CRITICAL DIAGONAL CRACK DEBONDING OF ADHESIVELY BONDED PLATES: THE SHEAR PEELING MECHANISM

摘要

The shear capacity of a reinforced concrete beam or slab depends on the following three components: the ability to resist the sliding action across a critical diagonal crack which is often referred to as the concrete component of the shear resistance V_(uc); the ability to resist the vertical forces across the critical diagonal crack, such as the strength of the stirrups, which is referred to as the steel component V_(us); and the ability of V_(uc) and V_(us) to interact that is to achieve their capacities simultaneously. Extensive theoretical and experimental research on steel plated beams has shown that steel plating can only enhance V_(uc) because the shear deformation associated with crack sliding causes debonding of the plate before the stirrups can be stretched to achieve V_(us), that is there is no interaction between V_(uc) and V_(us). This mechanism of debonding is referred to as critical diagonal crack debonding or shear peeling. In this paper, this debonding or peeling mechanism will be described. It will be shown that this debonding mechanism can be applied to steel tension face plated beams, steel side plated beams, steel compression face plated beams, and to angle or channel sections bonded to beams. Tests will also be shown that confirm that the critical diagonal crack debonding mechanism also occurs in FRP plated beams.