Abstract:

The effective moment of inertia expressions proposed by Branson and Bischoff are examined by comparing the deflection estimates from these two approaches to the measured deflection values of reinforced concrete beams with high reinforcement ratios (0.024<ρ<0.034). It was found out that both methods yield to deflection estimates in close agreement with the actual values and the method proposed by Bischoff bending deformations of heavily-reinforced concrete beams. Furthermore, the restrained shrinkage cracking was found to cause the deflection response of a concrete beam to be much weaker than the responses estimated by the effective moment of inertia expressions. Finally, the cracking moment estimates from the methods given in ACI 318-05, Eurocode 2 and TS 500 are compared to the experimental cracking moments of reinforced concrete beams. The cracking moment estimates based on the modulus of rupture expression in Eurocode 2 were found to be in closest agreement with the experimental values.

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