Issue 63

M. Khalaf et alii, Frattura ed Integrità Strutturale, 63 (2023) 206-233; DOI: 10.3221/IGF-ESIS.63.17

not recommended to drill any opening at the shear zone because the strength loss reached 57% even with the strengthening, especially for blast resisting structure. In addition, the strength was only recovered from approximately 11.95 to 32.46%. Other researchers studied the matter of opening existence and the strengthening with the fiber reinforced polymer (FRP) in flexure only such as Almusallam et al. [23]. Recently, since the majority of the available well-known and normally used analysis software programs by numerous researchers don’t give the detailed fracture results due to the continuum simulation of materials such as concrete, some researchers such as De Maioet. al. [24] mainly spotlighted on the aspect of the cracking behavior of the RC structures by adopting an effectiveness numerical fracture and an embedded truss models to simulate the crack propagation, crack width, crack spacing and concrete-rebar interaction respectively. Also, Ferrian et al. [25] studied the cohesive approach by investigating the details of cracking and de-bonding phenomena arising in the concrete phase using two equations describing the stress requirement and the energy balance respectively. This approach can be used to simulate the FRP sheets gluing agent to the appropriate concrete surface. Finally, studying the urgently post-planning opening existence in the RC beams shear zone and CFRP strengthening under various service loads levels on the structural behavior as a whole using the well known finite element analysis software ANSYS [26] assuming full interacted CFRP sheets to the appropriate concrete face is the main key in the current research. Hereinafter, the investigation program is presented, numerical modeling validation and evaluation are investigated and consequently the gained results are stated and analyzed to deduce the more important conclusions and recommendations.

I NVESTIGATION PROGRAM

F

irst of all, the current research investigated the openings drilled within the RC beams shear zone and the CFRP strengthening technique influence on the whole structural behavior enhancement of certain models cases. The shear zone wide is the distance between the applied concentrated load and the nearest support.

Figure 2: The research program details.

209