enfsgi
Structural
- Sep 19, 2011
- 8
The equation for Avo is based on a large concrete section and uses the edge distance to calculate the area. Looking at a foundation such that the edge distance is very large compared to the depth. In calculating Av it will be limited by this depth. Thus the ratio of Av / Avo used in eq. D-20 or D-21 will be small, reducing the anchor(s) nominal strength. In the commentary text is a mention that for large edge distances the concrete failures will probably not govern.
Is it legitimate to limit Avo by using the depth (h) as the vertical component of the area instead of the edge distance (1.5c1)? Or is this check not necessary as suggested in the commentary?
ex. 10'x10'x18" footing. c1 is about 60", h = 18". D-22 --> Avo = 16200 sq in. Av = 3240 sq in [ig RD.6.2.1(b)] Thus Av / Avo = 0.2
Is it legitimate to limit Avo by using the depth (h) as the vertical component of the area instead of the edge distance (1.5c1)? Or is this check not necessary as suggested in the commentary?
ex. 10'x10'x18" footing. c1 is about 60", h = 18". D-22 --> Avo = 16200 sq in. Av = 3240 sq in [ig RD.6.2.1(b)] Thus Av / Avo = 0.2