Proposal for the extension of the Eurocode shear formula for one-way slabs under concentrated loads

• Transverse load redistribution gives a larger shear capacity for slabs than beams.
• The comparison between experiments and the shear formula defines the limit state.
• Monte Carlo simulations give the enhancement factor for the increased capacity.
• A new formula for the shear capacity of slabs under concentrated loads close to supports is proposed.

A large number of existing reinforced concrete solid slab bridges in the Netherlands are found to be insufficient for shear when assessed for the governing live load models. However, due to transverse load redistribution, the shear capacity of reinforced concrete slabs under concentrated loads is larger than the capacity of beams, on which the code provisions for shear are based. Therefore, an extension of the Eurocode shear provisions for the case of slabs under concentrated loads in shear may be warranted. To study the increase in capacity of slabs as compared to beams, a series of experiments on concrete slabs was carried out. These experimental results are combined with Monte Carlo simulations to quantify the increase in shear capacity in slabs as a result of transverse load redistribution. From the analysis of different subsets of experiments follows a proposal to extend the Eurocode shear provisions for the case of slabs under concentrated loads. Using this new expression and allowing larger shear stresses in slabs under concentrated loads results in less shear-critical cross-sections for existing slab bridges.