PROFIS ENGINEERING
Shear Load Parallel to Two Edges- Summary
Figure 4.5.3.
Reference
Figure 4.5.3 [ 33 ]. It shows the design assumptions for considering shear concrete breakout strength when a shear load acts parallel to two fixed edges( x- and x + edges for this example). ACI 318 shear concrete breakout strength calculations assume failure occurs in the direction of the applied shear load, at the fixed edge being considered. Reference, for example, ACI 318-19 Section 17.7.2. Shear load acting parallel to an edge does not act directly towards that edge; however, there is an influence on that edge with respect to a possible concrete breakout failure. Therefore, ACI-318 calculations for shear concrete breakout parallel to a fixed edge treat the application as if the shear load acts towards the edge, but the calculated nominal concrete breakout strength( V cb( g)) is doubled as a means to consider the less severe condition of load acting parallel to the edge. Reference, for example, ACI 318-19 Section17.7.2.1( c).
For the example shown in Figure 4.5.3 [ 33 ], and discussed in detail in Shear Load Parallel to the x- Edge( page 31) and Shear Load Parallel to the x + Edge( page 32), shear concrete breakout was calculated per ACI 318 provisions for shear parallel to a fixed edge. The shear load( V ua) acts parallel to the x- fixed edge and the x + fixed edge.
With respect to the x- edge, a complete concrete breakout failure surface could develop from both col 1 and col 2. A nominal concrete breakout strength( V cbg, col n) was calculated with respect to each column based on a projected failure area( A vc, col n) at the x- edge.
With respect to the x + edge, a complete concrete breakout failure surface could only develop from col 2. A nominal concrete breakout strength( V cbg, col 2) was calculated with respect to a projected failure area( A vc, col 2) at the x + edge.
The shear concrete breakout provisions for this example are satisfied if V ua, x, col n / ϕ( V cbg, col n) ≤ 1.0 for each case being considered. The maximum utilization [ V ua, x, col n / ϕ( V cbg, col n)] controls the design.
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