Anchor bolts are used to attach objects or structures to concrete. These metal bolts are L-shaped with male (external) threads, designed to be installed before concrete is poured. Once the concrete cures, a threaded stud remains to anchor another object to the concrete. These bolts are extensively used on all types of projects, from standard buildings to dams and nuclear power plants. All bolts consist of a threaded end, to which a nut and washer can be attached for the external load.