Debonding Inhibiting Mechanism of Strain Localization Plating System

Abstract

Recently, a new plating system was proposed based on a strain localization mechanism for addressing the critical debonding problem in externally bonded reinforcing systems for reinforced concrete (RC) structures. The system delays or inhibits debonding by localizing the large strain of the externally bonded reinforcement in certain areas and leaving other places in a smaller strain condition to ensure that global debonding does not occur. This debonding avoidance strategy is in line with the concept of controlling a flood by channeling water away rather than blocking it. Two techniques have been used to achieve strain localization: (1) a nanotechnology called surface mechanical attrition treatment and (2) variation in the cross-sectional area of bonded reinforcement. To better understand this newly developed system, this paper presents a numerical study of RC beams strengthened with such plating systems. This study leads to a better understanding of the mechanism for inhibiting debonding and the development of a general design strategy for the system. In particular, a critical location is identified for strain localization, which forms the basis for the design of such a system in the future.