in a slip-critical connection, loads are transferred from one element to another through friction forces developed between the faying surfaces of the connection. these friction forces are generated by the extreme tightness of the structural bolts holding the connection together. these bolts, usually tension control bolts or compressible washer tension indicating type bolts, are tensioned to a minimum required amount to generate large enough friction forces between the faying surfaces such that the shear (or tension) load is transferred by the structural members and not by the bolts(in shear) and the connection plates(in bearing). the "turn of the nut" method is also widely used to achieve that state of friction.