French to English Tech/Engineering Construction / Civil Engineering Starter bars for concrete construction

Hi all,

Hope all's well!

I'm translating a construction site welcome pack from French (France) into English (United Kingdom) and am having trouble with the section relating to on-site protective safety systems.

The phrase in question relates to the steel starter beams for concrete construction and shows a starter beam in the shape of a shepherd's crook.

Does anyone know the technical term for this please?

Thanks in advance for your help! :)