الفهرس 
Steel-Concrete Composite StructuresOnly 14 pages are availabe for public view
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Abstract
The concrete-encased steel beams have become one of the essential composite members utilized in recent years in the construction of the bridges and buildings and creating openings in the structural members is newly appearing to pass the large ducts, air conditioning pipes, and drainage pipes. Also, it illustrated that web openings can have effects on the load-carrying capacities of floor beams based on several factors like the opening dimensions, the opening
shapes, the opening location, and the numbers of the openings. In the current work, eleven simply supported beams were fabricated and tested to investigate the structural performance of fully concrete-encased steel beams with and without web
openings. A rectangular web opening located in the shear zone is created, and its effect on the ultimate bearing capacity was presented and discussed. Glass and carbon fiber wraps (GFRP
wrap, CFRP wrap) and steel plates were applied as strengthening materials using the externally bonded reinforcement technique at the flexure zone or at the shear zone to enhance the structural performance of beams. Finite element (FE) models were investigated using ANSYS 19.0 program and their outcomes were validated by the obtained experimental (EXP.) findings. Test results showed that the ultimate load and its corresponding deflection decreased by about 58.28% and 80.17%, respectively due to the effect of the web opening. Furthermore, shear strengthening of beams with web openings located in the shear zone is more effective than flexural strengthening. Also, using a steel plate is more effective than using carbon fiber
wraps or glass fiber wraps. Based on the FE analysis, high compatibility between both FE and experimental results is achieved. Finally, the effect of several parameters on the ultimate loadcarrying capacity like the web opening location, the number of web openings, the web opening shape, the number of fiber-reinforced polymers (FRP) layers, the steel plate thickness, and the flexural and the shear strengthening at the same time are identified using FE analysis. Thus, for strengthening concrete-encased steel beams without web openings at flexure zone using different layers of CFRP wrap or GFRP wrap and steel plate with different thicknesses. FE results show that the optimum number of CFRP wrap layers is three layers while GFRP wrap is four layers. Finally, using a steel plate with a thickness of 1.5 mm is the preferable choice.