Comparison and optimization of different methods of evaluation of displacements in cracked reinforced concrete beams

The evaluation of deflections of reinforced concrete beams is strongly affected by the cracking of concrete; in order to develop a correct calculation of deflections, it is necessary to define an adequate tension stiffening model and exact prediction of the values of cracking moment and of Young's modulus of elasticity. In this paper, the different models of tension stiffening and the semi-empirical correlations for evaluating the modulus of rupture and the Young's modulus are synthetically described and compared with each other. The analytical deflections computed by means of different models are compared with the experimental results obtained by different authors, and an optimization analysis is developed in order to improve the CEB and ACI models.