PSI - Issue 42

Rami A. Hawileh et al. / Procedia Structural Integrity 42 (2022) 1198–1205 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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4.2. Effect of flange geometry The effect of flange geometry on the shear capacity of RC T-beams was assessed in this section. Two main parameters that influenced the shear capacity were investigated: flange thickness-to-overall height of the T-beam ( h f / h ) and flange width-to-web width ( b f / b w ) ratios. The shear capacity values (experimental and predicted) were plotted against the h f / h and b f / b w . Fig. 2 shows the plotted points of the experimental and predicted shear values. a b

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Fig. 2. Influence of (a) h f / h ; (b) b f / b w on the shear capacity

The experimental values of the shear capacity show approximately an increasing trend with increasing h f / h and b f / b w ratios. This indicates that increasing the flange dimensions upgrades the shear capacity of the T-beams. It is evident from Fig. 2 that all design provisions failed to capture the increasing trend of shear capacity with h f / h and b f / b w ratios. In fact, most of the predicted points indicate a reduction in shear value as the ratio of h f / h increases. One explanation could be that the design guidelines do not include the flange dimensions in their models; therefore, the predicted capacity was solely based on the height of the member and its effective depth. The only equation that provided a similar trend as the experimental points in Fig. 2 was by Ramadan et al. (2022). This is because the shear design equation includes the effect of the size of the flange and shear reinforcement in the flange. 5. Conclusions The accuracy of four design shear guidelines (ACI318-19, CSA23.3-4, BS8110-1:1997, and Eurocode2) and three models from the literature (Zararis et al. (2006), Ramadan et al. (2022), and Thamrin et al. (2016)) for evaluating the shear capacity of RC T-sections are assessed with the help of an experimental data base. The following conclusions were drawn: • All current design provisions underestimate the shear capacity of RC T-beams, as the models do not account for the flange contribution to shear capacity. • With respect to the design guidelines, Eurocode provided the most conservative predictions, while the CSA23.3-4 provided the most accurate predictions. • As for the developed models in the literature, Zararis et al. (2006) model succeeded to capture the true shear capacity of T-beams with safe and accurate predictions, while Thamrin et al. (2016) provided very conservative predictions. • The design codes significantly underestimated the capacity of the T-beams without stirrups compared to the beams that had stirrups. • Increasing the flange thickness-to-overall height and flange width-to-web width ratios increases the shear capacity of RC T-beams. It recommended for future studies to investigate different flange geometries, with different reinforcement ratios to develop accurate models to predict the shear capacity of RC T-beams that aids in economical design of T-beams.