Factory bending of rebar is typically performed on computer-controlled equipment programmed to produce bends according to these minimum internal diameters. When rebar is bent on the jobsite, it’s important to use the proper equipment and procedures to avoid damaging the bars. Bending a bar to an internal diameter less than the recommended minimum can produce stresses in the bend zone that can result in bar weakening or failure. Here are a few precautions to take when bending bars in the field.
Don’t use makeshift devices, such as pipes, to bend rebar, It’s difficult to control the internal bend diameter, and a pipe’s sharp edges can notch the bar, weakening it in the bend area.
When using bending equipment, follow recommendations for minimum internal bend diameters for various bar sizes. Don’t try to bend bar sizes or grades that the tool or machine is not designed to handle.
Avoid using impact blows to assist bending. Use of a sledge hammer, for example, can result in over bending of the bar and damage to the rebar surface.
Bending of galvanized rebar can cause flaking of the galvanized coating in the bend area. Repair any damaged coating by applying a zinc-rich paint.
Special precautions are required when bending epoxy-coated bar to prevent coating damage. Bending should only be per formed around a smooth, nonabrasive die to avoid damage to the epoxy coating. If the coating does rub of f in spots, these areas must be repaired. Get approval from the project engineer before attempting to bend epoxy-coated bars.