Reliability of Super-T PSC girders at serviceability limit state stresses across all span ranges

Reliability assessment gives useful information on the level of performance or adequacy of design rules. There are five standardized Super-T prestressed concrete (PSC) girder sections widely used for bridges in Australia. The Australian standard (AS 5100) requires serviceability limit state criteria of allowable stresses to be met. However, there is not yet an assessment of the performance achieved by these rules. In this study, all potential strand arrangements (more than 50,000) for all Super-T sections, across all feasible span ranges, are assessed. Ten girder-slab bridge decks are analysed; the critical girder in the deck is designed for all possible strand arrangements. Design adequacy is assessed using the annual reliability index. A system reliability analysis is conducted using Ditlevsen bounds to check that none of the four stress limits are exceeded. Generally, it is found that the Super-T girder designs are adequate for most strand arrangements compliant with AS 5100. Further, the reliability varies significantly depending on the selected span, section and strand arrangement. This work informs designers on the reliability performance of Super-T girders designed to AS 5100 and provides background for future revisions of AS 5100.