Rebar, known when massed as reinforcing steel or steel reinforcement, is a steel bar used as a tension device in reinforced concrete and reinforced masonry structures to strengthen and aid the concrete under tension. Concrete is strong under compression, but has low tensile strength. Rebar significantly increases the tensile strength of the structure. Rebar's surface features a continuous series of ribs, lugs or indentations to promote a better bond with the concrete and reduce the risk of slippage.
Two bundles of full-length rebar, which will be placed, bent, or cut as required by installation
An early version of rebar inside the Leaning Tower of Nevyansk
The Alvord Lake Bridge in San Francisco's Golden Gate Park, the first reinforced concrete bridge built in the United States
Rebar has been placed atop a temporary wooden formwork deck prior to pouring concrete. The large horizontal rebar "cages" will be encased within a beam, while several thick vertical rebar stubs will stick out of the pour to form the base of a future column.
Reinforced concrete, also called ferroconcrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ductility. The reinforcement is usually, though not necessarily, steel bars (rebar) and is usually embedded passively in the concrete before the concrete sets. However, post-tensioning is also employed as a technique to reinforce the concrete. In terms of volume used annually, it is one of the most common engineering materials. In corrosion engineering terms, when designed correctly, the alkalinity of the concrete protects the steel rebar from corrosion.
A heavy, reinforced concrete column, seen before and after the concrete has been cast in place around its rebar frame
The novel shape of the Philips Pavilion built in Brussels for Expo 58 was achieved using reinforced concrete
Rebars of Sagrada Família's roof in construction (2009)
Christ the Redeemer statue in Rio de Janeiro, Brazil. It is made of reinforced concrete clad in a mosaic of thousands of triangular soapstone tiles.