Load-Displacement of Masonry Panels with Unbonded and Intermittently Bonded FRP. I: Analytical Model

An experimental study was carried out to develop and test innovative fiber-reinforced polymer (FRP) rehabilitation techniques that meet the stringent requirements of restoration of historical buildings and are cost-effective alternatives applicable to existing masonry structures. In these techniques, FRP reinforcement was either unbonded or intermittently bonded to the masonry wall. In order to analyze performance, extend the range of the investigated parameters, and define limitations, a simplified analytical model was developed to predict the postcracking lateral load-displacement response under biaxial bending. The response of the retrofitted walls cannot be modeled by conventional approaches. The proposed model is based on balancing internal and external work and rigid body mechanics. It is assumed that all postcracking deformations take place at cracks between wall subpanels. Postcracking displacements are calculated from rotation rather than curvature. The adequacy of the model was verified by comparisons with the experimental results and a good agreement was found. The model could be used as the basis for a design method.