Punching Shear Strength of Slabs including Double-Headed Studs (Concrete 2021)

This webinar was recorded at Concrete 2021 and the speaker is Andreas Boomkamp from Leviat.

Double-headed studs are used as punching shear reinforcement in reinforced or prestressed slabs and footings. Due to an improved anchoring behaviour, double-headed studs have a higher load capacity than stirrups. Double-headed studs are quick to install and are therefore more cost-efficient than stirrups. Provided flexural and bond failure is avoided, flat slabs can fail in a local shear failure, the so-called punching shear failure.

It is necessary to distinguish between punching shear failure in slabs with and without shear reinforcement. At present, no commonly accepted design provisions for slabs including double-headed studs as shear reinforcement are available in Australia.

Lim and Rangan proposed a punching shear model for slabs with stud shear reinforcement, based on AS 3600. However, this model was calibrated on only three punching tests on edge column-slab connections and an assessment for the different failure modes was not performed.

This presentation offers a critical comparative review of the design provisions for double-headed studs according to EOTA Technical Report 060, ACI 318-1 9, and the model of Lim and Rangan.