Guardrail Structural Analysis

[Joe_Carrick]

I've been doing calcs for wood guardrails (the rails and the posts) for decades.  It seems to me that this is such a common thing that there must be software available to do the calcs.  However, after extensive searches on the web I haven found anything at all.

 

Does anyone know of such a program?

[DRAWZILLA]

funny, I've been doing railings for a lot of years, and having them engineered, the only thing that may change is the bolt spacing for the posts, and post spacing, that's it.

[Joe_Carrick]

41 minutes ago, DRAWZILLA said:

funny, I've been doing railings for a lot of years, and having them engineered, the only thing that may change is the bolt spacing for the posts, and post spacing, that's it.

Basically, that's true but there are a lot of new products available (Simpson Timber Screws for example) and changing thoughts on how the connections effect the twisting of joists, etc.

I think I'm going to just start using the Simpson Technical Bulletin

• Guard Post Installation Using Strong-Drive SDWSTIMBER Screws

It's only for the post being 36" above the deck - but the design load at that point is 500 lbs, well above the CRC required 200 lb point load. 

• 500x3 = 1500 ft.lbs.
• 200x3.5 = 700 ft.lbs.

I'm finding that many Building Departments are not only accepting but actually requiring this sort of documentation in ConDocs.

 

The one thing that's really interesting is that in most cases they are not checking the guardrail itself - just the posts. 

 

I provide calcs for the guardrail as a beam with a 200 lb load at mid-span (vertically and laterally).

[dshall]

Often times the type of handrail changes.  I do a boiler plate detail to get past the plans reviewer.  Another one of those annoying tasks.

[Greg_NY61]

The railing should be sturdy and not wobble. The way they do 200LB test on the railing to make sure it's load compliant is they put railing under 200LB  pressure and they release the load 24HR later and the railing should return to its original position with 1/4" leeway.

 

If you want to do a quick test on the railing I use Pocket Penetrometer. 

[DRAWZILLA]

My son went through the ICC approval process with his Glass railing system they sell. they have their own in house engineers and he said it still cost the company a $100,000 to do it. That's why you don't see everyone getting those approvals for railing. Their glass railing is the only ICC approval I have seen yet.

[Richard_Morrison]

On 4/28/2018 at 2:41 PM, Joe_Carrick said:

The one thing that's really interesting is that in most cases they are not checking the guardrail itself - just the posts. 

 

I provide calcs for the guardrail as a beam with a 200 lb load at mid-span (vertically and laterally).

Probably because with posts 5' or so apart, even a 2x4 flat railing with intermediate balusters is going to calc out easily as a guard.