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Is there a calculation for working out the wind load?
We are making a directory sign for a business park and we are arguing ovet the diameter of the pole, obviously if in doubt use the larger!!.
Anyway 7 panels 2800 mm x 340 mm horizontally mounted. First panel approx 610 mm from ground level, Top of pole approx 3400mm tall. 1600mm buried,
Is there a calculation for working out the wind load for pole diameter, weight of panels etc.
And how much pole do we bury in the ground in relation to the overall height?
The pole diameter we are looking at, at the moment, is 75/80mm and I think 125mm is the next size.
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9 Replies
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Tim…
can’t help with an exact calculation of the windload? 😕 bit too techy for me…but…
I was always told to bury one third of the post below ground leaving two-thirds above.
furthermore, a trick I’ve used over the years to strengthen posts was to take a large plastic funnel and, removing the post caps, fill the posts with fine sand. if you’ve ever tried to bend a pipe filled with something like sand you’ll appreciate it’s virtually impossible!
With posts filled in this way, damage from high winds or kids swingin on ’em is more likely to result in a gentle bending of the posts – not a catastrophic failure! – an important safety feature.
You can buy the sand in easy to carry bags from DIY sheds or builders yards.
hope it helps.
more soon
mikethesign
P.S. don’t forget – only pour sand into posts already set into the ground…otherwise it’ll all come straight out the bottom! 😛 [raspberry] 😉 😆 😆 😆
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Tim yes there is a formula for working this out but I dont know what it is, this is more in line with Dons expertise as there is a British Standard to cover this sort of thing. Robert fits a fair few of these post and panel signs so I expect he will know. As for pole sizes after 76mm is 89mm then 114mm so you do have larger poles before you reach 125mm. Ashby keep the full range in stock.
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Tim,
If you get a quote from Ashby Trade, they will advise as they have the calculation program. -
We are dealing with Klockber metal services, never thought to try Ashby.
Mike, like the sand tip, that should strenghen things up if short of space and time etc. I aslo have heard bury a 1/3rd which I think works out in most cases.
I am sure any of the metal suppliers can help, but I have always like to have a basic formula for calculating the costs of post and panels so I can givevery quick estimates.
With klockner I know thay charge APPROX £40-£45/ sqaure metre of 11g, so this lets me work out ROUGHLY the total cost of panels etc.
I think pole is about £5/metre, so again I can calculate a guide price without waiting for Klockner / Ashby etc to get back to me.
The reason for my original post was more out of interest than anything, just wondered if there was any kind of rule of thumb thing, going on.
Thanks anyway guys.
Tim
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Hi Guys
Yes there is a set formula for thi sort of thing which also tells you how big a hole to dig and how many cubic mtrs of concreate to fill it Etc.
ItRetails for about 195 sterling and I think its Don you need to speak to if not Then there was an a piece about in in the sign update mag about 3/4 issues ago You can browse back copys on line.Regards….FB
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I remember seeing something similar on http://www.letterheads.com, go there and have a look, or register and post the same request there.
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I have the formula at home. We post within 24 hours.
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Cheers Scant, looking forward to reading that.
maybe I will get to use some of the maths i learnt at school and never thought i would ever use again!
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My background is in electrical engineering, although having been Technical director, firstly of GEC Claudgen and then Oldham Signs, you do get to be a bit of a jack of all trades ( I won’t add the second part of this saying).
The head of my design office at Claudgen (now freelance) was John Russell who can be reached on 0208 845 4764. What he doesn’t know about wind pressures, sign structures and foundations isn’t worth knowing. He is doing calcualtions for sign companies all the time.
As far as standards are concerned, there are two:
BS 6399, Part 2 shows how calculations for wind pressure are carried out. This Standard is primarily designed for buildings but after much lobbying from the BSGA now contains sections that make it fairly useful for sign calculations. A guideline on how to use this Standard will shortly be completed for BSGA members.
I learned at a technical meeting last Wednesday of a new standard for the design of traffic signs (EN 12899, Part 1). I have not had a chance to look at it in detail yet but, since it covers (amongst other aspects) the structural design of free-standing signs – from small single-pole signs up to very large motorway signs – it should be apllicable for much of our work. As soon as I get my hands on a copy of this, I will let you know more.
In the meantime, John Russell is a good bet – his rates are reasonable too!
Best wishes
Don Dunthorne
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