Title:
Analytical Prediction of Cover Delamination Failure Mode of RC Beams Strengthened with FRP
Author(s):
Fahed Salahat
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/17/2021
Abstract:
RC beams strengthened with FRP fail in different mechanisms depending on the geometric and material characteristics of these beams. Among the various failure mechanisms involved, cover delamination and plate debonding are classified as premature failure modes since the strain in the FRP at failure does not reach FRP rupture strain. ACI 440.2R has provisions that considers the plate debonding strain limit but not the corresponding cover delamination limit. However, cover delamination typically occurs at lower strain levels compared to plate debonding. Thus, it is imperative to develop a pertinent design model for cover delamination strain limit. In this study, a new analytical approach is introduced to predict the cover delamination strain limit. The derivation employs nonlinear interfacial shear stress distribution, the trilinear representation of the moment-curvature relationship, and analysis of an experimental database composed of (78) beams failed in cover delamination. Closed form formulas are extracted to calculate the FRP strain limit at cover delamination failure using strain compatibility and force equilibrium. The formulas are easy to evaluate based on basic parameters of the beam problem. The results show good correspondence with experimental data.