Evaluation of span-to-depth ratio provisions for deflection control of one-way RC construction

This paper deals with the span-to-depth ratios (SDR) limitation, which is commonly offered as a simplified substitute for a detailed calculation of the deflection, as part of the service limit design verification. The study examines the European (EC2) and the Israeli (SII) codes simplified SDR-based methods. The derivation of the SII approach, which has never been published, is presented. The study is based on comparison of the cross-section depths required by the two simplified procedures, with two detailed procedures - the commonly used European and the American (ACI) ones. This is done through examination of one-way slabs and beams under two extreme typical loads for a wide range of spans. The main purpose of the paper is to show that although the simplified methods are expected to yield conservative results they do not always do. The conclusions further consider the EC2-simplified procedure required iterations, involving the reinforcement amounts, compared with the SII-simplified method that refers only and directly to the given service loads and therefore requires simpler iterations.