Combining Welds and Bolts in a built-up beam
Combining Welds and Bolts in a built-up beam
(OP)
Hello,
For various dimensional reasons I need to create a built-up beam. I have a W16x36 --below it is a W18x40 and the loads are applied to the lower flange of the W18 beam. I have calculated the required fillet weld to handle the transverse shear as calculated from SCM eq 1-1 (pg.1-7 SCM14). I can weld around the flange of the smaller beam to the larger beam. However, I would be concerned about the flanges flexing under loading and causing rotation at the weld root. Therefore I am proposing using the weld to handle the transverse shear and bolts spaced every 14 inches to handle the direct shear and prevent flexing of the flanges about their weld roots.
Bolts alone are not a good options as they have to be SC due to reversing load conditions. I would need a large amount of bolts.
I attached a graphic. What are your thoughts? Is this a sound approach?
Thanks
For various dimensional reasons I need to create a built-up beam. I have a W16x36 --below it is a W18x40 and the loads are applied to the lower flange of the W18 beam. I have calculated the required fillet weld to handle the transverse shear as calculated from SCM eq 1-1 (pg.1-7 SCM14). I can weld around the flange of the smaller beam to the larger beam. However, I would be concerned about the flanges flexing under loading and causing rotation at the weld root. Therefore I am proposing using the weld to handle the transverse shear and bolts spaced every 14 inches to handle the direct shear and prevent flexing of the flanges about their weld roots.
Bolts alone are not a good options as they have to be SC due to reversing load conditions. I would need a large amount of bolts.
I attached a graphic. What are your thoughts? Is this a sound approach?
Thanks






RE: Combining Welds and Bolts in a built-up beam
RE: Combining Welds and Bolts in a built-up beam
RE: Combining Welds and Bolts in a built-up beam
RE: Combining Welds and Bolts in a built-up beam
RE: Combining Welds and Bolts in a built-up beam
Dik
RE: Combining Welds and Bolts in a built-up beam
My thought is that your proposal is a brilliant solution to an issue that has always concerned me. Moreover, since your bolts are not actually going to be carrying any shear, I see no requirement for slip critical.
It appears that only your upper beam will make it to the support. That being the case, you'll need concentrated hanger capacity near the end of the beam in addition to uniform hanger capacity along the length of the beam. Based on all the stiffener voodoo that you're showing in your sketch, I'm guessing that you've already got that covered and I'm preaching to the choir.
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: Combining Welds and Bolts in a built-up beam
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: Combining Welds and Bolts in a built-up beam
You can't really use the bolts in slotted holes (in an attempt to not take shear and also further separate the bolts and welds into two different connections, but I'm not sure how practical this would be as you'd need pretensiioned bolts in this tension connection - so no easy slip behavior.
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RE: Combining Welds and Bolts in a built-up beam
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: Combining Welds and Bolts in a built-up beam
RE: Combining Welds and Bolts in a built-up beam
Dik