In concrete construction, a stirrup is used in concrete beams or columns to hold the main longitudinal rebar in place. They typically are square or rectangular in shape and consist of five 90 degree bends. The bends on the ends of the bar overlap. A variation is the seismic stirrup which has 135 degree bends on the ends instead of 90 degrees. Because stirrups are usually made from smaller diameter bars, it is easy enough to bend one or two of these by hand using just a rul