Canada design windspeed map

[greencircle]

I am looking for a map of Canada showing design windspeed map for use with structural designs of signs and light post.
Can any body point me to a good resource. My google search did not result anything useful.

 

[jayrod12]

the NBCC and it's stuctural commentaries will have everything you need.

 

[greencircle]

Thanks

 

[TLHS]

To clarify, though, we don't provide straight up wind speeds in the Canadian codes. There are design pressures that then get modified for various situations.

Those can certainly be translated into windspeeds, but you have to do some screwing around to get something comparable to the ASCE values from a couple of years ago. I don't remember what it is off the top of my head, but I think it's the duration of the reference event that's different. It's not quite plug and play. Then, on top of that, the design pressures definitely aren't compatible with anything expecting the current ASCE wind methodology.

If you're thinking you can just plug a windspeed into a US code or design formula and get the same level of safety, you could end up in trouble. You'll either need to get to a final pressure using the Canadian methods and load factors, or spend some time reading about how both the US and Canadian numbers are derived and translating between them.

 

[allgoodnamestaken]

I highly recommend you get your hands on a copy of the structural commentaries on part 4 division B for the process of figuring out wind loads for the NBCC.

 

[greencircle]

I wish it was a bit easier. something like [URL unfurl="true"]http://windspeed.atcouncil.org/[/url].
Anyways, I guess I may have to buy a copy. I want to be able to publish a wind map on out company website. Not sure if I will have to get their written permission.

 

[allgoodnamestaken]

If you just want the non-design wind pressures, those are in the National Building Code of Canada in tables. But the process of taking those values and creating design wind load values is dependent on a lot of other factors that are site and design specific, and those are clarified in the structural commentaries.

I don't know anything about the legality of taking the wind tables from the NBCC and creating an interactive map out of them. You'd have to talk to an intellectual rights lawyer about that.

 

[TLHS]

What are you going to use the map for, though? By itself it doesn't mean anything.

 

[greencircle]

we manufacture structural support poles for banner/flags & signs. I am planning to show Canada map and US map on our pole brochure for customers to refer to when choosing our products.

 

[TLHS]

The Canadian values aren't compatible with US numbers though. So if you're rating a pole to a 100mph windspeed as per ASCE-7, you can't look at the Canadian code values and have any idea how that corresponds without doing a code comparison and some math.

Putting a table on your website that says the 'Code Design Hourly Wind Pressure' for somewhere is 0.57kPa could be even worse, because you might get a person that doesn't know any better taking that number and multiplying it by the sign area, then designing for that. In reality, the actual design number could be 4+ times that value for a sign after using various co-efficients.

If you're going to develop ratings for your poles based on Canadian values as well, then that's great. But then you're going to need a Canadian engineer and a copy of the code at a minimum. If you're not, then just don't provide the Canadian values and let Canadian engineers work out the appropriate rating to buy to meet local code requirements.

 

[greencircle]

Good point. Sounds like I have more work on my hand. Thanks for your opinion.

 

[medeek]

A while back I was trying to come up with an interactive map for Canada as well but I basically ran into the same problems as described above. With the ASCE I was able to obtain permission to post an online snow load map. The ASCE is actually pretty good about this sort of thing, you pay a small one time fee and they grant you rights to specific maps or images that you requested.

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com

 

[geoffdale]

Check out

http://www.jabacus.com

It has the climactic data and load calculations there for Canada.