Product Technical Guides : US-EN Cast-In Anchor Channel Fastening Technical Guide | Page 164

1. Anchor Channel Systems 2. HAC Portfolio 3. HAC Applications 4. Design Introduction 5. Base material 6. Loading Anchor Strength, фN sa ϕ N sa ≥ N aua where A se,N is the effective cross-sectional area of an anchor in tension, in. 2 , and f uta shall not be taken greater than the smaller of 1.9f ya and 125,000 psi. Anchor Strength of Connection Between Anchor and Channel фN sc ϕ N sc ≥ N aua The connection between anchor and channel strength N sc , and ϕ is tabulated in Table ESR-3520 Table 8-3 for HAC and HAC-T with Hilti Channel Bolts (HBC-C, HBC-T and HBC-C-N). 14. Design Example Conduct of tests (locking channel bolts in combination with nonserrated channels and serrated channels in combination with matching serrated channel bolts): ϕN sl ≥ N aua The Test No. 2 of AC232 is performed to determine the strength of local rupture of the channel lips. Test No. 2 the anchors shall be tested in a tension test rig without being cast into concrete (See Figure 7.3.1.2). Insert the channel bolt over one anchor and apply the load directly to channel bolt without a fixture. Figure 7.3.1.2 — Tension test setup for testing anchor channels in a universal testing machine. (Figure taken from AC232, Figure 5.5). The failure load, the corresponding displacement, and the failure mode shall be recorded. Figure 7.3.1.3 — Test setup for tests in accordance with table 4.1 of AC232, test No. 5. (Figure taken from AC232, Figure 7.1) Figure 7.3.1.1 — Tension test for testing anchor channels in a universal testing machine. Exception: In Test No. 2 (determination of the channel lip strength) tests shall be performed with anchor channels with two anchors cast into low-strength concrete with anchor spacing s > s min where s min , shall be taken as the value which will be published in the ICC-ES Evaluation Service Report but shall not be taken less than 4 inches (100 mm). The distance between the end of the channel and the anchor axis shall correspond to the minimum value specified for the tested channel size. Insert the channel bolt over one anchor and apply the load directly to the channel bolt. A fixture with the following dimensions shall be used: width = b ch length = 3b ch , thickness = d f . The fixture shall be shimmed with steel strips having a thickness = 1/8 inch (3.2 mm) located on each side of the anchor channel as shown in Figure 7.3.1.3 below. The diameter of the hole in the fixture shall be approximately 10 percent larger than the diameter of the shaft of the channel bolt. The channel bolt shall be pre- tensioned. However, the support spacing may be reduced to 1.0 h ef in every direction as shown in Figure 7.3.1.4. Direct contact between the test stand and the channel profile is not permitted. The average load factor of 1.4 (from 1.2D + 1.6L) divided by the highest ϕ-factor (0.75 for tension) results in a limit of f uta /f ya of 1.4/0.75 = 1.87. Although not a concern for standard structural steel anchors (maximum value of f uta /f ya is 1.6 for ASTM A307), the limitation is applicable to some stainless steels. 13. Field Fixes The Test No. 1 of AC232 is performed to determine the strength of the connection between anchor and channel. All anchor channel sizes with all anchor types and all materials are tested. The largest channel bolt with the maximum steel strength specified for the tested anchor channel shall be used as a component of the test specimen to avoid failure of the channel bolt. The anchors shall be tested in a tension test rig without being cast into concrete. Insert the channel bolt over one anchor and apply the load directly to channel bolt without a fixture. Channel lip strength N sl , and ϕ is tabulated in Table ESR-3520 Table 8-3 for HAC and HAC-T with Hilti channel bolts (HBC-C, HBC-T and HBC-C-N). 12. Instructions for Use The nominal strength of anchors in tension is best represented as a function of f uta rather than f ya because the large majority of anchor materials do not exhibit a well-defined yield point. The limitation of 1.9f ya on f uta is to ensure that, under service load conditions, the anchor does not exceed f ya . The limit on f uta of 1.9f ya was determined by converting the LRFD provisions to corresponding service level conditions. Channel Lip Strength фN sl 11. Best Practices N sa = A se,N f uta 10. Design Software The nominal strength N sa , of a single shall be computed in accordance with Section 17.4.1.2 (ACI318-14) as shown below. 9. Special Anchor Channel Design Anchor strength N sa , and ϕ is tabulated in Table ESR-3520 Table 8-3 for HAC and HAC-T with Hilti channel bolts (HBC-C, HBC-T and HBC-C-N). 8. Reinforcing Bar Anchorage 7.3.1 STEEL TENSILE STRENGTHS 7. Anchor Channel Design Code 164 Cast-In Anchor Channel Product Guide, Edition 1 • 02/2019 165 Figure 7.3.1.4 — Example of an unconfined tension test setup for testing anchor channels (Figure taken from AC232, Figure 5.4).