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RISS 인기검색어
- 검색키워드
- 저자 : Jafarali Parol (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
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Analysis of reinforced concrete corbel beams using Strut and Tie models
Jafarali Parol,Jamal Al-Qazweeni,Safaa Abdul Salam 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.1
Reinforced concrete corbel beams (span to depth ratio of a corbel is less than one) are designed with primary reinforcement bars to account for bending moment and with the secondary reinforcement placed parallel to the primary reinforcement (shear stirrups) to resist shear force. It is interesting to note that most of the available analytical procedures employ empirical formulas for the analysis of reinforced concrete corbels. In the present work, a generalized and a simple strut and tie models were employed for the analysis of reinforced corbel beams. The models were benchmarked against experimental results available in the literature. It was shown here that increase of shear stirrups increases the load carrying capacity of reinforced concrete corbel beams. The effect of horizontal load on the load carrying capacity of the corbel beams has also been examined in the present paper. It is observed from the strut and tie models that the resistance of the corbel beam subjected to combined horizontal and vertical load did not change with increase in shear stirrups if the failure of the corbel is limited by concrete crushing. In other words, the load carrying capacity was independent of the horizontal load when failure of the beam occurred due to concrete crushing.
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Experimental and numerical investigation of reinforced concrete beams containing vertical openings
Jafarali Parol,Ammar Ben-Nakhi,Shaikha Al-Sanad,Jamal Al-Qazweeni,Hamad J. Al-Duaij,Hasan Kamal 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.3
Horizontal openings in reinforced concrete (RC) beams are quite often used to accommodate service pipelines. Several research papers are available in the literature describing their effect. RC beams with vertical openings are commonly used to accommodate service lines in residential buildings in Kuwait. However, there are lack of design guidelines and best practices reported in the literature for RC beams with vertical openings, whereas the detailed guidelines are available for beams with horizontal openings. In the present paper, laboratory experiments are conducted on nine RC beams with and without vertical openings. Parametric study has been carried out using nonlinear finite element analysis (FEA) with changes in the diameter of the opening, various positions of the opening along the length and width of the beam, edge distance, etc. 50 finite element simulations were conducted. The FEA results are verified using the results from the laboratory experiments. The study showed that the load carrying capacity of the beam is reduced by 20% for the RC beam with vertical openings placed near the center of the beam compared to a solid beam without an opening. Significant reduction in load carrying capacity is observed for beams with an opening near the support (≈15%). The overall stiffness of the beam, crack pattern and failure modes were not affected due to the presence of the vertical opening. Furthermore, an artificial neural network (ANN) analysis is carried out using the FEA generated data. The results and observations from the ANN and FEA are in good agreement with experimental results.
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Meng, Wei,Bachilo, Sergei M.,Parol, Jafarali,Weisman, R. Bruce,Nagarajaiah, Satish Techno-Press 2022 Structural monitoring and maintenance Vol.9 No.3
This study explores the use of the recently developed "strain-sensing smart skin" (S<sup>4</sup>) method for noncontact strain measurements on cement-based samples. S<sup>4</sup> sensors are single-wall carbon nanotubes dilutely embedded in thin polymer films. Strains transmitted to the nanotubes cause systematic shifts in their near-infrared fluorescence spectra, which are analyzed to deduce local strain values. It is found that with cement-based materials, this method is hampered by spectral interference from structured near-infrared cement luminescence. However, application of an opaque blocking layer between the specimen surface and the nanotube sensing film enables interference-free strain measurements. Tests were performed on cement, mortar, and concrete specimens with such modified S<sup>4</sup> coatings. When specimens were subjected to uniaxial compressive stress, the spectral peak separations varied linearly and predictably with induced strain. These results demonstrate that S<sup>4</sup> is a promising emerging technology for measuring strains down to ca. 30 𝜇𝜀 in concrete structures.
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