Posted by Anonymous (user not registered)almost 3 years ago
Hilti HIT-Z and HIT-Z-R shear strength
In the evaluation report ESR-4868, Table 7 (p. 14) for a 1/2" diameter rod:
For the HIT-Z (carbon steel) anchor, Vsa = 5,886 lbs
For the HIT-Z-R (stainless steel) anchor, Vsa = 8,026 lbs
How are these values being calculated and why are the two values different?
2 Replies
Posted by Danielle Fileralmost 3 years ago
Hello,
The shear strengths shown in the ICC ESR are results from testing per the ACI acceptance criteria. Carbon steel and stainless steel have different material properties, which results in different strengths.
Regards,
Dani
1 comment on this reply
Posted by Anonymous (user not registered)almost 3 years ago
Thank you for the response. However, Table 2 of ESR-4868 shows the same material properties for both carbon steel and stainless steel. Per ACI 318-14, Section 17.5.1.2 (as reference in Section 4.1.5 of ESR-4868), Vsa is calculated as Vsa = 0.6*Ase*futa. For a 1/2 inch diameter HIT-Z (carbon steel) anchor, from Table 2 of ESR-4868, futa = 94,200. From Table 7, Ase = 0.1419 in^2. So, Vsa = 0.6 x 0.1419 x 94,200 = 8,020 lb. This does not match the value in Table 7. Can you show how the value in the Table is being calculated? Thank you!
Posted by Danielle Fileralmost 3 years ago
Hello,
As mentioned previously, these values were determined from testing. The equation in ACI does not apply since these values come straight from testing per the acceptance criteria.
Regards,
Dani
1 comment on this reply
Posted by Anonymous (user not registered)almost 3 years ago
I appreciate the response, however, Section 4.1.5 of the report itself (ESR-4868) states the following: The nominal static strength of a single anchor in shear as governed by the steel, Vsa, in accordance with ACI 318-19 17.7.1.2, ACI 318-14 17.5.1.2 or ACI 318-11 D.6.1.2, as applicable and strength reduction factors. . . . are given in the tables outlined in Table 1 for the anchor element types included in this report. The report is stating that the values for Vsa are calculated per ACI, not based on testing as you mention. Basically, Section 4.1.5 of the report contradicts Table 7 of the same report for the case mentioned above. If there turns out to be no good explanation for this discrepancy, then I'll just use the more conservative value. I was just trying to understand the origin of the values in Table 7. Thanks again for any help. Maybe I'll dig around in the anchor design software you offer and see what comes up there.