Solar PV Structural

I'm not sure of your point of view or where you are. It would be helpful to other members if you posted full names instead of just initials, members who are not sure have to web search the acronym only to find out that they have no interest in the thread.

MWFRS = Main Wind Force Resisting System

C&C = Components and cladding.

20sf is C&C

If you are in the USA, you need ASCE7, ASCE7-10 is just being released. There is a scale of multipliers depending on the square footage of the component.

From a structural engineering point of view, a wind tunnel test would be a waste.

http://www.asce.org/

ok thanks - i'll keep that in mind in the future - actually i am in NY, so we usually have 110 mph or 120 mph wind. our adopted code is the 06 International Building Code, so we design in accordance with asce 7-02, but will accept designs from other professional engineers where design is delegated if in conformance of asce 7-05. i wonder if anyone knows if the asce7-10 or 2009 ibc will have further direction on best practices for applying provisions to these types of structures- anyone researched it yet? thanks for responding in advance!

oh yeah, why do you think wind tunnel is a waste? just like to hear your thoughts. thanks.

Re: wind tunnel. The total design loading on the structure is so large that a very large percentage over or under estimate of the contribution of the PV would be a very small percentage of the total loading. Using the ASCE component loads shouldn't be far off.

If I manufactured the panels, I might feel differently.

GA Pass...,

I have found this subject to be very frustrating, My engineer used ASCE tables for a new PV rack design to calculate wind loads which already have a saftey factor that is doubled, then he takes this number and multiplies it by 3 for his saftey factor, it becomes rediculus. What is needed is some finite element analysis to reduce the redudent saftey factors because all the extra material and its weight are adding significantly to the cost of PV installations.

Spacecannon

Is it possible to get a system that will in very high winds turn the panels so that they represent minimal wind resistance.

You could use a wind speed indicator linked to the solar trackers.

I prefer the system of solar panels mounted on roundabout style mounts.

They are low to the ground but I understand you may not have this option due to shading.

Yes many large single pylon racks are set up to turn horizontal in high winds.

And they would complicate everything along with bringing significant additional costs.

Yep,

Thats why I only use thin-film fixed ground-mount systems, he asked...

Spacecannon

You should just follow the manufactures recommendations the assembled system can handle.

They normally say a figure about how much wind speed they can handle and I am sure they have tested the systems in a wind tunnel or at least real world and have data.

published code requirements for the calculation of wind loads on photovoltaic panels is probably a bit too much for people who publish codes.