Assessment of the Shear Capacity of Existing Reinforced Concrete Solid Slab Bridges

Abstract

Several existing reinforced concrete solid slab bridges in the Netherlands do not meet the criteria for shear when calculated according to the recently implemented Eurocodes. The shear capacity is assessed by comparing the design beam shear resistance to the design value of the applied shear force due to the dead load, permanent load and live load. Transverse load redistribution which occurs in slabs is not taken into account. To evaluate a large number of slab bridges, a first round of assessments is necessary to determine which bridges need a more detailed shear analysis. A series of 26 slabs and 12 slab strips are tested until shear failure. The results of these experiments are compared to the state-of-the-art in beam shear research to compare the shear behavior of beams nd slabs. Recommendations for the shear assessment of slabs are formulated, and used to verify the shear capacity of 10 cases of slab bridges. This “Quick Scan” approach is compared to the AASHTO provisions, which are found to be less conservative. However, the underlying target reliability index is significantly smaller for the AASHTO provisions. For the existing bridges in the Netherlands, the proposed method can analyze a large number of cross-sections and thus help prioritize the efforts f the owners such that cases which need a more detailed shear analysis are identified.