Spanning 14’ catwalk timber size

[Schweg2]

Hi folks, I’m wanting to build a 3’ wide catwalk 14’ long from a loft to a gable. I was looking for input on sizing some Timbers that would span that distance. My plan was to mill a couple oak logs and have them exposed to the interior. Ideally I’d like to use 8x8 but guessing that would be undersized. 
What’s your thoughts?

[Jim_Rogers]

Maybe DonP will be able to tell us what floor load rating should be used for a catwalk. I don't know.

Jim Rogers

[beenthere]

Is the catwalk just to walk on? And under the roof? 

Depth of your support joists more important than width. And yield to DonP. 

[Schweg2]

Yes the catwalk will be in the interior, I want to have a door on the gable end the catwalk will lead to. This will limit my depth as I will already need to get a custom shortened door. 

[Don P]

I think I'd bump it up to 300 pounds per lineal foot on the catwalk or 150 plf on each beam, they tend to attract a crowd on occasion. That said, strength is my concern, I'd let deflection go a bit.

Go here;
Design for Bending (forestryforum.com)
Load is 150lbs/' x 14' = 2100 lbs
DL=420#
8x8 #2 mixed oak P&T
I'm getting a pass and within floor deflection limits, woohoo, hit the easy button.

[Schweg2]

Thank you Don! 
With that being said what size header would I need to support the 8x8’s on the gable. It’s post framing and the posts are 8’ apart. 

[Don P]

Assuming these are landing in the worst location, centered between posts?

[Schweg2]

That is correct Don…centered between the 8’ posts. 

[Don P]

It's slightly better than this but in keeping it simple, we have a center point load calc. I am using mixed oak numbers, if you are using one of the better oaks that can improve things.

Half of the catwalk is bearing on the header, so 7' and we said 300 lbs per foot so again a 2100 lb center point load on the header, go here;

Midspan Point Loaded Simple Beam (forestryforum.com)
Load is 2100, span 96, 8x8 in #2 mixed oak P&T so
Fb 575
E .8
Fv 155

That does pass... if that is the only load on the header.



 


 

I welded steel posts up and structural screwed them to the beams and then wrapped that and sourced full length kd oak railing material, I still have the backups in the barn, it was over in Bristol so I bought enough to screw up once. I think it started as 20' stock. My vision/nightmare is, the entire wedding party leaning on the railing for pics.


 

[Schweg2]

Very nice! Thank you sir for the help.