NDS help (im confused) with simple post and beam bolts 3

[eaglesal]

Sorry in advance, this is remedial stuff:

I'm trying to size bolts for a porch. 8" round posts are 10' on center and resting on top of that post is a 4"X12" beam notched into the top.

The notch is cut out of the top of the post as to create a saddle condition for the beam to sit in. Top of beam and post are flush.

THis is now a double shear condition/connection?


My main concern for this condition is uplift. I have 2500 pounds of uplift per post. Using the NDS for Southern Yellow Pine, I'm getting a requirement of two 3/4" bolts when looking at Z parallel (1330 each bolt for the side member)

Can someone help me understand my loading conditions with repsect to parallel and perp to grain? When using chart 11F do I just got with the lowest Z value and design for that?

My initial thought is that both beam and post would be loaded perpindicular to grain under uplift forces.


thanks in advance.

 

[LowLax]

It sounds like the beams are lifting up away from the top of the column. The configuration sounds like the beams are the main member, and the notched post makes up the side members. So you would have 2" side members and a 4" main member. Looking at table 11F NDS '05, I'd pick the 3.5" main and 1.75" side member and then use the Z perpendicular with the little "m" by it since your main member is loaded perpendicular to the grain. Using G=0.55 I'd get 1550lbs for a 3/4" bolt.

I assume the grain of the post runs vertical and the grain of the beam runs horizontal.

 

[akastud]

eaglesal,

The uplift load causes parallel to grain in the column anf perp to grain in the beam.

akastud

 

[eaglesal]

THANKS for your answers. Using Z main perp. makes sense.
The Z parallel numbers, is that using both members in parallel loading which I dont have?


So using Z main perp I get 1550 per 3/4" bolt. What if my Z side perp was less than that number? (they are both 1550) Would I design with that?

thanks again.

 

[Ron]

As akastud said, parallel in column and perp. in beam....so check both. It is a double shear connection if thru-bolted.

 

[JAE]

gasp.

Ron...

where have you been lately?

 

[Ron]

Hi JAE...sorry for the hiatus...just been busy. Business is pretty good. Lots of failures to look at!!

Hope you're doing well.

I'll send you an email and fill you in.

 

[msquared48]

Is there something you guys need to tell us????

Mike McCann
MMC Engineering