A review of design and assessment methods for skew concrete slabs

Concrete slabs are often used for short-span bridges where it is required to limit the deck construction depth. Alongside, skew decks are helpful when there are space con-straints in the bridge construction area, e.g., in urban areas, thus they are not uncommon. Nonetheless, skew slabs are not as much investigated as straight slabs and comprehensive guidance on their design or assessment is generally lacking. This is particularly the case for the shear behaviour of skew concrete slabs, which exhibit significant load concentrations around the obtuse corners with observed failure modes that are intermediate between the traditional cases of one-way and two-way (punching) shear. A reliable estimation of the shear strength is beneficial for both design and assessment: in fact, if shear strength is over-estimated, it may lead to undesired brittle failures, whereas if it is under-estimated, it may lead to inefficient design or unnecessary interventions to existing structures. This paper reviews the provisions of three codes of practice on shear design (Eurocode 2, the Swiss SIA 262, and fib Model Code 2010), as well as main research on skew slabs. Procedures for extending the code provisions to skew slabs are presented and then applied to a case study. Some scatter is found across different codes of practice, broadly reflecting their complexity. The findings may be useful to practitioners with the design and assessment of skew concrete slabs.