Plastic Bar Chair. Used in the construction material.AS NZS
Plastic slab-on-ground spacers are suitable for supporting both reinforcing mesh and bar in slab-on-ground applications.
Slab-on-ground spacers are made to cover two heights These bar chairs are a dual-size plastic reinforcing They have a flat base to minimise penetration through the waterproof membrane The bar chairs are supplied stacked in the bag to minimise storage spaceAccording to AS3600, cover is the distance between the outside of the reinforcingsteel or tendons and the nearest permanent surface of the member, excluding anysurface finish.
The two primary purposes of cover are durability and fire resistance. As a generalrule, cover is selected from an appropriate table but there are several cases whereadditional cross checks are required.
A secondary reason for adequate cover is to ensure that the stresses in steel andconcrete can be transferred, one to another, by bond. These actions are calledstress development and anchorage. The cover required for these purposes ismeasured not to the nearest bar, but to the bar whose stress is being developed.
Slab on ground plastic bar chair