A tension control bolt, also known as a TC bolt, is a heavy duty bolt used in steel frame construction. The head is usually domed and is not designed to be driven. The end of the shank has a spline on it which is engaged by a special power shear wrench which prevents the bolt from turning while the nut is tightened. When the appropriate tension is reached the spline shears off. Meets A490 standard and is supplied assembled with A563 DH heavy hex nut and F436 structural washer.