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I have a customer who wants to replace a sign.They want a 4' x 8' and a 2' x 8' mounted between two posts. The bottom of the sign will be 5' above the ground. which will put the top of the 4'x8' panel 11'6" above the ground, assuming a 6" space between the two signs. Will pressure treated 4"x4" wooden posts be strong enough or should I counsider using mild steel square tubing?...
Thanks in advance
------------------ Mark Perkins Performance Signs & Graphics Eunice, Louisiana "The heart of Cajun Country"
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Mark.. For a 4x8 and a 2x8, without going into windloads etc., I would think that 2 6x6's would be more than adequete.
------------------ Dave Grundy shop#340 AKA "applicator" on mIRC "stickin' sticky stuff to valuable vessels and vehicles!" in Granton, Ontario, Canada 1-519-225-2634 dave.grundy@quadro.net www.quadro.net/~shirley "A PROUD $ supporter of the website"
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Dave, I was planning on using 6" x 6"'s but I can't find a lumber yard in my area that carries them in anything longer than 10'. I plan on going 4' into the ground so I'll need a 16' post. I can get 4" x 4"'s in that length but I'm scared they will not be strong enough.
------------------ Mark Perkins Performance Signs & Graphics Eunice, Louisiana "The heart of Cajun Country"
I just looked in what most sign folks consider the bible of sign engineering, "Signs, Structures and Foundations" by Peter Horsley.
From his formulas and my outhouse engineering, here's what it looks like. Basicly you have 48 sq. ft. of sign area, and the center of the heigth of the wind loaded area is 8'-3" above grade. Unless you are in the hurricane area of Lousiana, anything under 17'in heigth, you should figure on 24 lbs, per sq. ft. OK, here the calculations.
48 sq. ft X 24 psf = 1152 lbs wind load.
1152 x 8.25 heigth = 9504 lbs bending moment. (thats the bending force at grade)
Half that since there's two posts = 4752 lbs. bending moment per post.
Now here's where a lot of variations come into play depending on what species of lumber you are using, but assuming it's probably southern white pine, which is one of the weaker species, Horsley's charts show a factor of .24 for figuring the size of the support.
4.752 kbm X .24 = a timber of 11.4 sq in section modulus. A finished 4x4 would be 3.5" square, or 12.25 sq in section modulus.
Translated to Cajun, that mean 4x4 probly gonna work, unless you live where de hurrycane come, den you betta use 4x6 and hope for de best.
------------------ Jerry Mathel Jerry Mathel Signs Grants Pass, Oregon signs@grantspass.com
[This message has been edited by jmathel (edited September 19, 2000).]
[This message has been edited by jmathel (edited September 19, 2000).]
Posts: 916 | From: Grants Pass, OR USA | Registered: Dec 1998
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Hey Jerry, You sound more cajun than me, and I've been here all my life LOL I'm about 100 miles north of the gulf so usually the winds have died down to a tolerable level by the time we get the storm...the other sign shop in town has bid on this sign using 4x4's they have been in business 30 yrs...but they do have a lot of leaning signs......hmmmmm...but den if de wind blows thad bad I can blame the failure of the posts on a flying pirouge out de bayouuuuuuuu. Thanks a bunch
------------------ Mark Perkins Performance Signs & Graphics Eunice, Louisiana "The heart of Cajun Country"
If looks have anything to do with your sign, use posts that are 6x6. 4x4's are going to make the over all job look like a postage stamp on tooth picks when viewed from a distance. "Cheap and weak" is the impression you'll be sending even though 4x4s are strong enough.
------------------ Go Get 'Em..... :) AKA Raptorman on #Letterheads mIRC Chat Draper The Signmaker Bloomington Illinois USA
Proud 2-yr. $upporter of this Web Site (May 1999-May 2001)
Posts: 2883 | From: Bloomington Illinois USA | Registered: Nov 1998
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My grandma was from that country. I grew up listening to her talk pure "coon-ass". I guess some if must have rubbed off on me. Hell, I must have been about 12-years-old before I found out my first name wasn't "Jerry Ben", and I still like to eat "ditch lobsters".
------------------ Jerry Mathel Jerry Mathel Signs Grants Pass, Oregon signs@grantspass.com
Posts: 916 | From: Grants Pass, OR USA | Registered: Dec 1998
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Mark, Use two 4x4's each side (back to back) with a 2x4 (or 2x6) over the butt to dress 'em off. You'll find that a 4x4 that long even if it holds the wind load is gonna warp like crazy. By using this method you'll add a lot of stability and looks. Put them together with galvanized deck screws and she'll be there for the long haul.
------------------ Larry
Elliott Design McLemoresville, Tn.
If you can't find the time to do it right, where gonna find the time to do it over?
Posts: 486 | From: McLemoresville, TN. USA | Registered: Nov 1998
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I would prefer steel tubing myself. This way theres no question, Steel tubing isnt that much more expensive either. We used 4"x6" steel on this one, but it is a 10'x8'. I just sleep better at night knowing we used steel.
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6"x6" PT would be the best, here in Naples they would make you use 4-6"x6" post, 4' deep hole, 24" in diameter with concrete, but this is hurricane country. How about 3-4 4"x4" post or steel would be bullet proof. Talk to the customer, If he's on a budget, taking bids maybe he doesn't want to spend the extra money. But if he's looking for a lasting installation go with the heavy duty install. Here we don't have to worry about such things as the county makes us get an engineering drawing and he specifies all of the materials etc. on anything over 32 sq. ft. or taller than 9'
------------------ Robert Thomas Creative Signs In Beautiful Naples, Fl.
Posts: 965 | From: Bonita Springs, Florida USA | Registered: Feb 2000
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I often prefer steel tubing for installs like this. Eighth-inch wall by three- or four-inch square tube. For shorter signs, even 14 ga. wall thickness. No warping, no splitting, nothing. I get it in 20' lengths, and it's easy to cut with a cheap cut-off saw, easy to drill (and tap) and easy to weld with the small wire welders.
Also, there are tons of different decorative items that can be used with steel posts. Cast-iron finials are made that fit over one-, two-, three-, and four-inch square tube. I used to put set screws in the finials, as I've had problems welding cast-iron to steel. Now, I just glue them on top. Also, there are decorative metal rosettes of different sizes that can be rivited to the post, and cast-iron brackets of all different sizes and designs. Fabrication is easy, and painted with a metallic gold, brass or copper colored acrylic enamel, steel can look very dressy.
I also find that an installation like the one pictured by the Brad above is quicker for me to fab out of steel than wood.
Brad
[This message has been edited by Brad Ferguson (edited September 22, 2000).]
[This message has been edited by Brad Ferguson (edited September 22, 2000).]
Posts: 1230 | From: Kansas City, MO, USA | Registered: Nov 1998
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Jerry, That book sounds interesting but I could not find any info on it. Searched the web on dogpile, Amazon etc. Where did you find it, or more importantly where would I find it? Thanks
Roy
------------------ Roy H. Somers Sunflower Graphics 609-601-9700
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Hi.....just this past week I made 4) 4'x6' signs in which 3 of them go together like a C and one of them stands alone. Well the attorney, architect and realtor all insisted on having 16 foot posts. (they wanted the signs to go above the temporary cyclone fence) I asked them how deep the posts would be dug in. And mentioned that I thought the signs would look sort of funny sticking up that high in the air, and if they weren't dug deep enough....would either blow over or start to lean. Well.........guess what...at 5:00 yesterday, they were all frantically calling to see if I could deliver shorter posts. They said the signs looked funny 'up that high'. DUH
------------------ "surf" or "MoJo54" on mirc Cheryl J Nordby Signs by Cheryl (206) 300-0153 Seattle WA....!
Make your own glitter. Then follow your own shine. Linda Knight
[This message has been edited by cheryl nordby (edited September 23, 2000).]
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