STIRRUPS, TIES & CORNER BARS

The term stirrups is usually applied to lateral reinforcement in flexural members and the term ties to lateral reinforcement in vertical compression members.

In uniaxial compression test of concrete, upon reaching the ultimate load failure of concrete occurs where major cracks line up in the vertical direction and the concrete cube would be split up. The development of vertical cracks involves the expansion of concrete in lateral directions. In case the concrete is confined in lateral directions, it was observed that the formation of vertical cracks would be hindered as indicated in past experiments. As a result, the concrete strength is increased with also a rise in failure strain.

The above theory is often used in the design of bridge columns. Steel stirrups are installed at around the vertical main reinforcement. Other than the function of shear reinforcement, it helps to avoid the lateral deformation of interior concrete core so that the strength of concrete column is increased.
Also , Open stirrups are provided principally to resist shear forces in concrete beams and they are applied in locations in which the effect of torsion is insignificant. U-shaped stirrups are placed in the tension side of concrete beams in which shear cracks would occur. However, when concrete beams are designed to resist a substantial amount of torsion, closed stirrups should be used instead.

Concrete beams vary in depth. The deeper the beam, the more shear capacity. When the depth is not adequate, steel stirrups must be added to increase the shear capacity of the beam. These stirrups are usually one piece of steel that is bent into a rectangular shape. Often small diameter steel is used, such as #3 and #4 rebar. The stirrup typically wraps around the bottom and top bars of the beams.

Corner bars are typically used to reinforced the corners of slabs and to tie together vertical and horizontal pieces of rebar.

• STANDARD BEND TYPES (OPEN SHAPES)
• STANDARD BEND TYPES (CLOSED SHAPES)

STANDARD BEND TYPES (OPEN SHAPES)

STANDARD BEND TYPES (CLOSED SHAPES)