Reinforced Concrete Construction

Reinforced Concrete

Concrete in which steel reinforcement is embedded in such a manner that the two materials act together in resisting forces. Also called Belon anne or Ferroconcrete.

Plain Concrete

Concrete having no reinforcement or reinforced only for drying shrinkage or thermal stresses.

Ferrocement

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

Cast-in-Place Concrete

Concrete deposited in the place where it is required to harden as part of the structure rather than being precast.

Reinforcement

A system of steel bars, strands, or wires used to absorb tensile, shearing, and sometimes compressive stresses in a concrete member or structure.

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.

Balanced Section

A concrete section in which the tension reinforcement theoretically reaches its yield strength as the concrete in compression reaches its ultimate strain, causing both materials to fail simultaneously.

Overreinforced Section

A concrete section in which the concrete in compression reaches its ultimate strain before the tension reinforcement reaches yield strength, resulting in sudden failure.

Underreinforced Section

A concrete section in which the tension reinforcement reaches yield strength before the concrete in compression reaches its ultimate strain, providing warning through large deformations before failure.

Beam

A rigid structural member designed to carry and transfer transverse loads across space to supporting elements.

Simple Beam

A beam having a single span supported at its ends without restraint at the supports.

Semi-continuous Beam

A beam having two spans with or without restraint at the extreme ends.

Cantilever Beam

A beam supported at one end while the opposite end projects beyond the support.

Continuous Beam

A beam resting on more than two supports.

T-Beam

A beam and slab poured simultaneously to form a monolithic structure in which the slab acts as the beam flange.

Reinforced Concrete Beam

A concrete beam designed to work together with longitudinal and web reinforcement in resisting applied loads.

Effective Depth of Section

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

Bar Spacing

The center-to-center spacing between parallel reinforcing bars.

Span of Supports

The distance between posts, columns, or supporting walls.

Concrete Cover

The thickness of concrete protecting reinforcing steel from fire and corrosion, measured from the reinforcement surface to the concrete surface.

Bond

The adhesion between concrete and reinforcing steel.

Bond Stress

The adhesive force per unit area between reinforcing steel and surrounding concrete.

Development Length

The length of embedded reinforcement required to develop its design strength at a critical section.

Embedment Length

The length of reinforcement embedded beyond a critical section.

End Anchorage

The length of reinforcement, hook, or mechanical anchor beyond the point of zero stress.

Hook

A bend provided at the end of a reinforcing bar to develop equivalent embedment length where straight embedment is insufficient.

Longitudinal Reinforcement

Reinforcement placed parallel to the horizontal surface of a slab or the long axis of a beam or column.

Percentage Reinforcement

The ratio of the effective area of reinforcement to the effective area of concrete expressed as a percentage.

Top Bar

A longitudinal reinforcing bar acting as tension reinforcement in a beam or slab subjected to negative moment.

Bottom Bar

A longitudinal reinforcing bar acting as tension reinforcement in a beam or slab subjected to positive moment.

Web Reinforcement

Reinforcement consisting of bent bars or stirrups placed to resist diagonal tension.

Bent Bar

A longitudinal reinforcing bar bent at an angle of 30° or more to resist diagonal tension.

Bent Reinforcing Bars

Bars bent upward near the point of inflection and extended across the support into the adjacent span.

No Bent Bars

Straight reinforcing bars supplemented with additional top bars over supports and bottom bars at midspan.

Truss Bar

A longitudinal reinforcing bar bent upward or downward at points of moment reversal.

Stirrup

U-shaped or closed-loop reinforcement placed perpendicular to longitudinal reinforcement to resist the vertical component of diagonal tension.

Cement

A mixture of sand, water, and gravel

Admixture

A material added to concrete to modify its properties and performance.

Aggregate

Granular material used in concrete that must conform to ASTM specifications.

Water

Used in mixing concrete that is clean and free from injurious of substances

Metal Reinforcement

Steel reinforcement used in reinforced concrete construction.

Standard Hook

A 90°, 135°, or 180° bend made at the end of a reinforcing bar according to industry standards.

180° Standard Hook

A 180° bend plus a 4db extension with a free end not less than 65 mm.

90° Standard Hook

A 90° bend plus a 12db extension at the free end.

Stirrup Hook (≤16 mm)

A 90° bend plus a 6db extension.

Stirrup Hook (20–25 mm)

A 90° bend plus a 12db extension.

135° Stirrup Hook

A 135° bend plus a 6db extension.

Minimum Bend Diameter

The minimum allowable inside diameter of a reinforcing bar bend based on bar size.

Cold Bending

The practice of bending reinforcing bars without heating unless otherwise permitted.

Surface Conditions of Reinforcement

Reinforcing steel must be free of mud, oil, and harmful coatings before concrete placement.

Placing Reinforcement

The proper positioning and support of reinforcement before concrete placement.

Spacing Limits for Reinforcement

Minimum and maximum allowable spacing requirements between reinforcing bars.

Bundled Bars

Groups of up to four reinforcing bars tied together to act as one reinforcing unit.

Reinforced Concrete Column

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

Short Column

A column having an unsupported height not greater than 10 times the shortest lateral dimension of its cross section.

Long Column

A column having an unsupported height greater than 10 times the shortest lateral dimension of its cross section.

Tied Column

A concrete column reinforced with vertical bars and individual lateral ties.

Vertical Reinforcement

Longitudinal reinforcement placed in a concrete column to absorb compressive stresses, resist bending stresses, and reduce creep and shrinkage.

Lateral Reinforcement

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

Spiral Reinforcement

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

Bundled Reinforcement

Two to four reinforcing bars tied together in direct contact to act as one reinforcing unit.

Lateral Ties

Reinforcement enclosing longitudinal bars in compression members to provide lateral support and prevent buckling.

Spiral Column

A concrete column with spiral reinforcement enclosing a circular core reinforced with vertical bars.

Composite Column

A column in which structural steel is embedded within the concrete core of a spiral column.

Combined Column

A column with structural steel encased in reinforced concrete at least 70 mm thick with surrounding wire mesh.

Lally Column

A fabricated steel post, sometimes filled with concrete, used to support girders, beams, or other structural members.

Offset Bars

Column reinforcing bars bent to accommodate changes in column location while maintaining structural continuity.

Floor System

The horizontal structural system that supports live and dead loads and transfers them to beams, columns, or load-bearing walls.

Live Load

Movable loads imposed on a structure such as people, furniture, and equipment.

Dead Load

Permanent static loads consisting of the weight of the structure and its materials.

Environmental Load

Loads caused by wind, earthquakes, rainwater, temperature changes, and other environmental effects.

Reinforced Concrete Slab

A rigid concrete slab designed to act together with principal and secondary reinforcement in resisting applied forces.

Principal Reinforcement

Reinforcement designed to resist stresses caused by applied loads and bending moments.

Shrinkage Reinforcement

Reinforcement placed perpendicular to principal reinforcement to resist stresses caused by shrinkage and temperature changes.

Temperature Reinforcement

Another term for shrinkage reinforcement.

Concrete Topping

A thin layer of high-quality concrete placed over an existing concrete surface to form a finished floor.

Bonding Layer

A thin layer of mortar applied to an existing concrete surface before placing a new concrete slab.

Expansion Joint

A gap between adjacent concrete members that permits movement due to temperature changes without causing damage.

Construction Joint

A joint where two successive concrete placements meet.

Isolation Joint

A joint allowing movement between a concrete slab and adjoining structural elements such as walls and columns.

Control Joint

A joint intentionally formed to control where concrete cracks due to tensile stresses.

One-Way Slab

A slab reinforced primarily in one direction and supported by two parallel beams.

Two-Way Slab

A slab reinforced in two directions and supported on all four sides.

Beam-and-Girder Slab

A one-way slab supported by secondary beams, which are in turn supported by primary beams or girders.

Continuous Slab

A reinforced concrete slab extending continuously over three or more supports.

Flat Plate

A slab of uniform thickness supported directly by columns without beams or girders.

Flat Slab

A flat plate thickened at column supports with drop panels or column capitals to increase shear strength.

Waffle Slab

A two-way ribbed concrete slab capable of carrying heavier loads over longer spans.

Precast Concrete Slabs

Concrete slab members cast and cured before installation in the structure.

Solid Flat Slab

A precast prestressed concrete plank suitable for short spans.

Hollow-core Slab

A precast prestressed concrete plank with internal voids to reduce dead weight.

Single Tee

A precast prestressed concrete slab having a single T-shaped section.

Double Tee

A precast prestressed concrete slab with two stems resembling the letters TT.

Inverted Tee

A precast prestressed ledger beam with an inverted T-shaped cross section.

L-Beam

A precast prestressed ledger beam with an L-shaped cross section.

Ledger Beam

A reinforced concrete beam with projecting ledges supporting the ends of joists or slabs.

Schedule of Wall Reinforcement

A standard table specifying reinforcement sizes, spacing, and placement for walls of various thicknesses.

Foundation

The lowest division of a building or structure, constructed partly or wholly below ground, designed to support the superstructure and transmit its loads safely to the earth.