PSI - Issue 84

Alessandro Lipari et al. / Procedia Structural Integrity 84 (2026) 1087–1094

1090

Fig. 2. v x for S60N1Auc.

The design value of the shear stress resistance reads: , = 0 . 6 6 √ 100 3 ≥ ,

(1)

with d dg = 16 + D lower ≤ 40 mm (for concrete with f ck ≤ 60 MPa), or d dg = 16 + D lower (60 / f ck )

2 ≤ 40 mm (for

concrete with f ck > 60 MPa), and , = 1 1 √

in which γ V is the newly introduced partial safety factor for shear and punching resistance without shear reinforcement; ρ = A s / d (for planar members), with A s being the effective area of tensile reinforcement (per unit width) at the distance d beyond the section considered, and d the effective depth; d dg is a size parameter describing the failure zone roughness; D lower , the “smallest value of the upper sieve size D in an aggregate for the coarsest fraction of aggregates in the concrete permitted by the specification of concrete according to EN 206”, which can be replaced by D max , if known; f yd , the design value of the yield strength of steel. The minimum shear stress resistance τ Rdc,min is derived from the general failure criterion of the CSCT, assuming that the reinforcement remains in the elastic range at the maximum possible strain (Muttoni et al., 2023). Eq. (1) implicitly assumes that the effective shear span, a cs , is equal to 4 d . For planar members, it is defined as: = | | ≥ (2) in which m Ed and v Ed are the design bending moment and shear force per unit width. Indeed, for non-slender members with a cs < 4 d , the effective depth d in Eq. (1) may be beneficially replaced by the mechanical shear span, a v : = √ 4 (3) which, in fact, can take the values d /2 ≤ a v < d , thereby increasing the shear stress resistance. For planar members, the calculated shear stress resistance must be verified against the average shear stress over the cross-section τ Ed = v Ed / z , in which z is the lever arm for the shear stress calculation, defined as z = 0.9 d . The structural verification should be carried out using the principal shear force , which is a vector with direction and magnitude: = ( , , ) (4)