Ligatures, also called stirrups, are mainly used to be tied to top and bottom of trench meshes or reinforcing rods, which can form a cage or column to enhance the compressive strength of concrete footings and beams. Ligatures are often used in concrete footings and beams. Ligatures are tied with reinforcing bars to form a rigid cage or column, which make the whole foundation solid and reduce cracking of concrete beams surface.