Big Jilm
Structural
- May 1, 2013
- 6
Good Day All,
I've been circling around on this design for a while now. I have read a few of the forum posts on it and done the analysis a couple of different ways. When working with residential, lightly loaded helical piles it has been asserted that the most common execution of these piles is to bypass a reinfirced concrete beam at the bottom of the wall (some might mistake this as a footing) and rely on the 8" concrete wall itself and sink the pile, surveyed into place mid-bm horizontally, and placed vertically with plate 4"-6" into the wall section. I have analysed the members, spaced to a max. of 12-14 feet, and determined that this works in normal beam design. Of course, techinically this would be considered a deep beam. While I'm less confident with my calcs on this, new to me 'strut and tie' method, it also confirmed that essentially, (2)-#5's top and bottom and #5's at 12"o.c. both ways down the middle for an 8"x 36" or 48" depth works just fine in this condition. My question relates to whether or not I should have stirrups instead of vertical bar. Also there is the consideration for 'skin reinforcement' that I'm neglecting in the centered bar design. I am considering going to a mat of (2)-#5's horizontally with #4 stirrups at 12"o.c. which I think is overkill, but would provide a little piece of mind. I recall KootK suggesting something similar in another post and am curious what others do.
Kind Regards,
I've been circling around on this design for a while now. I have read a few of the forum posts on it and done the analysis a couple of different ways. When working with residential, lightly loaded helical piles it has been asserted that the most common execution of these piles is to bypass a reinfirced concrete beam at the bottom of the wall (some might mistake this as a footing) and rely on the 8" concrete wall itself and sink the pile, surveyed into place mid-bm horizontally, and placed vertically with plate 4"-6" into the wall section. I have analysed the members, spaced to a max. of 12-14 feet, and determined that this works in normal beam design. Of course, techinically this would be considered a deep beam. While I'm less confident with my calcs on this, new to me 'strut and tie' method, it also confirmed that essentially, (2)-#5's top and bottom and #5's at 12"o.c. both ways down the middle for an 8"x 36" or 48" depth works just fine in this condition. My question relates to whether or not I should have stirrups instead of vertical bar. Also there is the consideration for 'skin reinforcement' that I'm neglecting in the centered bar design. I am considering going to a mat of (2)-#5's horizontally with #4 stirrups at 12"o.c. which I think is overkill, but would provide a little piece of mind. I recall KootK suggesting something similar in another post and am curious what others do.
Kind Regards,
