Aci 315-99 supersedes aci 315-92 and became effective August 31, 1999

5.4—Placing reinforcing steel supports
5.4.1 General—Reinforcing steel must be accurately lo-
cated in the forms and firmly held in place before and during
the placing of concrete. Adequate supports are necessary to
prevent displacement during construction and to keep the re-
inforcing steel at a proper distance from the forms. Bar sup-
ports are sometimes specified to be “sufficient in number
and strength to carry properly the reinforcing steel they sup-
port.” The detailer should show bar supports as required.
* 
Bar
supports are detailed for shrinkage-temperature reinforcing
steel in top slabs of reinforced concrete joist construction only
if specifically required in the contract documents.
Bar supports are not intended to and should not be used to
support runways for concrete buggies or similar loads.
5.4.2 Supports for bars in reinforced concrete cast on
ground—Bar supports are detailed for the top bars only in
slabs on grade, grade beams, footings, and foundation mats
4 ft (1200 mm) or less in thickness, in quantities not to ex-
ceed an average spacing of 4 ft (1200 mm) in each direction.
Separate support bars are detailed only if so indicated by the
A/E or on special arrangements with the contractor, as prin-
cipal reinforcement is assumed to be used for support.
Bar supports will be furnished by the reinforcing-steel sup-
plier for bottom bars in grade beams or slabs on ground and
for the bars in singly reinforced slabs on ground only if spe-
cifically required in the contract documents. There are so
many ways of supporting top bars in footings and foundation
*
Suggested sizes, styles, and placing of bar supports are shown in Chapter 3 (Bar 
Supports) of the supporting reference data section.

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