Improving the Deflection Prediction Model from ACI 318

This paper proposes a simple and mechanically sound modification of the deflection prediction model specified by the ACI 318 Building Code. The main idea of the proposal is that shrinkage effect should be taken into account in the assessment of the cracking resistance of bending members. This in turn will have influence on both short and long-term deflection predictions. The proposed modification has been statistically validated using a database of more than 3500 measurements of short- and long-term deflections of 402 reinforced concrete members collected from 36 test programs.