Wood Guys - This a Problem? 4

[azcats]

***I'm wholly unaffiliated with this project***

Driving home over the weekend and saw these condos under construction. Thought the framing was interesting so I stopped for a look.

Any concern with the checks/splits in those cantilevered 4x8s? Or is this already considered in the lumber grading?

 

[KootK]

Of course it's a 4x8 and not two 4x4's. I thought oldestguy was just being a smart ass. You guys either need to view this on a PC rather than your phones or hit the optometrist.

 

[KootK]

That stucco facade has no weep capability at the bottom of the balcony.

The balconies pitch heavily to one side. It may just be that we're seeing the other side in the photo with the stucco.

 

[KootK]

Or the drainage is getting routed here.

 

[JoshPlumSE]

Little Inch -

Thanks for the link to that previous thread.... For those of us who don't deal with this issue often, it's helpful to have links like that in this thread.

 

[oldestguy]

How's come every shot on the sides shows that line between two 4 x 4's, in the exact middle, full length. Not a natural split on every one. No joke. Makes the job look even more questionable.

 

[azcats]

Here are some zoomed shots from my original photos.

 

[KootK]

 

[BAretired]

Not much doubt about azcat's shot.

BA

 

[KootK]

Based on what we've seen so far, I feel that this looks like an uncommonly well detailed and constructed building of this sort. Ever since that damn SF balcony incident, we all seem to get frothy at the mouth every time that we see any balcony that's not an extension of a concrete slab.

I've been involved in a few wood/cfm projects where precast balconies were substituted for durability and that institutional feel. Anybody who's had a look a the fragile connections back to the stud walls in those setups is likely to feel safer on cantilevered wood, even with the rot potential.

 

[hokie66]

The member should have been rejected, rather than incorporating it in the structure. A better choice would have been a galvanized steel beam.

 

[r13]

The split beam is inviting troubles down the road. The stress flow of 2 - 4x4 wouldn't be exactly like 1 - 4x8, which was the base in design.

 

[KootK]

Don't shoot the messenger. Obviously, a full width, mid depth crack over a prolonged length has to have implications for horizontal shear transfer. It's pretty rare for that actually to be the case however.

 

[r13]

Wow! Glad that I am not a wood guy.

 

[KootK]

Meh, every material's got its issues.

Steel / CFM: buckling, buckling everywhere.

Concrete / Masonry: can't really ever figure out your loads or deflections with any certainty & minor detailing errors are catastrophic.

Wood: Tension perpendicular to grain and checking.

I'm holding my breath for structures built from monolithically site cast, 36 ksi steel rectangular sections.

 

[Tomfh]

Yeah checks are common in wood. I wouldn’t pretend to know the acceptable limits.

Not sure anyone in this forum does from the sounds of it!

 

[Celt83]

This document is a little older but searching checks gives some good breakdowns on the impact. American Wood Council (PDF)

Repeated row houses like this are typically done as cheap as possible in some instances that means if its a big developer like Pulte, etc. pay a little up front premium to get some performance based design to side step some code criteria and satisfy the AHJ (Authority Having Jurisdiction) if it will net them material and labor savings. Part of the penny pinching is also the grade of lumber I wouldn't be surprised if they were using stud or standard grade lumber which would explain the checks and some of what looks like twist also.



My Personal Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

Open Source Structural GitHub Group:

https://github.com/open-struct-engineer

 

[Celt83]

Nice Illustrated Guide on Grading: Link
One more PDF: Link

My Personal Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

Open Source Structural GitHub Group:

https://github.com/open-struct-engineer

 

[r13]

Which one below is better description of the defect in the OP's photo?

 

[dauwerda]

I don't even see a check in the picture on the left that you posted, r13.

But, based on this picture below the wood is checked, not split, as the crack does not go all the way through the timber, it terminates at the center of the timber (probably the center of the tree) and does not go all the way through.

Here is a decent blog post on the subject of splits/checks

http://www.woodscienceconsulting.com/wood-science-consulting-blog-/2015/7/30/checks-and-splits

 

[r13]

The photo was taken from the referenced material, it gets me too, so posted for comment. The definition below each seems good though. The earlier reference material referred to several ASTM documents, which may contain grading guidelines and acceptance criteria.