Splicing a bearing post
Perhaps one of you engineers will see this, or someone else here has encountered this situation:
I am wondering if it is structurally OK to splice a 6X6 post on a deck railing corner in order to make it taller to go up and support a girder that will in turn support a truss roof over the deck.
I was thinking steel plates on adjacent sides, then a plywood skin bridging the splice, then wire and stucco.
Going with a new post from the pier to the girder would entail a partial demo of the deck. The pier has been deemed by the AHJ as being suitable to carry the loads of a new roof.
The AHJ will probably require an engineer’s sign-off on any splice, I just thought I would see what the brain trust at BT had to say.
This project is still in the estimating phase.
Offhand it sounds like a bad idea to me. Especially since it supports so much.
I wonder if a laminated post would work better? Splices could be staggered, and it would be easier to put up....
There are ways to do that with simpson nailer plates or straps for sure, but I doubt you will be able to develop the full strength of the 6x6 with nails; however, it is unlikely that you will need to develop its full capacity. If you have space for knee braces to the columns that would help. If the existing column extends above and below the existing it may be a pretty easy fix since the existing will be fairly rigid with foundation and floor support. I would compare how much it costs to replace the 6x6 vs the headache of getting an eng involved to design the alternate solution.
Thanks, Brad, that's what I am doing, trying to compare the costs of replacement vs getting an engineer.
The existing piers aren't large enough surface to simply add another post alongside the deck post, which would have been a fairly simple solution. It's either splice or replace with a new full-length post.
I presume the 6x6 extends below the deck floor and sits atop the pier so this post functions as a support and the rail. If you cut the post off flush to the top of the deck it is far easier to make this connection work. Splicing mid height is not the simpliest solution because most engineers will not consider the railing to be an effective brace as it can be removed and that would lead to a problem. Cutting at the top of the deck should elimate the need for an eng because the column can be properly supported by both the deck and the new structure at the top.
Interesting thought about cutting the post at the deck surface. You are correct that the posts extends below the deck to the pier and is currently the corner post for the deck railing.
I will talk to the BI about this approach.