Structural Ridge Splice

Question

Structural Ridge Splice

ReverenceEng (Structural)

(OP)

20 Dec 17 17:31

Have read a few different threads that I think are close to answering my question, but don't quite come to resolution.

Question is about splicing a wood ridge beam where a center support was removed by GC. Sketch attached for clarity/reference.

We have two 4x14 structural ridge beams that met at a post in the middle of the home. Each beam is about 11' long. Contractor removed the post and simply applied splice plates to each side with six bolts each end. This splice is at midspan.

If the beam were continuous, there is no way it can handle the load. Enercalc shows 250% over stress even with best case scenarios.

I don't think the calculation would work the same as if the beam were continuous so perhaps I don't have to worry about the previous statement (or do I?), but the splice must dump some moment into the end of the beam while resolving the T/C forces generated by the "overall moment at midpan"...looking for guidance.

1. I'd like to know if anyone can point me to somewhere, or give advice, on how this calc should be performed.
2. Does anyone have thoughts on whether this "looks good" or "sounds about right", or "no, definitely not right or safe!"?
3. Does this even make sense? If a continuous beam couldn't have held the load, should we be attempting this splice?

Side note: the ridge beam actually measures 3.5" x 12.75"...anyone have insight here? Weird size.

http://files.engineering.com/getfile.aspx?folder=560e925b-cc76-4177-9f90-8b

jayrod12 (Structural) · Answer 1 · 2017-12-20 17:35:00

Bad!

Even a properly constructed splice only makes the beam act as if it's continuous. Therefore 250% stress.

Upgrades are required, or replacing the support.

ReverenceEng (Structural) · Answer 2 · 2017-12-20 17:44:59

That's what I initially thought and told the customer, but still second guessed myself...

Perhaps we can get a few more people to weigh too?

msquared48 (Structural) · Answer 3 · 2017-12-20 21:36:27

Very bad.

I agree with jayrod here.

The 4X14 is too small to make that span work, even if there was a splice in place that would work.

Options...

1. New ridge beam,
2. add a transverse beam with a king post at the removed column location, or
3. reinstall post.

Mike McCann, PE, SE (WA)

ReverenceEng (Structural) · Answer 4 · 2017-12-21 00:57:30

RE: Structural Ridge Splice

ReverenceEng (Structural)

(OP)

21 Dec 17 00:57

Thanks for the confirmation Mike.

mjr6550 (Structural) · Answer 5 · 2017-12-21 04:05:30

I assume that this is a structural ridge based on the size. As in no ceiling joists or suitable collar ties. What had been supporting the post?

ReverenceEng (Structural) · Answer 6 · 2017-12-21 14:31:31

It is - no CJ or ties anywhere. There was a stud pack (from pictures) of about 5 2x4's where the two terminated at midspan.

tolchijb (Structural) · Answer 7 · 2018-01-04 21:30:04

I agree with your assessment if you are looking at this as a pure beam supporting rafters. If you look at the two sloped roofs as plywood beams spanning end to end and leaning on each other at the ridge beam then the splice may work since it is really acting as a tension member and not a true beam. For new construction I would never analyze it in such a manor, but when I am in 100 year old houses and barns that have been loaded in every combination over the years and are still standing, I think you owe it to the owner to explore all avenues. The stud pack may have originally been an erection aid that was not needed once complete and acting as a single designed unit. Just my thoughts.

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