PROFIS ENGINEERING
Band Width Approach for Shear Concrete Breakout- Summary
Figure 5.2.3. Band Width Approach for Shear Concrete Breakout- Summary
Reference
[ 39 ]. The“ band width” approach permits consideration of shear concrete breakout when no two anchors are aligned to form either a row or a column. In [ 39 ], no two anchors align to form a row in the x direction( yellow dashed lines) or a column in the y direction( green dashed lines). Therefore, no two anchors align together such that they are equidistant from either the y- edge or the x- edge.
A length( L) will be defined as the distance in the assumed direction of the shear load( V ua) between the outermost anchors in the anchorage. This length( L) is multiplied by a factor of 0.25 to give a“ band width”. With respect to shear load acting towards the x- edge, the band width would be defined by the parameter 0.25L x. Anchors spaced in the x direction that are located within 0.25L x include anchors 1, 4 and 6. The band width approach treats these anchors as a“ column” defined by the perpendicular spacing between the anchors( L y). This“ column” is assumed to be located a distance c a1, x from the x- edge, which corresponds to the distance of the“ column” anchor nearest to the x- edge( i. e. anchor 1 for this example). Shear concrete breakout( ϕV cbg, x) is calculated per the yellow shaded area. ACI 318 Case 3 provisions apply, so the total shear load in the x- direction( 1.0V ua, x) is assumed to act on the“ column”. Shear concrete breakout provisions with respect to the x direction are satisfied if( 1.0V ua, x / ϕV cbg, x) ≤ 1.0.
With respect to shear load acting towards the y- edge, the band width would be defined by the parameter 0.25L y. Anchors spaced in the y direction that are located within 0.25L y include anchors 1 and 2. The band width approach treats these anchors as a“ row” defined by the perpendicular spacing between the anchors( L x). This“ row” is assumed to be located a distance c a1, y from the y- edge, which corresponds to the distance of the“ row” anchor nearest to the y- edge( i. e. anchor 1 for this example). Shear concrete breakout( ϕV cbg, y) is calculated per the red shaded area. ACI 318 Case 3 provisions apply, so the total shear load in the y- direction( 1.0V ua, y) is assumed to act on the“ row”. Shear concrete breakout provisions with respect to the y direction are satisfied if( 1.0V ua, y / ϕV cbg, y) ≤ 1.0.
If shear load acts in both the x and y directions, the design is satisfied for shear concrete breakout if MAX 1.0V ua, x / ϕV cbg, x; 1.0V ua, y / ϕV cbg, y < 1.0
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