PROFIS ENGINEERING
Reference Figure 4.4.3( a) [ 24 ]. It shows the parameters that will be considered with respect to shear load distribution. The shear load V ua acts at an angle with respect to the x- and y- edges. The unequal spacing between rows and columns creates an unequal load distribution on the anchorage. The V ua-component acting towards the x- edge is denoted V ua, x and the V ua-component acting towards the y- edge is denoted V ua, y. Each of these components is distributed on the anchors as shown in Figure 4.4.3( a) [ 24 ]. The load acting on each anchor is designated V ua, x, anchor number for the x- component and V ua, y, anchor number for the y- component. For this example, the shear load component that acts parallel to the x- edge equals V ua, y. Therefore, when considering shear concrete breakout parallel to the x- edge, concrete breakout design strength is calculated with respect to anchor columns( ϕV cbg, col n), but checked versus the shear load component acting parallel to the x- edge on each column( V ua, y, col n). In other words, the shear load( V ua, y) must be considered as if it acts towards the x- edge( instead of towards the y- edge), and as if it is distributed among the anchor columns( instead of among the anchor rows). Reference( e. g.) ACI 318-19 Section 17.7.2.1( c) for shear parallel to an edge provisions.
The parallel shear load( V ua, y, col n) acting on each column could be assumed as follows:
• col 1: V ua, y, col 1 = V ua, y, 1 + V ua, y, 5 + V ua, y, 9 + V ua, y, 13
• col 2: V ua, y, col 2 = V ua, y, 2 + V ua, y, 6 + V ua, y, 10 + V ua, y, 14
• col 3: V ua, y, col 3 = V ua, y, 3 + V ua, y, 7 + V ua, y, 11 + V ua, y, 15
• col 4: V ua, y, col 4 = V ua, y, 4 + V ua, y, 8 + V ua, y, 12 + V ua, y, 16
However, ACI 318 provisions assume V ua, y is distributed proportionately among each column. Figure 4.4.3( b).
Reference Figure 4.4.3( b) [ 25 ]. It shows the parameters that will be considered with respect to concrete breakout failure parallel to the x- edge. ACI 318 provisions for shear load acting parallel to the edge assume the load acts towards the edge, but the calculated concrete breakout strength is doubled. For this example, the concrete breakout failure surfaces will therefore be assumed to develop from each anchor column, and concrete breakout assumed to occur at the x- edge. Based on the spacing between columns, ACI 318 provisions could be extrapolated as shown below.
Consider Case 1 / Case 2
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