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I'm doing an estimate for a lighted sign. The proposal is for 8' high x 6'wide =48 sqft. It will be a 10'' single faced extruded cabinet with a single panface on the top half and three divider bars with 3 flat acrylic faces on the bottom half for removable tennant signs.
The single pole would be 6'' and the sign will be 10' off the ground. According to my calculations(which may be wrong) the windload @ 110mph would be 26lbs per square foot or 1248lbs with the face center being 14 off the ground. Also according to calculations this would require 2.4 yards of concrete and the hole would need to be 4'deepx4.1'x4.1'wide. So. I'll need a backhoe, crane,and portable welder. Should the hole be deeper?
Are the windload and concrete calculations correct? Will a 6'' pole be large enough? Will just pouring the concrete around the pole set 4' in the ground be strong enough?
Is a price of $4925 installed plus tax, and $200 to pull the permit about right? Also the client will be running the wires and connecting the power.
Any ideas or warnings appreciated.
[ May 26, 2005, 03:48 PM: Message edited by: Wayne Webb ]
-------------------- Wayne Webb Webb Signworks Chipley, FL 850.638.9329 wayne@webbsignworks.com Posts: 7404 | From: Chipley,Florida,United States | Registered: Oct 1999
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Wayne...This is just my humble suggestion, but if you have never done something like this before, you might be best to sub out the actual installation to a company that is experienced in the field.
You can still make a bunch of money on supplying the can and lettered faces.
I know that Grandpa Dan thrives on doing things that push the envelope, but in this situation I know I would feel much more comfortable having someone more experienced shoulder the potential problems that could arise down the road.
-------------------- Dave Grundy retired in Chelem,Yucatan,Mexico/Hensall,Ontario,Canada 1-519-262-3651 Canada 011-52-1-999-102-2923 Mexico cell 1-226-785-8957 Canada/Mexico home
Get yourself a copy of the book called "Sign Foundations" by Peter Horsely. It explains the calculating of wind load and the different types of loads.
I use mine quite a bit and it is extremely useful.
-------------------- Bruce Bowers
DrCAS Custom Lettering and Design Saint Cloud, Minnesota
"Things work out best for the people who make the best of the way things work out." - Art Linkletter Posts: 6451 | From: Saint Cloud, Minnesota | Registered: Jun 1999
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I guess it boils do to if you trust your arithmetic or not...
-------------------- Bruce Bowers
DrCAS Custom Lettering and Design Saint Cloud, Minnesota
"Things work out best for the people who make the best of the way things work out." - Art Linkletter Posts: 6451 | From: Saint Cloud, Minnesota | Registered: Jun 1999
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As you know we build a lot of unusual structures. Even so I never do up engineered plans myself - there's professionals who do that and they have gone to school for a bunch of years for the right. They also pay monstrous liability insurance premiums for the privilege.
The cost of the engineering is the customer's responsibility.
Generally I have a pretty good idea how something needs to be fabricated (better than most engineers I talk with)... and generally I err on the heavy side. Even so, for anything critical I engage an engineer to review and stamp my drawings or produce their own based on my scribbles. In the process he/she will size my steel and footings/foundations to what's needed.
Up in our neck of the woods we get what's called B1 and a B2 inspection forms for the authorities. As I understand it the B1's certify the drawings and the B2's certify that we built it accorndingly with inspections by the engineer.
It absolves our company from the liability and also lets me sleep at night.
It works for me and I wouldn't have it any other way.
-grampa dan
[ May 26, 2005, 06:59 PM: Message edited by: Dan Sawatzky ]
-------------------- Dan Sawatzky Imagination Corporation Yarrow, British Columbia dan@imaginationcorporation.com http://www.imaginationcorporation.com
Being a grampa is one of the the most wonderful things in the world!!! Posts: 8738 | From: Yarrow, B.C. Canada | Registered: Nov 1998
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You've helped me before Wayne so I ran the calculations for you. The Horsley book runs all their calculations at a maximum wind speed of 100 mph, so if your code in Florida specifies 110 mph because of hurricanes, these figures will be a little low.
At 100 mph windload and your sign size and height, I get 2 yards of concrete. Here in the north we have to figure 4.5 feet deep because of frost. I usually go over a bit so in my area I would go 5' down and 4' x 4' square for 2.96 yards concrete, and I'd feel safer for an extra $70 in concrete.
The required section modulus for the steel pole at 100mph windload is 7.68. With a single pole you won't have to worry as much about the customer adding more signs as can happen with 2 pole signs. They will string a banner or add a changeable message board later adding to the windload and making things unsafe. A 6x6 square pole at 1/4 inch thickness has a section modulus of 10.7. (nice overkill) A 6 inch round pole .28 thick has a section modulus of 8.48. (Nominal overkill for 100 mph windload.
So it looks like your calculations for 110 mph wind are pretty good, except for maybe the concrete, simply because the amount of concrete you figured is nominal for normal earth pressure. Loose soil would require more, and possibly a rectangular base.
I can't say on your price because I don't know what your cost on the sign is, but you can figure your cost of steel, concrete, about 2 hours to dig the hole, crane service to lift the pole, paint and painting time, (I use POR 15 with POR blackcoat, good stuff) When I set a pole that large I plan it for a Friday afternoon. My crane guy will leave the crane attached over the weekend while the concrete sets, and he only charges me a small extra fee for leaving it. You'll need the crane again for lifting the sign in place, and make sure your cabinet manufacturer builds the cabinet for your type of install. You'll have to go with vertical lamps and they will put a steel pole up the center with a flange at the bottom to bolt to your pole.
Good luck.
-------------------- Dave Sherby "Sandman" SherWood Sign & Graphic Design Crystal Falls, MI 49920 906-875-6201 sherwoodsign@sbcglobal.net Posts: 5397 | From: Crystal Falls, MI USA | Registered: Apr 1999
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Thanks Dan and Dave, Dave, Thanks for helping me with those calculations. The earth pressure shouldn't be a problem here bescause it's usually about 10'' of topsoil and red clay the rest of the way. That stuff is like concrete especially when it's dry. The frost line isn't a problem here like it is up north. But I'll allow for three yards instead and be on the safe side. I had forgotten you had told me about the POR 15. That would be the paint to use. Thanks for the crane info too. My crane operator is a good customer also and that probably wouldn't be a problem. Wayne
-------------------- Wayne Webb Webb Signworks Chipley, FL 850.638.9329 wayne@webbsignworks.com Posts: 7404 | From: Chipley,Florida,United States | Registered: Oct 1999
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As Dan pointed out , certified engineering drawings could be just one of the things you'll require along with a licensed installer.
What's required can differ in each city and if they "can't" understand how the calculations were made (or read them clearly) you'll have to get them to contact the engineer or convince them yourself, also different variences might apply and more than one permit could be required.
A local installer will fabricate the electrical sign and/or pull the required permit( having the requirments of each city they'vd worked in, on file and if they have to will get a temporary permit to work in other citys). I've pulled permits for this shop and know how long it can take sometimes. So when I give an estimate I note "permit costs not included". Dave gave good advice and I'm sure you can find wholesale fabricators for quotes to compare.
Hope this helps also.
-------------------- Joe McGillicuddy Signgraphix 2354 Lambert Drive, Pasadena CA jmcgillicuddy1@earthlink.net Posts: 20 | From: Pasadena, California | Registered: Oct 2003
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