Blackfairy
Civil/Environmental
- Jul 22, 2024
- 5
Hi,
I am checking a 30'x30'x2' footing/slab on grade for a transformer and basically the designer gave me a calc. The minimum S&T 0.0018Ag, he distributed it on half on top and half on bottom which is correct, but since there is Overturning moment due to the center of gravity of the transformer (which is above the top of footing) and seismic, the slab/footing will experience a moment and will need flexure reinforcement. Now regarding minimum flex reinforcement, it is also 0.0018Ag distributed near the tension face, which is at the bottom, this will double the reinforcement on what he has right now. Will this be the right step?
I guess another question i have is, what is the S&T for? I think it is very rare for a footing to not experience moment, and as soon as they have moment the minimum flexure kicks in already which is the same as the S&T, so you can put all the rebars at the bottom and also call it S&T reinforcement because they are the same ratio of 0.0018 minimum.
I am checking a 30'x30'x2' footing/slab on grade for a transformer and basically the designer gave me a calc. The minimum S&T 0.0018Ag, he distributed it on half on top and half on bottom which is correct, but since there is Overturning moment due to the center of gravity of the transformer (which is above the top of footing) and seismic, the slab/footing will experience a moment and will need flexure reinforcement. Now regarding minimum flex reinforcement, it is also 0.0018Ag distributed near the tension face, which is at the bottom, this will double the reinforcement on what he has right now. Will this be the right step?
I guess another question i have is, what is the S&T for? I think it is very rare for a footing to not experience moment, and as soon as they have moment the minimum flexure kicks in already which is the same as the S&T, so you can put all the rebars at the bottom and also call it S&T reinforcement because they are the same ratio of 0.0018 minimum.