

a precast, prestressed concrete slab having two stems and a broad cross section resembling the capital letters TT

inverted tee

a precast, prestressed ledger beam having a cross section resembling an inverted capital T [F]

L-beam

a precast, prestressed ledger beam having a cross section resembling the capital letter L [E]

ledger beam

a reinforced concrete beam having projecting ledges for receiving the ends of joists or slabs [D]

prestressed concrete

concrete reinforced by pretensioning or posttensioning high-strength steel tendons within their elastic limit to actively resist a service load

prestress

to introduce internal stresses to a concrete member in order to counteract the stresses that will result from an applied load

pretension

to prestress a concrete member by tensioning the reinforcing tendons before the concrete is cast

tendon

a high-strength steel strand or bar for prestressing concrete

strand

a cable composed of high-strength steel wires twisted about a core

casting bed

a long horizontal slab on which a number pretensioned concrete members may be prestressed, formed, and cast simultaneously

abutment

a structure for anchoring the reinforcing tendons in the pretensioning of a concrete member

anchor

a mechanical device for locking a stressed tendon in position and delivering the prestressing force to the concrete

jacking force

the tensile force exerted temporarily by a jack in the prestressing of a concrete member