Baseplate thickness
Baseplate thickness
(OP)
I am designing a column with a fixed base. Service moment is in the 540 k-ft range. The baseplate thickness is getting to be very large in the order of 3 1/2''. I am considering adding stiffners to increase the section modulus of the base plate.
As far as sizing the weld and considering the shear flow,but the base plate connection is almost purly moment so having a hard time sizing the weld of the stiffner to the baseplate.
I have sized the vertical column to stiffner connection length based on the bolt eccentricity and shear with respect to the end column flange.
Does any one have a good reference or on advice on how to make sure the weld between the base plate and stiffner is sufficient to consider the stiffner a part of the section of the plate in order to reduces its thickness.
I have already looked in the AISC design guide and have had no such luck with stiffners being added to reduce baseplate, which is a red flag to me.
Regards
As far as sizing the weld and considering the shear flow,but the base plate connection is almost purly moment so having a hard time sizing the weld of the stiffner to the baseplate.
I have sized the vertical column to stiffner connection length based on the bolt eccentricity and shear with respect to the end column flange.
Does any one have a good reference or on advice on how to make sure the weld between the base plate and stiffner is sufficient to consider the stiffner a part of the section of the plate in order to reduces its thickness.
I have already looked in the AISC design guide and have had no such luck with stiffners being added to reduce baseplate, which is a red flag to me.
Regards






RE: Baseplate thickness
RE: Baseplate thickness
RE: Baseplate thickness
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RE: Baseplate thickness
I was able to find a triangular bracket design in my steel book to help provide some checks on my design.
Thanks,
RE: Baseplate thickness
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: Baseplate thickness
RE: Baseplate thickness
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: Baseplate thickness
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: Baseplate thickness
As far as the final decision I did go with the stiffned base plate but when i took a summation of the volumne of plate used, their is not much savings but it is a stronger connection. I still ending up using a 1 1/2 plate w/ 3/4 stiffners for the final detailed connection.
Regards
RE: Baseplate thickness
RE: Baseplate thickness
Second thoughts: If the base plate gets to be thicker than Koot's 2" inch number, extend the bolts up to the top and make a "chair" out of the stiffeners. That way you can keep the stiffeners close together and keep the top plate to a reasonable size. If you try to just stiffen the base plate, your stiffeners will want to be close together to help the base plate, but too close and you can't get a wrench on the bolts. If you really don't want to go with chairs, you figure out the pressure under the plate and consider the plate as supported on three sides.
Third thought: An older engineer once told me to keep the bolt diameter and the plate thickness close to the same size. That seems to optimize things and keep them "looking right".
RE: Baseplate thickness
I've roughed up some half-assed strut and tie or tension field type models in this situation before that I'm comfortable were conservative, but I don't think I've ever seen anything written down about this.
RE: Baseplate thickness
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.