Hello,
ACI 318-19 has changed section 25.4.3 substantially (Development of standard hooks in tension) and made moment transfers from grade beams to caissons a bit more challenging. Is the following approach reasonable or too conservative?
Let's say I have a 200 ft-k of moment to be transferred to the caisson. This moment can be converted to a couple with and arm of 9.75".
3.375" (centroid of the 5 right hand side rebars) + 6.375" (centroid of the left half of the concrete)
200x12/9.75= 246k or 246/(.9x60)= 4.56 sq.in. of rebar. I have 5x1.27=6.35 sq.in. so rebar is OK.
In the best case scenario I will need to develop #10 rebars 22", doable, or in the worst case 22x1.6x1.2=42", not doable.
Has anyone faces a similar situation? Any comments or suggestions will very much appreciated.
Thank You,
Vic.
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1679277839/tips/Caisson-Q_qq4jrv.pdf[/url]
ACI 318-19 has changed section 25.4.3 substantially (Development of standard hooks in tension) and made moment transfers from grade beams to caissons a bit more challenging. Is the following approach reasonable or too conservative?
Let's say I have a 200 ft-k of moment to be transferred to the caisson. This moment can be converted to a couple with and arm of 9.75".
3.375" (centroid of the 5 right hand side rebars) + 6.375" (centroid of the left half of the concrete)
200x12/9.75= 246k or 246/(.9x60)= 4.56 sq.in. of rebar. I have 5x1.27=6.35 sq.in. so rebar is OK.
In the best case scenario I will need to develop #10 rebars 22", doable, or in the worst case 22x1.6x1.2=42", not doable.
Has anyone faces a similar situation? Any comments or suggestions will very much appreciated.
Thank You,
Vic.
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1679277839/tips/Caisson-Q_qq4jrv.pdf[/url]