الفهرس 
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Abstract
Rectangular openings are sometimes required in existing concrete beams to pass the electromechanical utility ducts. These openings may be located at the beam’s shear regions. The web openings enable the designer to keep the clear height of the floors and reduce the height of the structure, which is required particularly for high building construction, thus leading to an economic design. This research aims to study various strengthening techniques for beams with web opening by using steel plates and Carbon Fiber Reinforced Polymer (CFRP) laminates. Eight reinforced concrete T-beams were casted with overall depth and length of 400-mm and 4500-mm, respectively. Seven specimens were considered simple beams with a cantilever, while the remaining specimen was a double cantilever. The top flange was 600-mm wide and 80-mm thick, and the web width was equal to 200-mm. Each of the seven specimens was tested twice, the first test done for 3000-mm clear span as simple beams and the second test done for 1400-mm clear span as a cantilever. While the double cantilever was tested for each part separately.
The overall tests of the experimental program were sixteen tests seven tests at the beam and nine tests at the cantilever. Five tests were a control tests with and without web opening, the remaining eleven tests were tested after strengthening using different strengthening schemes. The opening dimensions were 200x800 mm located at the shear zone region of six beam specimens. Eight of the cantilever specimens had a rectangular opening with various widths from 200 to 400 mm, while the height was kept constant at 200 mm. The effect of rectangular opening size and strengthening techniques of each specimen was investigated in this research. An analytical model based on the stress-strain characteristics of concrete, steel, and CFRP was adopted and supported by a three- dimensional finite analysis using ABAQUS. It was found that the type of material used for strengthening and its configuration scheme significantly affect the efficiency of strengthening in terms of beam deflection, steel strain, cracking, ultimate capacity, and failure mode of the beam. Finally, some important conclusions were reported.
It was concluded that, Anchoring the beam web and flange at the opening edges is essential to prevent deponding between the beam web and flange. Finally it was found that using an anchored steel box with stiffeners is the best strengthening technique.