The use of fiber reinforced polymers (FRP) for the seismic retrofit of masonry walls is on the rise. Design formulae are available to estimate the lateral load capacity of the strengthened walls. However, recent experimental data from tests conducted on full scale concrete masonry walls under cyclic lateral loads have shown that these design capacities have not been reached because of the occurrence of other failure modes not accounted for in the design formulae. The limiting failure mode in all test samples referred to in this work was due to premature compression failure of the masonry units at the wall toe. The main goal of the current study is to develop a simple numerical model that can be readily used by practicing engineers to predict accurate levels of design capacities for strengthened masonry walls subjected to lateral loading. The numerical model needs only be sophisticated enough to provide the necessary basic information required for design purposes. A simple and efficient finite element model of the masonry wall was devised using the software package ABACUS/STANDARD. In particular, the model uses a layered shell element which allows the modeling of the masonry in addition to the FRP laminates or strips. The analysis is performed under constant vertical gravity load with monotonically increased lateral load until wall failure. Appropriate mesh sizes, boundary conditions, restraints, modeling of steel reinforcement, and the no-compression criterion for the laminates are evaluated and their effects are illustrated. Finally, a comparison between the numerical lateral loads at failure of the walls with those observed experimentally, for the different strengthening models that were tested in the laboratory, is made. Having confirmed the validity of the theoretical model, other FRP retrofit techniques are also investigated. The simple finite element model provided lateral capacities, for the investigated type and configuration of the masonry walls, which are most consistent with the experimentally observed values, yet significantly lower than predicted by the design formulae currently in use by practicing engineers.
Construction Engineering Department
MS in Construction Engineering
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Online Submission Date
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(2007).Numerical modeling of concrete masonry walls strengthened by fiber reinforced polymers under lateral loads [Master’s thesis, the American University in Cairo]. AUC Knowledge Fountain.
Salama, Mohamed. Numerical modeling of concrete masonry walls strengthened by fiber reinforced polymers under lateral loads. 2007. American University in Cairo, Master's thesis. AUC Knowledge Fountain.