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As structural engineers, we routinely design reinforced concrete members to resist the required loads, and we generate construction documents showing concrete sections with the reinforcing bars in their final configurations. That is, we graphically depict the reinforcing bars as embedded in the hardened concrete, with no formwork or bar supports indicated.
Although we don't show bar supports on our details, our instructions in the general notes may require the contractor to "Provide adequate bolsters, hi-chairs, or support bars to maintain specified clearances for the entire length of all reinforcing bars." Also, our specification for concrete reinforcing (Division 3 of the project manual) will probably require that bars are supported in compliance with the ACI Detailing Manual 1 or the CRSI Manual of Standard Practice.2 Rarely, however, will we place any explicit requirements on how reinforcing bars or bar mats are to be supported, as these concerns are within the domain of the contractor-means and methods.
While polymer, wire, or precast concrete bar supports are commercially available for use in members up to 10 in. (250 mm) thick, reinforcing bar assemblies, known Using Standees as "standees," are normally required for the support of top mats of reinforcing bars in thick concrete members, such as footings and slabs. Standees are readily available as a standardized product up to 18 in. (457 mm) in height, but various sizes and configurations of standees have also been used in thick mat footings as deep as 12 ft (3.7 m).
STANDEE TYPES
Figure 1 illustrates four common types of standees. Bend Types 25 and 26 are found in Fig. 10, Typical Bar Bends, in the ACI Detailing Manual.1 Bend Type 26 standees are the most commonly used. Shape 27 is a modified Bend Type 26 used by some fabricators, especially near slab edges. Note that all three of these standee types are multiple-plane bent bars (that is, they do not lie flat) and thus are termed "special fabrication" in the industry.
Shape S6 is used in some areas of the country and is a modified version of Bend Type S6 found in Fig. 10 of the ACI Detailing Manual.1 The dimensions "A" and "G" on...