Reinforced concrete has
been widely used in construction projects because it allows builders to create
longer spans without intermediate supports while reducing the risk of
structural failures caused by earthquakes or other natural disasters. Concrete
alone cannot withstand tensile stresses from external factors such as wind load
or seismic events; hence reinforcement with rebar has become an integral part
of modern-day construction.
Concrete is one of the most
widely used construction materials in the world due to its strength,
durability, and versatility. However, as great as concrete’s durability and
utility may be, the one flaw with it is that it’s strong in compression but
relatively weak in tension. This means that it is prone to cracks and yields, leading
to a risk of structures falling apart. To maintain the stability of concrete
structures, the construction industry relies on rebars. Rebars helps concrete
structures withstand tensile, bending, torsion, and shearing loads.
Rebar (short for reinforcing
bar) is a steel bar used as a tension device in reinforced concrete and
reinforced masonry structures to strengthen and aid the concrete under tension.
Rebar significantly increases the tensile strength of the structure. The
tensile strength of the steel rebar complements the compressive strength of
concrete to create structures that have a blend of both types of strength. This
reduces the risk of fractures and allows the structure to better withstand
movements and forces that might otherwise cause a concrete structure to fail.
Rebar is often laid in a
grid pattern. This means that different segments of rebar are placed parallel
and perpendicular to one another so that it can withstand tensile forces from
many directions. The deformations on the exterior of the rebar ensure that the
rebar does not slip out of the concrete structure. Sometimes rebar is bent at
the ends to further anchor it in place within a concrete structure. Rebar is
not typically visible in concrete structures because it is usually buried
within the concrete structure.
The most common type of
rebar is carbon steel, typically consisting of hot-rolled round bars with
deformation patterns embossed into its surface. The carbon steel reinforcing
bars may also be coated in zinc or an epoxy resin designed to resist the
effects of corrosion, especially when used in saltwater environments.
Among the various uses of
rebars, they are used in primary reinforcement to provide resistance to support
design loads. In secondary reinforcement they are used for durability and
aesthetic purposes by providing localised resistance to limit cracking and
temperature-induced stresses. In other cases, rebars provide resistance to
concentrated loads, spreading it through a wider area. They assist other steel
bars in accommodating their loads by holding them in the correct position. They
are also used as external steel tie bars to constrain and reinforce masonry
structures, sometimes as a means of building conservation.
Characteristics
of Rebar
Rebar,
primarily composed of steel, exhibits key characteristics that contribute to
its widespread use in construction:
Strength
and Durability: At its core, rebar serves as a reinforcement
material, enhancing the tensile strength of concrete and fortifying structures
against various forces that might compromise their integrity.
Corrosion
Resistance: Recognizing the potential vulnerability of
steel to corrosion, rebar often incorporates corrosion-resistant materials or
is coated with protective layers, ensuring longevity even in challenging
environmental conditions.
Flexibility
in Design: Available in various sizes and shapes, rebar provides
architects and engineers with a flexible tool to meet diverse structural
requirements, enabling innovative and efficient designs.
Thermal
Resistance: Steel and concrete have similar coefficients
of thermal expansion so a concrete structural member reinforced with steel will
experience minimal differential stress as the temperature changes.
Adherence
to Building Codes: Manufactured to meet rigorous industry
standards and building codes, rebar ensures compliance with safety regulations,
assuring the structural integrity of construction projects.