Stirrup is one of the fundamental part in a reinforced concrete design. In the design, stirrups are to hold the main reinforcement rebar together. For beams, these close loop are called stirrups. While when used in columns, they are called ties.
Stirrups and ties have the same purpose which is to hold the main reinforcement, preventing the reinforced concrete structure to buckle especially during strong winds and earthquake. Stirrups and ties are the perpendicular to the direction of the main reinforcement.
Stirrups and ties have important parts, these are the hooks and the bends. Hooks acts as the length extension to prevent the stirrups to split.
Hooks are designed for the resistance of buckling and during seismic activities. And most especially, hooks are to prevent the slippage of the rebar to keep the stirrups hold the main reinforcement tight. Bends are provided to keep the hooks in place and serves as an anchorage to the main reinforcement.
The most common bend angle of the stirrups are 90 degrees, 135 degrees and 180 degrees. Of which these bend angle provides sufficient resistance to seismic activities like earthquake and any other lateral forces.