In the current paper, a finite
element analysis based on the smeared crack model and
interfacial fracture
mechanics
has been carried out to focus upon the effect of structural span on
the intermediate crack-induced debonding. Considering that for structures with
multi distributed cracks, local debonding at some points does not mean a
complete debonding failure, the
mechanism of debonding has been explained from
the macroscopic point of view. Based on this consideration, it has been shown
that at the same levels of midspan bending moments of FRP strengthened girders
with same cross section, as the span length increases, the gradient of FRP
stress distribution decreases. This implies that
interfacial shear stress along
the FRP-concrete interface decreases and consequently the possibility of
debonding decreases.