PROFIS ENGINEERING
Shear Load Evaluation – One Load Direction – One Fixed Edge
Figure 6.1.2.
Reference Figure 6.1.2 [ 49 ]. Assume V ua acts on row 1, row 2 and row 3. Per ACI 318 provisions for shear concrete breakout, if s y, nn < c a1, row 1 for any two adjacent rows, Case 3 is relevant for those two rows. The failure surface for the anchor row farther from the fixed edge being considered is assumed to merge with the failure surface for the anchor row nearer to the fixed edge being considered. The design shear concrete breakout strength( ϕV cbg, row n) is calculated form the anchor row nearer to the fixed edge being considered using the edge distance in the direction of V ua for that row( c a1, row n). The shear load( V ua or a portion thereof) is only assumed to act on the nearer anchor row. ϕV cbg, row n for the nearer row is checked versus the shear load assumed to act on that row.
For the anchorage shown in Figure 6.1.2 [ 49 ], assume s y, 12 < c a1, row 1 and s y, 23 < c a1, row 1. Case 3 is relevant with respect to rows 1, 2 and 3. Shear concrete breakout calculations are as follows:
• failure surface for row 3 merges with the failure surface for row 2( red shaded area)
• no V cbg calculation for row 3
• failure surface for row 2 merges with the failure surface for row 1( red shaded area)
• no V cbg calculation for row 2
• a complete failure surface can only develop from row 1( red shaded area)
• ϕV cbg, row 1 is calculated using c a1, row 1
The total shear load is assumed to act on row 1:
• V ua, row 1 =( 1.0)( V ua) The design is satisfied with respect to shear concrete breakout at the y- edge if:( V ua, row 1 / ϕV cbg, row 1) < 1.0
Shear Load Evaluation – One Load Direction – One Fixed Edge( page 50) explains how V ua is calculated when s y, nn ≥ or < c a1, row 1
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