الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Masonry is the oldest building material that is still widely used in the construction industry. Also unreinforced masonry is the construction system in most of the historic structures and a considerable percentage of existing residential buildings in Egypt. One of the important disadvantages of unreinforced masonry construction is its low resistance to tensile stresses and lateral loads. Material deterioration can cause cracking and may lead to total failure of such structures, so there is a need for appropriate strengthening of deteriorated structures and a major need for appropriate numerical model.
The primary aim of this research is to develop and evaluate a numerical approach for modeling of masonry structures that takes into account the nonlinear behavior and complex geometry and can predict locations of cracks. The model can also expect whenever there is a chance for total failure or not and design the strengthening type locations as well as volume of strengthening material.
In order to achieve the study goals; extensive experimental investigation of the material mechanical properties are evaluated. One of the most important mechanical properties is stress-strain curve relation, which has been developed, in order to provide the suitable numerical parameter for the numerical model. The numerical model will use the stress-strain relation to simulate accurately the structural behavior for the masonry structures in terms of ultimate loads and deformations.
A numerical investigation for experimentally tested reinforced masonry beams is evaluated to ensure the validity of the numerical model with the provided mechanical parameters to simulate the composite action between the masonry and the used reinforcement.
The study also presents experimental and numerical investigation of strengthening masonry wallets and vaults using FRP composites, as well as other traditional methods such as steel reinforcement bars, Ferro-cement layers and a new tested method using polymer mortar layers. The conducted experimental program is explained and the maximum capacity and failure mode associated with each strengthening technique are presented.
The experimental results for wallets using confining FRP layer found to be very efficient method, where the failure load is double that of the control walls. The experimental results for vaults shows that all strengthening techniques using steel reinforcement bars, Ferro-cement layers and FRP are efficient methods, however the use of FRP are much easier and have excellent stress to weight ratio also the use of glass fiber composites makes it as cheap as other techniques. Using polymer mortar was the least effective technique. The enhancement of the failure loads to the control samples failure loads were recorded to be 185% for vaults strengthened with FRP sheets, and about 160% for vaults strengthened with traditional strengthening techniques which are the steel reinforcement and Ferro-cement wire mesh.
All the experimental results are compared to the numerical results, in order to validate the numerical finite element model created using commercially available finite element program ANSYS V.12, and the compared results between experimental and numerical proved that the model could expect accurately the ultimate failure loads, the load displacement curves and the modes of failure for strengthened masonry assemblage.
Finally in order to apply the studied numerical model into the real cases, a case study is conducted for the Sodoun dome “ a deteriorated heritage dome”, this study provide another validation for the numerical model and to demonstrate its ability to simulate correctly the masonry heritage structures, and the strengthening that may be required to sustain its stability. The presented results demonstrates that the numerical model can simulate the masonry structures with acceptable accuracy for its structural behavior, also can be used to explain the deterioration occurred for such structures, also model can study the efficiency and the type of the proposed strengthening techniques used to repair these deteriorated structures, and can explain the reasons of the cracking and expect the failure loads of these structures to help us achieving more safety to such heritage structures.