Old Post and Beam?

[SteelPE]

I have a client who needs to do some work on an old post and beam structure. The client, a restoration contractor, is looking to removed and replace some beams that are 150+ (maybe even 200+) years old. These beams are sagging and have some shear cracks at their ends. The client is extremely confident that they will easily be able to replace a existing 7x7 chestnut beam with a new 9x9 oak beam. All beams are planned to be had cut onsite.

The client is looking to bolt a wood support bracket to the side of the existing columns and is asking us to calculate the capacity of the this new beam to column connection. the bracket is planned to be cut using oak (not sure if it will be red oak or white oak). My question pertains to the existing wood columns which are believed to be chestnut. Where can I find design values for this species of wood (without just running to google.... which has some information but I don't know how reliable it is)?

 

[RTF5199]

I did what you said not to and googled, but a cursory perusal suggests that Table 5-3a & 5-3b have some values for American Chestnut:

https://www.fpl.fs.usda.gov/documnts/fplgtr/fpl_gtr190.pdf

 

[lexpatrie]

I think the in-place specific gravity might be of interest as a kind of calibration. As to diagnosing a species of wood on site that has no grade stamps, that's a different question, and I think it's more of a Forest products laboratory sample of the wood kind of question, should that prove necessary.

Secondly what does the strength of the existing matter if it's being replaced? Are you intending to check the capacity and not concern yourself with the loads imposed? That's unwise.

Last, is the checking at the end the reason to replace the beams in the first place? I would look into this, as my understanding of the deeper beams and items like this is they have relatively low bending values as they "incorporate" a check or split in the element due to drying shrinkage.

Do please update as you acquire more information.

 

[SteelPE]

Well, if we need to change the end connection around then we will need to make sure the end connection works properly. The client would like to bolt a large block through the existing column with 4-1" dia bolts.... I need to make sure the bolts work, and come to terms with the eccentricity. Currently we are not in charge of the existing beam.

A full replacement of the beam is not possible as these beams are in the middle of a large frame..... and getting a tenon into the existing mortice is going to be impossible.....

For what it's worth.... the company doing the repair appears to be well specialized in this type of work. The person I met onsite has been doing this stuff for 35+ years. They just get questioned from building officials regarding the bolts into the existing columns which is where I come into play.

 

[Celt83]

The Old Carnegie Pocket Companions had strength values for wood to give you a starting place:
[URL unfurl="true"]https://www.aisc.org/publications/historic-shape-references/#28349[/url]

That References Trautwine's Pocket book which I believe is this one: Link