The bending of reinforcement bars Minimum bending pin diameter for bars
The minimum diameter Øm (mandrel diameter) to which a bar is bent, shall be such to avoid bending cracks to the bar and ensure the integrity of concrete inside the bent of the bar where large forces appear. The smaller the mandrel diameter is, the larger these forces are and consequently the concrete may fail thus leading to the disintegration of the cross-section.
Minimum bending pin diameter for wired mesh
Bar anchorage with simple hook
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.
Apart from the satisfaction of the bending standards, the bent section of a bar is accounted in the overall anchorage length lbd (see next paragraph ) when the three following conditions are met:
(1) The anchorage of the bar does not require a length larger than 5Ø beyond the bending point,
(2) At least one transverse bar (metal pins) with diameter ≥Ø is fitted within the bent section,
The bending level is not situated too close to the surface of the concrete.
Beam bar anchorage with simple hooks and 2 welded pins
Beam bar anchorage with simple hooks and 2 welded transverse bars (metal pins) could be ≥0.6Ø within the bent section