We are involved with a project which requires that anchorage of some steel plates to the underside of a concrete slab on metal deck (B-Deck). The relative location of the plate to the deck ribs will vary and to get the holes to consistently align with the ribs will be challenging. The loads being resisted are tension only (no shear). Would it be permissible to install Kwik Bolt TZ anchors in areas of the high ribs whereby a portion of the anchor would not be embedded in concrete (see attached image)? If this is permissible, could we then use the load values for Figure 4 (W-Deck) even though the deck being utilized is a B-Deck (Figure 5)?
Hi Thomas,
Stand-off conditions for anchoring to concrete-over-metal deck applications is outside the scope of Hilti’s testing and PROFIS Engineering software. The PROFIS Engineering software has the ability to evaluate certain stand-off conditions in the anchoring-to-concrete module, which introduces bolt bending analysis via the shear steel failure with lever arm calculation. Currently, there are no test standards in North America for bolt bending. The shear steel failure with lever arm calculation comes from ETAG 001, Annex C Part 4.2.2.4, and it is not directly referenced in the ACI 318-14 Chapter 17 anchoring-to-concrete provisions. You could consider using this as a guide when evaluating for bolt bending conditions.
Regards,
Paris
Tom,
Since the application is for a different deck type than shown in Figure 4, the engineer on the project should consider engineering judgment and on-site evaluation to determine suitability for the application.
Regards,
Paris