PROFIS ENGINEERING
Shear Load Evaluation – One Load Direction – One Fixed Edge
Figure 6.1.1.
Reference Figure 6.1.1 [ 48 ]. 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 1 / Case 2 are relevant for those two rows. The design shear concrete breakout strength for each of these rows( ϕV cbg, row n) is calculated using the edge distance in the direction of V ua for each row( c a1, row n), and checked versus the shear load assumed to act on each of these rows( V ua, row n). V ua is assumed to be distributed proportionately between all anchor rows resisting shear load. MAX {( V ua, row n /( ϕV cbg, row n)} controls the design with respect to concrete breakout at the y- edge.
For the anchorage shown in Figure 6.1.1 [ 48 ], assume s y, 12 ≥ c a1, row 1 and s y, 23 ≥ c a1, row 1. Case 1 / Case 2 are relevant for rows 1, 2 and 3. Shear concrete breakout calculations are as follows:
•
ϕV cbg, row 1 is calculated using c a1, row 1( orange shaded area)
• ϕV cbg, row 2 is calculated using c a1, row 2( yellow shaded area)
• ϕV cbg, row 3 is calculated using c a1, row 3( green shaded area)
The number of anchors in each row is equal( 4-anchors per row); therefore, V ua for each row is calculated as follows:
V row, i = V total ⋅ i
N rows
• V ua, row 1 =( V ua)( 1 / 3)( acts on anchor 1, anchor 2, anchor 3 and anchor 4)
• V ua, row 2 =( V ua)( 2 / 3)( acts on anchor 5, anchor 6, anchor 7 and anchor 8)
• V ua, row 3 =( V ua)( 3 / 3)( acts on anchor 9, anchor 10, anchor 11 and anchor 12)
The design is satisfied with respect to shear concrete breakout at the y- edge if: MAX( V ua, row1 / ϕV cbg, row 1):( V ua, row 2 / ϕV cbg, row 2):( V ua, row 3 / ϕV cbg, row 3) < 1.0
Shear Load Evaluation – One Load Direction – One Fixed Edge( page 49) explains how V ua is calculated when s y, nn < c a1, row 1
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