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2.1.3 Shear Forces Between Web and Flanges of T-Beams
Shear Forces Between Web and Flanges of T-Beams
The longitudinal shear stress vEd,f at the junction between flange and web is determined by the longitudinal force difference Δ Fd,f in the flange's governing part according to EN 1992-1-1, clause 6.2.4 (3), equation (6.20).
: flange thickness at junction
: longitudinal force difference in flange over length Δx
The maximum value that may be assumed for the length Δ xf is half the distance between the maximum and the zero point of moments. Where concentrated loads are applied, the distance between the concentrated loads should not be exceeded.
The determination of Δ Fd,f is done optionally with a control available in the module details according to two different methods that are described below.
1. Simplified method via inner lever arm z = 0.9d without considering Mz,Ed
for compression flanges
for tension flanges
: distance between centroid of cross-section and tension reinforcement
: lever arm of internal forces 0.9 d
: width of adjacent flange (compression flange) or width of reinforcement distribution in adjacent flange (tension flange) considering the Distribute reinforcement evenly over complete slab width option (see Figure 3.30)
: flange width
: reinforcement exposed in connected tension flange
: total area of tension reinforcement
2. Calculation of Fd from general stress integration in partial areas of cross-section
The required tension flange reinforcement due to shear forces per unit length asf may be determined according to equation (6.21).
1.0 ≤ cot θf ≤ 2.0
: inclination of concrete compression strut for compression flanges
1.0 ≤ cot θf ≤ 1.25
: inclination of concrete compression strut for tension flanges
: design yield strength of reinforcement
At the same time, the compression struts in the flange must be prevented from failing, which is ensured if the following requirement is met:
Equation 2.6 EN 1992-1-1, Eq. (6.22)
: design value of concrete strength
: reduction factor for concrete strength in case of shear cracks