INITIAL VS. RESIDUAL PRELOAD called-or equated to-the

When the joint is put into service, a variety of things can act to modify the preload in individual fasteners still further. This could be called in-service tension in the bolts.

Each of these preloads or tensions is directly proportional to the amount of potential energy stored in the bolt as it is first tightened, after relaxation occurs, or in service. In most cases these preloads or tensions will also be directly proportional to the clamping force between joint members, but there are exceptions.