Stamping plans for welded Ibeam building? 1

[Bradley5]

We are looking to construct a building for ourselves and was leaning towards a PEMB building but delays from manufacturers are creating some issues. We are in talks with a company that basically uses off-the-shelf beams, cut and weld onsite. I'm simply baffled how they do this with no engineered plans at all!? We are, however, somewhat considering these guys in our project but we would have to properly design and stamp plans. We have never evaluated such construction but do engineered plans for wood post frame, wood conventional, and PEMB foundations.

I'd be curious if anyone here has evaluated such a building?

 

[XR250]

Regarding the building, 60x100x18, 2:12 pitch, 25ft bays, 15# sn

No way would I go weld on-site for a building of that scale.

 

[Ron247]

Regarding the building, 60x100x18, 2:12 pitch, 25ft bays, 15# snow, 20# live, 112 wind ASCE-7. We have plenty of knockdowns on snow and live. Primary driver is wind, both lateral and uplift considerations. Well, I say that but haven't gone to work on hard numbers yet.

Also considering going to an 80x100x18, and install a centered column under each of the 3 portal frames to see if we could knock down some of the steel requirements. The design idea/goal was if we could drive material costs of the 80W down below the 60W freespan, the numbers start looking appealing to get more sf in the space.

A metal building of those clearspans could be reasonably done with mill steel. Tapered members are not that efficient on shorter spans. As far as welding purlins to frames, if they are using cold-formed purlins, the thin member sizes (.06" to .07" lets say) may be hard to weld good to thicker flanges. That whole thick versus thin thing. May be better to bolt to flange or add a clip.

 

[Bradley5]

A metal building of those clearspans could be reasonably done with mill steel. Tapered members are not that efficient on shorter spans. As far as welding purlins to frames, if they are using cold-formed purlins, the thin member sizes (.06" to .07" lets say) may be hard to weld good to thicker flanges. That whole thick versus thin thing. May be better to bolt to flange or add a clip.

Ron, the guys that are welding these are indeed welding pros with plenty of credentials. As for the purlin attachments, they do weld them to the beam flange, but also add a 6" triangle clip.

Just because I have the time right now, I am running some math on the building and I think we can make it work, and currently looking at w18x35 beam. As well, I am checking that as easily good so I am considering pushing the rafters a bit longer(wider building) to sort of make best use. I was trying to get w16x26 to work but getting into deflection issues on the rafters and trying to stick around L/240.

I have noted that one PEMB that was quoted to us had wall deflections of H/60-H/90, and in our office area, am and making adjustments for H/240.....So I guess one of the advantages here is we can just design what we want, hand the plan to the welders, and get going.

I think some here think the welders will only build one way. Actually they are more than open to listening and learning. I only wish we had a touch more experience, but we can get it done.

It looks like regardless of anything we do, we will design and require haunches at the top of the columns and the rafter peaks. Possibly even quite long up the rafter to smooth out some loads and manage deflections. We are also evaluating much higher wind pressures than code requirements.