الفهرس 
CHAPTER (1): INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
In addition to the dramatic aesthetic effect of curved structures, the structural efficiency of arches and other curved members make them an attractive choice for both architects and engineers. Many commercial and industrial structures rely on curved members where straight members would be impractical.
The existence of transverse openings will convert the behavior of simple beam into more complex behaviors, as they make a sudden change in the cross section dimension of the beam. Therefore, as the opening represents a weak link, the failure plane usually goes through the opening. The ultimate strength, shear strength, crack width and stiffness could also be highly influenced. In addition, the provision of openings produces discontinuities or disturbances in the normal flow of stresses, causing a stress concentration and making early cracking around the opening area. Due to the Similarity of any discontinuity, special reinforcement or enclosing strengthening of the opening close to its periphery, should be added in appropriate amount to control the width of crack and prevent the expected premature failure of the beam.
This study investigates the impact of openings on the behavior of arched beams with openings and the effectiveness of different strengthening materials in enhancing their performance.
The study involves three stages. The first stage focuses on the effect of openings on the behavior of curved beams. The second stage examines the effect of different strengthening materials, including carbon fiber wraps (CFRP), glass fiber wraps (GFRP), and steel plates (SP), on the deflection and failure load in the presence of openings. In the third stage.
Finite Element models using ABAQUS are used to simulate the tested beams with different strengthening materials, and the differences between beams with and without openings are analyzed. The results show that the presence of openings negatively affects the ultimate load, deflection, and ductility ratio of arched beams.
Opening existence affects negatively on the behavior of the arched beam, as it drops the deflection by about 86% and the ultimate load by about 74%, while the tensile strain was decreased by about 93%.
Regarding strengthening, beams strengthened with steel plates (SP) demonstrate a higher ultimate load, approximately 5.6% and 21% higher than beams strengthened with carbon fiber (CFRP) and glass fiber (GFRP), respectively.
Moreover, the deflection of beams strengthened with steel plates (SP) is 6.4% and 8.9% higher than beams strengthened with (CFRP) and (GFRP). The presented work is introduced to offer a valuable solution to some developed systems for controlling, repairing, and supporting structures.
For tensile strain, beams strengthened by CFRP are 14%, and 11% higher than beams strengthened with (SP) and (GFRP).
Using finite element simulation was useful for giving a high agreement level with the experimental work, which is considered a good indication for the arched beam behavior.
Key words: Strengthening; arch beams; openings; strengthening techniques.