Portal Frames with Grade Beam vs. Stem Wall
Portal Frames with Grade Beam vs. Stem Wall
(OP)
Here is a detail for a recent project showing some braced wall and portal frame details on top of a stemwall foundation:

After spending some time working through Chapter Thirteen of Terry Malone's book I have tended to shy away from using thickened edge slabs at portal frames and have gone with a stemwall and standard cont. footing instead on most of my residential projects. My thinking is that you cannot get enough stiffness and strength from a shallow thickened edge slab foundation as compared to the depth/section you can achieve with a stemwall foundation.
However, I now have client who does not like the stemwall option and would prefer a more shallow grade beam at the garage doors. As this one is a little new for me I am wondering if there are any caveats I should be aware of and if there is any sort of industry standard or specific software utilized when it comes to the design of grade beams. I will probably end up writing my own spreadsheet for this sort of thing but I always like to have a way of checking my calculations when possible.

After spending some time working through Chapter Thirteen of Terry Malone's book I have tended to shy away from using thickened edge slabs at portal frames and have gone with a stemwall and standard cont. footing instead on most of my residential projects. My thinking is that you cannot get enough stiffness and strength from a shallow thickened edge slab foundation as compared to the depth/section you can achieve with a stemwall foundation.
However, I now have client who does not like the stemwall option and would prefer a more shallow grade beam at the garage doors. As this one is a little new for me I am wondering if there are any caveats I should be aware of and if there is any sort of industry standard or specific software utilized when it comes to the design of grade beams. I will probably end up writing my own spreadsheet for this sort of thing but I always like to have a way of checking my calculations when possible.
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com






RE: Portal Frames with Grade Beam vs. Stem Wall
I normally have a 24" stemwall/gradebeam and at the garage door I drop it to 18.
RE: Portal Frames with Grade Beam vs. Stem Wall
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Portal Frames with Grade Beam vs. Stem Wall
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com