What is the term for the type of hardware that holds reinforcement bars at a specific distance from the form?

The term for the type of hardware that holds reinforcement bars, commonly known as rebar, at a specific distance from the formwork is "chairs." Chairs are used in concrete construction to ensure that the reinforcement bars are properly positioned within the concrete slab or element, allowing for the necessary coverage of the concrete over the bars. This coverage is essential for protecting the rebar from corrosion and ensuring structural integrity.

Chairs come in various designs and heights to accommodate different sizes and spacing of rebar. By using chairs, contractors can ensure that the rebar remains at the correct elevation as the concrete is poured, which is critical for the performance of the finished concrete element.

In contrast, shims are typically used for leveling or adjusting positions of objects but do not specifically hold rebar in place. Supports can refer to various types of structural elements that support loads, but they are not dedicated to holding reinforcement bars at specified distances. Brackets are generally used to connect or support structural elements but don't have a specific role in setting rebar spacing.