How many rebars can be bundled, and what must be done about splicing within the bundle?
The ACI Building Code permits bundling of up to 4 rebars provided the bundle is enclosed with stirrups or ties. Bars larger than Number 11 are not permitted to be bundled in beams or girders. Rebars may be butted in flexural members without splicing provided no two butts are closer than 40 bar diameters. For calculating the required spaces between the bundles or between the bundles and the forms, the bundle can be treated as though it were a single bar with the same total equivalent cross-sectional area.