Can embeds in columns be considered as uncracked concrete?
*Posted on behalf of a Hilti customer.
Hi Customer,
thank you for reaching out to us. Concrete cracks when tensile stresses in the concrete imposed by loads or restraint conditions exceed its tensile strength. Concrete is typically assumed to crack under normal service load conditions. Crack width and distribution are generally controlled through the use of reinforcement. With consideration for the protection of the reinforcing steel, crack widths are assumed to be less than approximately 0.012 in (0.3 mm). Under seismic loading, flexural crack widths corresponding to the onset of reinforcing yield are assumed to be approximately 1-1/2 x static crack width = 0.02” (0.5 mm). Both ACI 318 and the International Building Code assume cracked concrete as the baseline condition for the design of cast-in-place and post-installed anchors since the existence of cracks in the anchor vicinity can result in a reduced ultimate load capacity and increased displacement at ultimate load compared to uncracked concrete conditions. Design for uncracked concrete conditions is permitted only for cases where it can be shown that cracking of the concrete at service load levels will not occur over the anchor service life. Don't hesitate to contact us if there is anything else we can do for you.
All the best
jerrod