I have to remove a brick column and rebuild. I want to support the porch roof (just a roof no live load) with 2x material attached to a stake maybe 6' back from the porch. the porch roof is about 10' above grade so the bracing would be greater than 45*, closer to 60*. Just wondering how deep the stake would need to be to not move (clay and loam type soil, not sandy). I'm thinking 2'-3' should be enough. Also what size braces I'd need. I'm thinking 2- 2x10-16's but wondering if 2x12's are warranted
temporarily supporting porch roof
dom-mas
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https://courses.cit.cornell.edu/arch264/calculators/example7.1/index.html
Only thing stronger than a T shape is a square maybe some 4x4's. it all comes doen to how the brace is pinned to the ground. for under 100 bucks you can get a pretty strong metal shape 20' long,, metal does better with bending. don't know if you have already done the work but I can do some BASIC structural calcs for you. what are the dimensions of the overhang covering the porch,, what is the distance to the next column or bearing point
Only thing stronger than a T shape is a square maybe some 4x4's. it all comes doen to how the brace is pinned to the ground. for under 100 bucks you can get a pretty strong metal shape 20' long,, metal does better with bending. don't know if you have already done the work but I can do some BASIC structural calcs for you. what are the dimensions of the overhang covering the porch,, what is the distance to the next column or bearing point
Well i didn't use any of those approaches. The ground is so thick with roots that I couldn't get a stake more than about 6" deep an I tried in quite a few spots. Worst digging ever, did more work with the sawzall and a pruning blade cutting roots than with a shovel.
ended up supporting the deck and putting a post up on either side of the column, bearing on a plate to spread the weigh. it's not ideal because it leaves me less room to work but any beam I made to go across the corner would have to be 14' to avoid the stair and the hole we dug. Anyway, it's solid
ended up supporting the deck and putting a post up on either side of the column, bearing on a plate to spread the weigh. it's not ideal because it leaves me less room to work but any beam I made to go across the corner would have to be 14' to avoid the stair and the hole we dug. Anyway, it's solid
Yeah, Dom-mas, I was going to say that I've done quite a few of the temporary t-posts, or doubled 2x's, bearing directly on some type of 2x cribbing sitting on top of a larger piece of 3/4" plywood, if (and I do emphasis the word "if") there isn't much of a load. In fact, on light enough loads, I've even done this on just a piece of 3/4 plywood large enough to evenly distribute the load.
Then again, the entire shoring you're proposing (or anytime any of us do this) depends entirely on the loads imposed on the column (posts), the length of the columns, even the species of wood used for the columns.
In reality, the ultimate stresses that would actually cause failure in the column is variable due not only to live/dead loads placed on it, but also due to defects, size and location of knots, lumber density, and even moisture content. If you're interested, there is a formula we can use to insure a safety factor to let us know that the loads placed on any column/post will result in it buckling so badly it could fail under those specific conditions. I usually will implement the calculation of all this if I am questioning the situation at all. It helps me to better design my posts, or spacing, footers, etc, in order to prevent a disaster. But suffice it to say (and as already mentioned) that the t-post will resist buckling more so that if the same two pieces of dimensional lumber were tied together with the grain running parallel.
Then again, the entire shoring you're proposing (or anytime any of us do this) depends entirely on the loads imposed on the column (posts), the length of the columns, even the species of wood used for the columns.
In reality, the ultimate stresses that would actually cause failure in the column is variable due not only to live/dead loads placed on it, but also due to defects, size and location of knots, lumber density, and even moisture content. If you're interested, there is a formula we can use to insure a safety factor to let us know that the loads placed on any column/post will result in it buckling so badly it could fail under those specific conditions. I usually will implement the calculation of all this if I am questioning the situation at all. It helps me to better design my posts, or spacing, footers, etc, in order to prevent a disaster. But suffice it to say (and as already mentioned) that the t-post will resist buckling more so that if the same two pieces of dimensional lumber were tied together with the grain running parallel.
I'm still just confused as to why the grain is running in a different direction if it is in a T rather than doubled up. The grain is still running vertically. Only 2 directions for grain right?
And for this sort of stuff i prefer to just overbuild. There is virtually zero weight anyhow. The porch is maybe 24' long with a post @ the far corner , then another at the steps that are about 4' wide then the post I'm working on. Most of that roof is cantilevered from those 2 remaining posts. The column came down so easily that there was no way any serious weight was on it.
By the way. how common are hollow wood columns in other areas? Around here hollow 8x8-12x12 columns made of 1x material are the usual in the older neighbourhoods.
And for this sort of stuff i prefer to just overbuild. There is virtually zero weight anyhow. The porch is maybe 24' long with a post @ the far corner , then another at the steps that are about 4' wide then the post I'm working on. Most of that roof is cantilevered from those 2 remaining posts. The column came down so easily that there was no way any serious weight was on it.
By the way. how common are hollow wood columns in other areas? Around here hollow 8x8-12x12 columns made of 1x material are the usual in the older neighbourhoods.
Posts rarely fail in compression unless they are very short. Most often a post will fail in buckling. That is why the carrying capacity of a post/column is always based upon its L/r ratio, or "slenderness" ratio. In other words, the post will buckle in its thinnest (slenderest) dimension (which is what it must be designed for). The t-post will simply increase the slenderest dimension (provided it is sufficiently tied together with proper type and placement of fasteners to resist shearing).
I know a 1/2 inch sounds insignificant, but it can mean a lot when considering buckling of a post (also depending on some of the other factors I mentioned earlier). Kind of like what you were talking about when "overbuilding" something. I tend to err on the side of overkill myself. If I can make a post stiffer, even by a little bit, I typically do. Under small loads, buckling really doesn't come into play, especially if one simply exercises good common sense when placing the temp shoring.
Sounds like you've got a good handle on everything, Dom-mas!:thumbsup:
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What the heck is a 2x4 T?
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