Serviceability Reliability and Expected Costs of RC Beams Designed to Serviceability Specifications of AS3600

AS3600 suggests three serviceability design specifications, ie. refined method, multiplier method and “deemed to comply method”. This paper will carry out a comparative study of these three methods by comparing their serviceability reliability and expected cost of unserviceability. The serviceability limit state considered herein is occupant discomfort due to excessive deflection and loss in utility due to curvature of the floor. The economic consequences due to these serviceability damages can be substantial. Data of serviceability damage due to excessive deflections of structural elements have been collected from various sources and probabilistic models of damaging deflections and unserviceability cost function models developed. These models are later combined with a probabilistic time-dependent deflection model in Monte-Carlo simulation analyses to calculate probabilities of serviceability failure and expected costs of unserviceability for simply supported RC beams. These probabilistic frameworks have been used here in a comparative study of the three serviceability design specifications of AS3600.