Effect of Flangewidth on Shear Strength of R.C T-Beams

Elgohary, Ahmed; Abdelhafiez, Ahmed; Asran, Ahmed G.

doi:10.21608/auej.2019.43430

Cited by 2 publications

(3 citation statements)

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“…By increasing the width ratio ρ b from 3 to 5, the ultimate load P u increased from 6% to 8% for the first group, which did not have any reinforcement in the flange. This is in line with results published in [10] where increasing the effective flange width ratio from 1 to 6 increased the shear strength by about 10 to 30%. When compared to the rectangular specimen "control", we found that P u increased by 165% to 307% due to the existence of compressed thick flanges, a result that agrees with a previous remark that the contribution of concrete compression for beams with T-section chords may be very important, as opposed to what is considered by most existing codes [9].…”

Section: Ultimate Loadsupporting

confidence: 93%

“…The shear strength of RC T-beams without stirrups was studied in [8][9][10]. Thamrin et al [8] found that the shear strength of T-beams was affected by both the flange size and the main longitudinal reinforcement in the web.…”

Section: Introductionmentioning

confidence: 99%

“…For beams with T-or I-sections, for instance, the contribution of the concrete compression chord may be very important, as opposed to what is considered by most existing codes. Reinforced concrete T beams without stirrups in experimental research [10] were tested in the laboratory for shear strength, and the results indicated enhanced shear strength for beams with a flange.…”

Section: Introductionmentioning

confidence: 99%

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Flange Contribution to the Shear Strength of RC T-Beams with Flange in Compression

et al. 2022

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As is well known, in the current design codes, the shear strength of beams is calculated based on the modified truss theory, which does not consider the effects of the flange area of T-beams. The main objective of this paper was to gain a better understanding and enhance the experimental database of the shear behavior of RC T-beams and illustrate the contribution of the flange to the shear capacity of T-beams. To accomplish this aim, a specially designed experimental program was executed, and its test results were analyzed. The main investigated variables were flange dimensions (thickness and width) and its reinforcement (longitudinal and/or vertical). Nineteen simply supported beam specimens were tested to failure under a load configuration made of two concentrated loads. Eighteen specimens had T-shaped cross-sections, while one specimen had a rectangular cross-section for comparison purposes. The items monitored during testing included the development of diagonal cracks, concrete strains, reinforcement strains, maximum loads, and deflections. Test results showed a notable increase in the shear strength of T-beams compared to rectangular beams with the same web size. For the range of variables investigated, increasing the flange thickness-to-beam depth ratio (ρt) from 0.3 to 0.5 increased the shear capacity by up to 54%. In addition, increasing the flange width-to-web width ratio (ρb) from 3 to 5 increased the shear capacity by up to 19%. It was also shown that the results of three-dimensional finite element (FE) analyses using ANSYS compared reasonably well with the test results for all specimens. Finally, based on the test and FE results, a simplified method that accounts for the contribution of the flange to shear capacity was proposed.

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Section: Ultimate Loadsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Flange Contribution to the Shear Strength of RC T-Beams with Flange in Compression

et al. 2022

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Prediction of RC T-Beams Shear Strength Based on Machine Learning

Yehia,

Fayed,

Zakaria

et al. 2024

Int J Concr Struct Mater

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The contribution of shear resisted by flanges of T-beams is usually ignored in the shear design models even though it was proven by many experimental studies that the shear strength of T-beams is higher than that of equivalent rectangular cross-sections. Ignoring such a contribution result in a very conservative and uneconomical design. Therefore, the aim of this research is to investigate the capability of machine learning (ML) techniques to predict the shear capacity of reinforced concrete T-beams (RCTBs) by incorporating the contribution of the flange. Five machine learning (ML) techniques, which are the Decision Tree (DT), Random Forest (RF), Gradient Boosting Regression Tree (GBRT), Light Gradient Boosting Machine (LightGBM), and Extreme Gradient Boosting (XGBoost), are trained and tested using 360 sets of data collected from experimental studies. Among the various machine learning models evaluated, the XGBoost model demonstrated exceptional reliability and precision, achieving an R-squared value of 99.10%. The SHapley Additive exPlanations (SHAP) approach is utilized to identify the most influential input features affecting the predicted shear capacity of RCTBs. The SHAP results indicate that the shear span-to-depth ratio (a/d) has the most significant effect on the shear capacity of RCTBs, followed by the ratio of shear reinforcement multiplied by the yield strength of shear reinforcement ($${\rho }_{{\text{v}}}{f}_{{\text{yv}}}$$ ρ v f yv ), flange thickness ($${h}_{{\text{f}}}$$ h f ), and flange width ($${b}_{{\text{f}}}$$ b f ). The accuracy of the XGBoost model in predicting the shear capacity of RCTBs is compared with established codes of practice (ACI 318-19, BS 8110-1:1997, EN 1992-1-2, CSA23.3-04) and existing formulas from researchers. This comparison reinforces the superior reliability and accuracy of the machine learning approach compared to traditional methods. Furthermore, a user-friendly interface platform is developed, effectively simplifying the implementation of the proposed machine-learning model. The reliability analysis is performed to determine the value of the resistance reduction factor (ϕ) that will achieve a target reliability index ($${\beta }_{T}$$ β T = 3.5).

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Effect of Flangewidth on Shear Strength of R.C T-Beams

Cited by 2 publications

References 0 publications

Flange Contribution to the Shear Strength of RC T-Beams with Flange in Compression

Flange Contribution to the Shear Strength of RC T-Beams with Flange in Compression

Prediction of RC T-Beams Shear Strength Based on Machine Learning

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