Reliability Analysis of Debonding in Steel Beams Strengthened with Externally Bonded CFRP Composites

Abstract

This paper presents the details of a reliability analysis of the debonding in steel beams strengthened with externally-bonded carbon fiber-reinforced polymer (CFRP) composites. A comprehensive experimental database of CFRP-strengthened steel beams and the corresponding double-lap shear joints was compiled. The experimental database was used to quantify the modeling uncertainty for debonding failures based on the analytical formulations that are most commonly adopted in design guidelines. A Monte Carlo simulation (MCS), was used to calculate the resistance factors to achieve a target reliability index of 3.5, for different design scenarios, considering debonding of the FRP as a limit state that would constitute member failure. A sensitivity study was carried out to assess the influence of individual design variables on the reliability index. It was found that the resistance factors vary with adhesives and surface preparation techniques, and the resistance of the representative specimens and modeling uncertainty play the most important roles in achieving a reliable bond.