Hi,
According to ACI 318-19 Section 17.9.3, anchors can be installed at a spacing less than 5 × da, provided they are not torqued. However, for design calculations, a reduced effective diameter must be used to comply with the standard edge distance requirements.
For example, if I install a 1" diameter anchor with a 20" embedment and only 4" from one edge, I would need to consider it as a 7/8" anchor with an effective embedment of 17.5". This is my interpretation of Section 17.9.3.
That said, PROFIS Engineering still uses the full 1" diameter and 20" embedment for all calculations.
How is this discrepancy handled between ACI 318 and the ICC-ES ESR-3814 report?
Hello,
ACI 318-19 Chapter 17 outlines the general design methodology used for anchoring into concrete but allows for more specific properties and provisions if supportive testing is supplied based on ACI 355.2 or ACI 355.4. ICC-ES ESR-3814, for the HIT-RE 500 V3 adhesive anchor, provides supportive documentation on a reduced installation torque in Section 4.1.9 of the report. Section 4.1.9 states “for adhesive anchors that will remain untorqued, ACI 318-19 Section 17.9.3 applies.” The PROFIS Engineering software references the ESR for the anchor that is being modeled; however, the software is limited to adhesive anchors that will be torqued and does not currently have an option for untorqued anchors. Please reach out to hnatechnicalservices@hilti.com for additional questions.
All the best,
Sinan