The Affection of “kb” Coefficient in the Calculation of the Crack Width

The calculation of the maximal crack width, include the effect of adhesion between FRP bars and the concrete. The value of “kb” coefficient is given by recommendations, but is still unclear his true value. The adhesion between concrete and the bars depends in concrete compressive strength, bar diameters and the type of bar surface. In absence of sufficient experimental data, the codes and the recommendations give to us “kb” values that are part of analytical calculations for crack width value. In this article, in base of experimental testing, are given values of “kb” coefficient for the beams reinforced with GFRP and CFRP bars.

Keywords:

crack width, GFRP bars, CFRP bars concrete beam, serviceability state design,

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