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Abstrakt:
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The conic yield criteria for reinforced concrete slabs in bending are often used when evaluating
the load‐carrying capacity of slab bridges. In the last decades, the yield criteria combined with
numerical limit analysis have shown to be efficient methods to determine the load carrying
capacity of slabs. However, the yield criteria overestimate the torsion capacity of slabs with high
reinforcement ratios and it cannot handle slabs with construction joints. In this paper, numerical
limit analysis with the conic yield criteria are compared with yield criteria based on an optimized
layer model. The analysis show an increasing overestimation of the load carrying capacity for
increasing reinforcement degrees. Furthermore, yield criteria, which combine the conic yield
criteria with an extra linear criterion due to friction, are presented for slab bridges with
construction joints. The yield criteria for slabs with construction joints are used, in combination
with limit analysis, to evaluate a bridge constructed of pre‐cast overturned T‐beams and in‐situ
concrete. The analysis show that the load carrying capacity is overestimated, when the
construction joints are not considered in the yield criteria.
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