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The minimum bending diameter in welded wired meshes is Øm,min=5Ø

Beam bar anchorage with simple hooks and transverse bars (metal pins) ≥Ø within the bent section

The term ‘anchorage’ represents the extension of a reinforcement bar inside the concrete, in order to achieve adequate cohesion of the two materials, steel and concrete. With this specific procedure, steel can contribute up to its maximum strength, whenever it is required. The anchorage can be either straight or hooked.

Beam bar anchorage with simple hooks and 2 welded transverse bars (metal pins) could be ≥0.6Ø within the bent section

Whenever the above requirements cannot be met, then the anchorage is achieved
with a large diameter drum

The minimum bend diameter Øm,min depends on the steel strength fyd, the strength of the con-crete fcd, the diameter Ø of the reinforcement bar and the axial distance ab between the adjacent bars according to the following formula:

• For bar or group of bars near the surface of the structural element ab=cover+Ø/2

• Strength fcd always lower than fcd of concrete class C55/67

In case of anchorage of beam reinforcement bars inside a column (which is the most common case), for common concrete, a_b=37mm+Φ hence the minimum bend mandrel diameter becomes:

Ø_m,min=(PI/4)×ز×f_yd× [1/(37+Ø) + 1/2Ø]/ f_cd

For these cases, the minimum dimensions of the column must be:

l_min=c_nom+ Ø_stir+ Ø + Ø_m,min/2+5Ø

For steel B500c (fyd=434.78MPa) and γc=1.50 and for cnom=35mm, Østir=10mm

Example: For bar Ø20, in case of C20, lmin=380 mm, in case of C30, lmin=310 mm and in case of C40, lmin=270 mm

The minimum bending pin is Ø_m,min

Ø_m,min=4Ø for Ø≤16 mm           Ø_m,min=7Ø for Ø>16 mm