Special Inspections of Concrete Reinforcing Steel

Codes and Standards Cited in this Article: International Building Code (IBC); ACI 318 Structural Concrete Building Code; ACI 301 Specifications for Structural Concrete; ACI 117 Specifications for Tolerances in Concrete Construction; Concrete Reinforcing Steel Institute (CRSI)

Determining the particular building code or standards that provide code-required acceptance criteria for special inspections on concrete reinforcing steel can be daunting, to say the least. All the codes and standards appearing in the “Codes and Standards Cited in this Article” list above specify concrete rebar compliance criteria that the special inspector should observe.

ACI 318 stipulates various concrete cover parameters in Chapters 20 and 25, and Chapter 26 sets forth code-acceptance criteria for rebar spacing, hooks, bends, stirrups, and rebar placement tolerances. ACI 301, Section 3, lists page after page of code compliance criteria ranging from rebar splices and dowels to type of steel and grade of reinforcing bars. ACI 301 is adopted by almost every project concrete specification in the land and is the foundation of all concrete specification sections of the contract documents. Recent versions of ACI 301 typically mirror the same general requirements and criteria as the concrete code (ACI 318). ACI 117 was recently adopted by the IBC code and is the “Specification for Tolerances for Concrete Construction.”

ACI 318, Section 26.4.2.1 (a) (5), cited in the narrative box at the bottom of the page, specifies the nominal maximum size of coarse aggregate in the concrete to be placed in rebar schemes. The size is critical for ensuring that voids or honeycombing do not weaken the concrete element. Section 26.4.2.1 represents a popular “rule of thumb” regarding concrete/rebar placement and inspections, but the narrative is difficult to locate within the hundreds of pages of code verbiage related to rebar inspection criteria. Practically every project concrete specification requires reinforcing steel to be placed and secured in accordance with the Concrete Reinforcing Steel Institute (CRSI). A plethora of vital compliance criteria are presented in the CRSI standards.

ACI 318, Section 26.4.2.1 (a) (5)

Nominal maximum size of coarse aggregate not to exceed the least of (i), (ii) and (iii).

(i)?one-fifth the narrowest dimension between sides of forms

(ii)?one-third the depths of slabs

(iii) three-fourths the minimum specified clear spacing between individual reinforcing bars or wires, bundles of bars, prestressed reinforcement, individual tendons, or ducts

For more information or further enthusiastic discourse on topics of CODE, please contact Alan Tuck at: [email protected] or 540.344.7939