Localized Effects in Walls Strengthened with Externally Bonded Composite Materials

The localized effects and, particularly, the stress and deformation concentrations near edges, mortar joints, and irregular points in walls strengthened with externally bonded composite materials are studied. To quantify the structural behavior and to cope with the coupling of large-scale and localized-scale effects, a substructuring procedure that uses a specially tailored high-order finite element is developed. The specially tailored element accounts for the bidirectional behavior of the wall and for the interfacial interaction between the adhesively bonded components. The formulation uses a first-order shear deformation orthotropic plate theory for the independent modeling of the existing wall and the composite layers and a high-order theory for the modeling of the displacement fields of the adhesive layers. A static condensation-based substructuring procedure is used for the formulation of a superelement. The computational strength and the convergence characteristics of the high-order superelement formulation are demonstrated numerically. The superelement formulation is used to study the localized effects in a masonry assemblage strengthened with composite materials. This unique structural form is characterized by a vast dispersion of geometrical and elastic scales, presence of irregular regions, and concentrations of stresses. These localized three-dimensional (3D) stress fields are characterized and their sensitivity to various mechanical and geometrical properties is assessed. Conclusions regarding the impact of the localized effects are provided. DOI: 10.1061/(ASCE)EM.1943-7889.0000422. (C) 2012 American Society of Civil Engineers.