SiC BLAST – Concrete Anchors & IBC

concrete anchors and ibc 1705.3

Regarding special inspections on cast-in-place concrete anchors and post-installed concrete anchors, there has been a lot of confusion over the last few IBC building code cycles and it is very understandable. The reference to special inspection of anchors cast in concrete (where allowable loads have been increased OR strength design is used) has been deleted entirely from the IBC code. Most of the confusion over the last decade was the ever changing policies between the “strength design” method (concrete and masonry) and “load and resistance factor design (LRFD) used mostly for steel and wood.  Do not misunderstand; IBC Table 1705.3 in chapter 17 still requires PERIODIC special inspections on anchors cast in concrete (like anchor rods). The reference column in Table 1705.3 cites section 17.8.2 of the concrete code (ACI 318) but section 17.8.2 gives you NO guidance about special inspections for anchor rods; you should review AISC 360, Chapter N, and subsection N5, paragraph 7 which will give you ALL the details about what special inspections to perform on cast-in-place anchor rods in the field.

On the other hand, IBC Table 1705.3 now requires CONTINUOUS special inspections on post-installed adhesive anchors installed in horizontal or upwardly inclined orientations. The difficulty of properly installing adhesive anchors greatly increases when gravity works to drain the epoxy out of the predrilled hole. That is why the installers of adhesive anchors must be certified to do so in accordance with code and ACI requirements.  The best place to review the required special inspections for adhesive anchors is ACI 318, chapter 17, section 17.8 as well as ACI 355.4, section 13.3 (which is far more informative than section 17.8 of ACI 318).