When I run an analysis on six threaded rods in two columns and three rows at 16" on center, Profis output indicates a spacing reduction factor of 0.579. When I look at ICC-ES ESR-4143, Tables 3A and 3B I get an interpolated reduction factor of 0.76. Are we supposed to use a spacing reduction factor for vertical and horizontal spacing so that the actual reduction factor for spacing with 16" on center horizontal and vertical is 0.76*0.76=0.579? If this is correct, it is not clear in the documentation that the spacing reduction factor has to be the product of horizontal and vertical spacing reduction factor.
Hi Barry,
Per ESR-4143, Tables 3A and 3B, Footnote 6 states that load reduction factors are multiplicative. When creating a PROFIS Engineering example with the below parameters, the software specifies the most utilized anchor on page 4 of the design report. In the attached sample, Anchor 1 is the most utilized and would have spacing reduction factors due to the influence of Anchors 2 (horizontal) and 4 (vertical). For a ¾” threaded rod with HIT-HY 270 spaced 16” o.c., the reduction factors are 0.7609*0.7609 = 0.58 (to match PROFIS Engineering).
Best,
Sam
