“Master’s Thesis Defense of Student Mohammed Abbas Ghulam Hussein in the Department of Civil Engineering, Structural Engineering Specialty, on the topic:
Behavior of One-Way RC Slabs With Openings Reinforced with GFRP Bars and Strengthening By CFRP Sheets
The defense took place on Thursday, November 2nd, 2023, under the supervision of Prof. Dr. Ali Hussein Ali Al-Ahmad.
The examination committee was composed of the following esteemed members:
1. Prof. Dr. Abdul Matlub Issa Saeed – University of Baghdad/Faculty of Engineering (Chairperson)
2. Assoc. Prof. Dr. Mehdi Hameed Mohammed – University of Baghdad/Faculty of Engineering (Member)
3. Assoc. Prof. Dr. Walid Awad Wariyosh – Al-Mustansiriya University/Faculty of Engineering (Member)
4. Prof. Dr. Ali Hussein Ali Al-Ahmad – University of Baghdad/Faculty of Engineering (Supervisor)”
Abstract
The requirement to accommodate essential services like lighting and the improvement of air circulation necessitated the implementation of openings in RC slabs. The total stiffness of such slabs could be decreased as a result of these openings. It is essential to conduct studies on the creation of a strengthening method in order to reduce the detrimental impact that these openings have on the behavior of the slabs. FRP may either be utilized as a reinforcing material or as a strengthening technique that may recover the load capacity of a structure.
This study aims to investigate the flexural behavior of one-way concrete slabs with openings reinforced by glass fiber-reinforced polymers (GFRP) bars and strengthening using carbon fiber-reinforced polymer (CFRP) sheets. The experimental work consists of seven one-way concrete slabs that were tested under a two-line load until they failed. All slabs had the same dimension, 750*2650 mm, with a thickness of 150 mm, and were reinforced with the same reinforcement ratio. The experimental work included one specimen without openings and without strengthening as a solid slab. While, the remaining slabs were classified into two groups based on strengthening or un-strengthening slab specimens and were fabricated with two different openings, rectangular and square 250*500 mm, and 250*250 mm respectively. The first group consisted of two specimens with two different openings and without strengthening. While, the second group consisted of four specimens with two different openings and strengthening by using CFRP sheets with two different methods (fully and opening). The test results show that the failure load of existing slabs with mid-span openings decreased by around 41% and 43%, and the service load deflection increased by about 73% and 106% for one and two openings respectively, compared to the solid slab. The utilization of CFRP sheets enhances the flexural load-carrying capacities by about 52% and 44% and decreases the deflection at a service load by about 56% and 53%, respectively for slabs with a fully strengthening method, compared with the un-strengthened slabs. In addition, after all of the geometrical and material characteristics had been characterized, a finite element analysis (FEA) was carried out on all of the experimental works utilizing the ABAQUS (2020) program for the reasons of validation and parametric investigation. Two parameters have been constructed including the strength of the concrete and the thickness of the CFRP sheets. All the numerical results showed a good agreement with the experimental data in terms of the load-bearing capacity and ultimate deflection.
