Numerical modeling of unreinforced masonry walls strengthened with fiber reinforced polymers

Masonry structures, which have structural components made of brick, stone, and concrete materials and load bearing systems consisting of unreinforced/reinforced masonry walls and columns are commonly encountered worldwide. They are mostly located in Turkey, Mediterranean area, and Middle East territories and have been built since ancient times and has usually historic significance. Avast amount of research from different disciplines have been conducted on masonry structures, which consist of heavy and brick/stone walls to improve their unfavorable behavior when they are subjected to lateral forces such as earthquake loads. Since seismicity is important in Turkey, masonry structural components should be strengthened using fiber reinforced polymers (FRP) in order to get adequate performance on lateral loading. There have been numerous experimental and numerical researches onstrengthening of masonry structural components using FRP in scientific literature during last ten years. The major aim of this thesis is to perform nonlinear analysis of strengthened unreinforced masonry walls (URM) with FRP under vertical and incremental lateral loading. In this context, the cohesion and internal friction angle of Drucker-Prager (DP) yield criterion for masonry constituent are expressed in terms of uniaxial compression strength and the hydrostatic pressure. Using proposed relations, the slight change of the linear part of the compressive and tensile meridians of DP criterion is modified into a curve. The considerable deficiency of this approach is the ending point of nonlinear finite element analysis and definition of rupture in implementation of masonry walls and columns; hence the definition of rupture criterion is newly introduced in this study. For the URM walls, the end point for the analysis is determined by defining a discontinuity of surface between two clay units along the thickness of the mortar which indicates a macro-crack on the wall. This criterion is successfully used in prediction of 17 (seventeen) URM walls with/ without openings and also strengthened walls with FRP which are available in literature experimentally. These numerical modeling studies consist of one unreinforced wall with opening, five unreinforced walls and rest of strengthened walls wrapped with FRP. This thesis which have been improved and applied with the same numerical prediction on the 3 different wall types is currently the unique exemplification in the literature. Similar results obtained numerically with the definition of maximum tensile assumption URM and damaged walls retrofitted with FRP which are experimentally investigated and existed in the literature. Strengthening of undamaged walls are also investigated with the prediction of rupture of FRP and the numerical results obtained are the same of that experimental works.