Re: Transfer force of large tie beam

Last I heard, grade 40 was a fractional cent per pound less than grade 60, so I'm not sure theres much economy there. 60 kips is only, what, about 4 number 6 bars for strength? I haven't done a PEMB with forces this large recently, so I can't give any specifics on details. If it were me, I would just check every material interface from the baseplate down to make sure there were no weak spots.

Jordan

Rich Lewis wrote:

I have a pre-engineered metal building with some large tie beam forces.  They are around 60 kips.  The reason they are so high is a 40 psf roof snow load with a 13 feet eave height.  The clear span of the rigid frame is 80 feet.  For smaller loads I typically wrap the anchor bolts with a ‘U’ shaped rebar and use mechanical ties for the rebar of the tie beam.  With loads this high I was wondering if I should be using a better mechanism for transferring the forces.  What other options might I consider to transfer the thrust force from the rigid frame to the tie beam?  I’m also wondering about stretching the tie bar itself.  This is a metal frame with metal siding.  What kind of limit should I use as a maximum stretch of the bars?  Should I consider using lower strength steel and a larger area in order to reduce the delta from the PL/AE stretch?

 

Thanks.

 

Rich