Steel Element Failure

Hi Robert, just to clarify, do you mean the steel building designer is saying they designed the steel element (threaded rod/rebar/etc) being anchored into the concrete per AISC? What is the actual steel element being used in this case?

If your project is governed by ACI 318-14, then section 17.4 lays out the method for calculating design strength and comparing the tension failure modes which include steel element in tension, concrete breakout in tension, pullout/bond failure, and side-face blowout. Section 17.5 similarly lays out design strength calculations for the shear failure modes which include steel element in shear, concrete edge breakout, and pryout. The lowest capacity failure mode in tension and shear are considered your governing failure modes, and these are compared to your factored loads. If your factored loads are equal to or less than the governing design strengths in tension and shear, they will now have to pass the interaction check in section 17.6. All of this is assuming that you meet the requirements for edge distance, spacing, and concrete thickness in Section 17.7 and installation parameters in section 17.8.

The Engineer of Record (EOR) for the project could compare the capacity calculated for the steel element per AISC versus the design strengths calculated per ACI 318-14 Chapter 17. Ultimately it is up to the EOR to judge whether the calculation is adequate for the projects needs.

If you have further questions, please email our Technical Services team with specific details at deck@hilti.com.

Thanks,
Adam