Real strength of high-performance concrete bridge deck slabs

Deterioration of bridge deck slabs due to corrosion of reinforcement has become increasingly evident over the past 40 years and continues to be the cause of costly repair programmes. Detailing to reduce the risk of corrosion is simpler if the percentage of reinforcement is low. It is now recognised that laterally restrained slabs exhibit strengths far in excess of those predicted by most design codes. This increase in strength can be attributed to arching or compressive membrane action (CMA), and by recognising it in design, lower percentages of reinforcement can be specified. CMA has been incorporated into a small number of design standards. However, problems still exist in translating the arching theory into slabs in practice. The problem is in the assessment of the degree of external lateral restraint inherent in slab structures. This paper presents the results of tests on eight one-third-scale bridge deck edge panel models with target compressive strengths of 100 N/mm². The test programme aimed at realistically modelling the restraint conditions intrinsic in the edge panel of a real bridge deck slab. A method for assessing the real restraint in such a slab was incorporated into an existing arching theory by using an effective slab width concept. The procedure showed good correlation with the test results and with other results reported in the literature.