Reinforced Concrete Flashcards
Concrete in which steel reinforcement is embedded in such a manner that the two materials act together in resisting forces.
Reinforced Concrete, Beton Arme, Ferroconcrete
Concrete having no reinforcement or reinforced only for drying shrinkage or thermal stresses.
Plain Concrete
Constructed of cement-sand-mortar over a wire mesh that has been preshaped over a mold.
Ferrocement
Concrete reinforced with dispersed, randomly oriented fibers of glass or plastic.
Fiber-reinforced Concrete
gfrc
Glass-fiber-reinforce concrete
A grid of longitudinal and transverse steel wires or bars welded together at all points of intersection, usually specified by the size of the grid in inches and the wire gauge.
Welded-wire fabric, Welded-wire Mesh
A mesh of cold-drawn steel wires mechanically twisten together to form hexagonally shaped openings.
Woven-wire-fabric
A system of steel bars, strands, or wires for absorbing tensile, shearing and sometimes the compressive stresses in a concrete member or structure.
Reinforcement
A steel bar for reinforcing concrete, usually specified by a number equivalent to its diameter in eights of an inch.
Reinforcing Bar, Rebar
A reinforcing bar hot-rolled with surface deformations to develop greater bond with concrete.
Deformed Bar
Reinforcement designed to absorb tensile stresses.
Tension reinforcement
Reinforcement designed to absorb compressive stresses.
Compression reinforcement
A concrete section designed or analyzed on the assumption that concrete has n oresistance to tensile stresses.
Cracked Section
A lod that causes the tensile stress in a concrete member t oexceed the tensile strength of the concrete.
Cracking Load
A concrete section in which the tension reinforcement theoretically reaches its specified yield strength as the concrete in compression reaches its assumed ultimate strain.
Balanced Section
A concrete section in which the concrete in compression reaches its assumed ultimate strain before the tension reinforcement reaches its specified yield strength. This is a dangerous condition sice failure of the section could occur instantaneously without warning.
Overreinforced Section
The depth of a concrete section measured from the compression face to the centroid of the tension reinforcement.
Effective depth
The center-to-center spacing of parallel reinforcing bars, the resulting clear distance between the bars being regulated by bar diameter, maximum size of coarse aggregate, and thickness of the concrete section.
Bar spacing
The amount of concrete required to protect steel reinforcement from fire and corrosion, measured from the surface of the reinforcement to the outer surface of the concrete section.
Cover
The of a concrete section between the compression face and the centroid of the tension reinforcement
Effective area of concrete
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.
Effective Area of 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.
Percentage reinforcement
A concrete section in which the tension reinforcement reaches its specified yield strength before the concrete in compression reaches its assumed ultimate strain. This is a desirable condition since failure of the section would be preceded by large deformations, giving prior warning of impending collapse.
Underreinforced Section
The adhesion between two substances, such as concrete and reinforcing bars.
Bond
The adhesive force per unit area of contact between a reinforcing bar and the surrounding concrete developed at any section of a flexural member.
Bond Stress
The length of embedded reinforcement provided beyond a critical section for anchorage.
Embedment Length
A bend or curve given to the end of a tension bar to develop an equivalent embedment length, used where there is insufficient room to develop an adequate embedment length.
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.
Standard Hook
Any of various means, such as embedment length of hooked bars, for developing tension or compression in a reinforcing bar on each side of a critical section in order to prevent bond failure or spitting.
Anchorage
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,
Critical Section
A longitudinal bar bent up or down at points moment reversal in a reinforced concrete beam.
Truss Bar
Any of the longitudinal bars serving as tension reinforcement in the section of a concrete beam or slab subject to a negative moment.
Top Bar
Reinforcement consisting of bent bars or stirrups, placed in a concrete beam to resist diagonal tension.
Web Reinforcement
A concrete beam designed to act together with longitudianal and web reinforcement in resisting applied forces.
Reinforced COncrete Beam
Reinforcement essentially parallel to the horizontal surface of a slab or to the long axis of a concrete beam or column.
Longitudinal Reinforcement
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.
Deep Beam
Any of the longitudinal bars serving as tension reinforcement in the section of a concrete beam or slab subject to a positive moment.
Bottom 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.
Bent Bar
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.
Stirrup
The principle tensile stresses acting at an angle to the longitudinal axis of a beam.
Diagonal Tension
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.
T-beam
Longitudinal reinfocement placed in a concrete column to absorb compressive stresses, resist bending stresses, and reduce the effects of creep and shrinkage in the column. The effective cross-sectional area of vertical reinforcement should not be less than 0.01 nor more than .08 times the gross cross-sectional area of the column, with a minimum of four #5 bars for tied columns and a minimum of six #5 bars for spiral columns.
Vertical Reinforcement
A concrete column designed to act together with vertical and lateral reinforcement in resisting applied forces. Constituting the principal supports for a floor or roof should have a minimum diameter of 10inches, or if rectangular in section, a minimum thickness of 8in, and a minimum gross area of 96sqm, in.
Reinforced Concrete Column
Spiral reinforcement or lateral ties placed in a concrete column to laterally restrain the vertical reinforcement and prevent buckling.
Lateral Reinforcement
Lateral reinforcement consisting of an evely spaced continuous spiral held firmly in place by vertical spacers. It should have a diameter of at least 3/8”. with a maximum center-to-center spacing between spirals of 1/6 of the core diamter, and a clear spacing between spirals not to exceed 3 in, nor be less than 1 3/8” or 1 1/2” times the size of the coarse aggregate.
Spiral Reinforcement
A splice for transferring tensile or compressive stresses from one longitudinal bar to another, made by lapping their ends for a length specified in bar diameters.
Lap Splice
A butt splice made by arc-welding the butted ends of two reinforcing bars.
welded splice
A butt splice made by connecting the butted ends of two reinforcing bars with a mechanical fastener, such as a sleeve clamp.
Compression Splice
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.
Offset Bend
A concrete column reinforced with vertical bars and individual lateral ties. Lateral ties should have a diameter of at least 3/8” (9.5mm). spaced apart not over 48 ties diameters, 16 bar diameters, or the least dimension of the column section. Each corner and alternate longitudinal bar should be laterally supported by the bend of a tie having an included angle of not more than 135d, with no bar being more than 6in (152mm) clear from such a supported bar.
Tied Column
A concrete column with spiral reinforcement enclosing a circular core reinforced with vertical bars.
Spiral Column
A structural steel section thoroughly encased in concrete reinforced with both vertical and spiral reinforcement.
Composite Column
Reinforcement designed to absorb the stresses from applied loads and moments.
Principal Reinforcement
Reinforcement placed perpendicular to the principal reinforcement in a one-way slab to absorb the stresses resulting from shrinkage or changes in temperature.
Shrinkage Reinforcement, Temperature Reinforcement
A thin layer of high-quality concrete placed over a concrete base to form a floor surface.
Topping
A concrete slab of uniform thickness reinforced in one direction and cast integrally with parallel supporting beams. This type of slabs are suitable only for relatively short spans.
One-way slab
A one-way slab supported by secondary beams, which in turn are supported by primary beams or girders.
Beam-and-girder slab
A reinforced concrete slab cast intergrally with a series of closely spaced joists, which in turn are supported by a parallel set of beams. This type of slabs are designed as a series of parallel T-beams and are economical for medium spans with light to medium live loads.
Ribbed Slab. Joist Slab
A concrete slab of uniform thickness reinforced in two directions and cast integrally with supporting edge beams or bearing walls on four sides. This type of slabs are economical for medium spans with intermediate to heavy loads.
Two-way slab
A rib formed perpendicular to the joists of a ribbed slab to distribute possible load concentrations over a larger area, one required for spans between 20 and 30 ft, and two for spans over 30ft.
Distribution RIb
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.
Joist band
A reusable metal or fiberglass mold used in forming a ribbed slab, available in standard 20- and 30-inch widths and a variety of depths.
Pan
A pan tapered to form thickened joist ends for greater shear resistance in a ribbed slab.
Tapered Endform
A reinforced concrete slab extending as a structural unit over three or more supports in a given direction. A continuous slab is subject to lower bending moments than a series of discrete. simply supported slabs.
Continuous Slab
A portion of a reinforced concrete slab bounded on all sides by the centerlines of columns, beams or walls.
Panel
A strip running in each direction of a two-way slab, within which moments per foot are assumed to be constant.
Panel Strip
A panel strip, one-half in width and symmetrical about the panel centerline.
Middle Strip
A panel strip occupying the adjacent quarter panels on both sides of a column centerline.
Column Strip
A concrete slab of uniform thickness reinforced in two or more directions and supprted directly by columns without beams or girders. This type of slabs are suitable for short to medium spans with relatively light live loads. Since there are no column capitals or drop panels, shear governs the thickness of this slab.
Flat Plate
The potentially high-shearing stress developed by the reactive force of a column on a reinforced concrete slab.
Punching Shear
The overstressed region of a reinforced concrete slab at a column support.
Shear Head
The portion of a flat slab thickened around a column or column capital to increase its resistance to shear.
Drop Panel
A flat plate thickened at its column supports to increase its shear strength and moment-resisting capacity. This type of slabs are sutiable for heavily loaded spans.
Flat Slab
Flat slab construction utilizing column capitals and drop panels.
Mushroom Construction
The head of a column support for a flat slab enlarged to increase the plate area in shear.
Column Capital
A two-way concrete slab reinforced by ribs in two directions. This type of slabs are able to carry heavier loads and span longer distances than flat slabs,. Supporting beams and drop panels can be formed by omitting dome forms in selected areas.
waffle Slab
A square metal or fiberglass pan used in forming the ribs of a waffle slab, available in standard 19 and 30 inches widths and a variety of depths.
Dome
A panel of a flat slab having at least one edge that does not adjoint another panel.
Exterior panel
Any panel of a flat slab adjoining other panels along four edges.
interior panel
A precast, prestressed concrete plank suitable for short spans and uniformly distributed floor and roof loads.
Solid Flat Slab
A precast, prestressed concrete plank internally cored to reduce dead weight. Hollow-core slabs are suitable for medium to long spans and uniformly distributed floor and roof loads.
Hollow-core slab
A precast, prestressed concrete slab having a broad, T-shaped cross section.
Single Tee
A precast, prestressed concrete slab having two stems and a broad cross section resembling the capital letters TT.
Double Tee
A precast, prestressed ledger beam having a cross section resembling an inverted capital T.
inverted tee
A precast, prestressed ledger beam having a cross section resembling the capital letter L.
L-beam
A reinforced concrete beam having projecting ledges for receiving the ends of joists or slabs.
Ledger Beam
Concrete reinforced by pretensioning or posttensioning high-strength steel tendons within their elastic limit to actively resist a service load. The tensile stresses in the tendons are transferred to the concrete, placing the entire cross section of flexural member in compression. The resulting compressive stresses counteract the tensile bending stresses from the applied load, enabling the prestressed member to deflect less, carry a greater load, or span a greater distance than a conventionally reinforced member of the same size, proportion and weight.
Prestressed Concrete
A high-strength steel strand or bar for prestressing concrete.
Tendon
A cable composed of high-strength steel wires twisted about a core.
Strand
A long horizontal slab on which a number of pretensioned concrete members may be prestressed, formed, and cast simultaneously.
Casting Bed
A structure for anchoring the reinforcing tendons in the pretensioning of a concrete member.
Abutment
A mechanical device for locking a stressed tendon in position and delivering the prestressing force to the concrete, either permanently in a posttensioned member or temporarily during hardening of a pretensioned concrete member.
Anchor, Anchorage
The tensile force exerted temporarily by a jack in the prestressing of a concrete member.
Jacking Force
A hydraulic device for stretching and stressing tendons in the prestressing of a concrete member.
Jack
To introduce internal stresses to a concrete member in order to counteract the stresses that will result from an applied load.
Prestress
To prestress a concrete member by tensioning the reinforcing tendons before the concrete is cast. The tendons are first stretched between two abutments until a predetermined tensile force is developed. COncrete is then cast in formwork around the tendons and fully cure. Finally, the tendons are cut, and the tensile stress in the tendons are transferred to the concrete through bond stresses.
Pretension
The tensile force in the reinforcing tendons transferred to a concrete member at the time of stressing.
Initial prestress
A reduction in initial prestress resulting from the combined effects of creep, shrinkage, or elastic shortenign of the concrete, relaxation of the reinforcing steel, friction losses resulting from the curvature of draped tendons and slippage at the anchorages.
Loss of Prestress
The internal stress that exists in a prestressed concrete member after all losses in prestress have occured.
Final Prestress
The final prestress in a prestressed concrete member, including the effect of the weight of the member but excluding the effect of any superimposed load.
Effective Prestress
The prestressing of a concrete member to a level of stress such that nominal tensile stresses exist at design or service loads.
Partial Prestressing
To prestress a concrete member by tensioning the reinforcing tendons after the concrete has set. Unstressed tendons are placed in sheaths before concrete is cast in formwork around the tubes. After the concrete has cured, the tendons are clamped on one end and jacked against the concrete on the other end until the required force is developed. The tendons are then anchored on the jacking end and the jack removed.
Posttension
Posttensioning in which the reinforcing tendons are bonded to the surrounding concrete by injecting grout into the annular spaces around the strands.
Bonded Posttensioning
Posttensioning in which the annular spaces around the reinforcing tendons are not grouted, allowing the tendons to move relative to the surrounding concrete.
Unbonded Posttensioning
A tube for encasing tendons in a posttensioned member to prevent their bonding to the concrete during placement.
Sheath
To prestress a concrete member by pretensioning some of the tendons and posttensioning others.
Pre-posttension
A tendon having a straight trajectory coincident with the centroidal axis of a prestressed concrete member. When tensioned, the tendon produces a uniformly distributed compressive stress across the section that counteracts the tensile stress from bending.
Concentric Tendon
A tendon having a straight trajectory not coincident with the centrodal axis of a prestressed concrete member. When tensioned, the tendon produces an eccentric prestressing force that reduces the compressive stress across the section to that produced by bending alone.
Eccentric Tendon
A posttensioning tendon having a parabolic trajectory that mirrors the moment diagram of a uniformly distributed gravity load. When tensioned, the tendon produces a variable eccentricity that responds to the variation in applied bending moment along the length of the member.
Draped tendon
The concept of prestressing a concrete member with draped tendons, theoretically resulting in a state of zero deflection under a given loading condition.
Load Balancing
A pretensioning tendon that approximates the curve of a draped tendon with straightline segments, used in the pretensioning process since the prestressing force does not allow for draping the tendon.
Depressed Tendon
