PROFIS ENGINEERING
For rows 1 and 3, assume s x12 < 3c a1, row 1 and s x23 < 3c a1, row 1. For row 2, assume( s x12 + s x23) < 3c a1, row 1. Therefore, the anchors in each of the three rows act as a group with respect shear concrete breakout calculations( e. g. reference ACI 318-19 Section 17.5.1.3.1).
Assume s y, 12 is less than c a1, row 1 and s y, 23 is greater than c a1, row 1. Case 3 will be considered with respect to row 1 and row 2. Case 1 / Case 2 will also be considered with respect to row 1 and row3.
Figure 4.3( a).
Reference
Figure 4.3( a) [ 16 ]. When considering Case 3 for rows 1 and 2, assume a concrete breakout failure surface will only develop from row 1, disregarding concrete breakout from row 3, so the total shear load( V ua) is assumed to act only on the anchors in row 1. This is a conservative assumption. The design premise being that the merging of the concrete breakout failure surface from row 2 with that of row 1 negates consideration of concrete breakout from row 3.
V ua, row1 = 1.0 V ua design is satisfied if( V ua, row1 / ϕV cbg, row1) < 1.0
Figure 4.3( b).
Reference Figure 4.3( b) [ 16 ]. When considering Case 1 / Case 2 for rows 1 and 3, V ua is assumed to be distributed proportionally between these two rows, so( 0.5V ua) is assumed to act on row 1 and( 1.0V ua) is assumed to act on row 3. This is a reasonable assumption based on ACI 318 criteria for considering Case 1 / Case 2. The design premise being concrete breakout failure should be considered with respect to any anchor row / column from which a complete concrete breakout failure surface could develop.
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