Issue 57

M. T. Nawar et alii, Frattura ed Integrità Strutturale, 57 (2021) 259-280; DOI: 10.3221/IGF-ESIS.57.19 Steel reinforcement ratio ( ) effect on the time-deflection relationship of tested beams under blast loading For all tested R.C beams it can be noted that the maximum dynamic reaction capacity of beams increases when the amount of the steel reinforcement increases. In all cases, however, the higher amount of steel reinforcement reduces the deflection of beams. It is noted that concrete with high strength values, for the same reinforcement ratio, leads to an increase in the last beam deflection value and a decrease in the last dynamic reaction value. For the same concrete mixture, the mid-span deflection of the beam decreases as the steel reinforcement ratio increases. Due to the increase of steel reinforcement ratio, the neutral axis’s depth increases and as a consequence, the moment of inertia I effective will increase, producing a decrease in deflection of R.C beam as shown in Figs. 28. By reducing the amount of longitudinal reinforcement, the ductility of R.C elements will significantly increase in general.

Figures 28: Time-deflection curves for tested beam models using different reinforcement ratios Steel reinforcement ratio ( ) effect on the flexural toughness results for tested beams under blast loading Figs. 29 show the dynamic reaction-deflection relationship of tested R.C beams with different reinforcement ratios. Flexural toughness results are obtained from the area under the dynamic reactions - deflection curves. It can be observed,

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