Chairs In Raft Foundation

The stiffer the top reinforcement less is the number of chairs required.

Chairs in raft foundation. Spacing of chairs in raft footing depends on its diameter length height and no. The most common type of chair simply suspends the rebar off the ground so that it becomes fully embedded in the concrete as it is poured. Chairs are placed to minimize the bending of top reinforcement due to self weight and to keep the spacing between the top and bottom bars. This is commonly shaped as z or inverted u type reinforcement to evenly separate the top and bottom mesh reinforcement or to provide enough space between the meshes.

Chairs are basically supports that can be made of same reinforcement or other thin material to properly place reinforcement bars in position before concrete is put over. During site construction reinforcement chair or sometimes called as rebar spacer steel chair or simply chair is commonly seen in raft or mat foundations. If external loading like men walking over it is there heavy chairs will have to be placed at close spacings. They are often used on foundation footings concrete slabs and other flatwork.

The chairs may be made of metal or plastic or other non corrosive material.