Recently I've been designing commercial electrical signs. Signs of the type that are on tall poles, or the big pylons and monuments you see in shopping centers, roadsides, etc. lit by neon and/or fluorescent lighting.

In order to properly choose the size of poles, and the depth and diameters of concrete footings for these poles, I use various reference charts such as Section Modulus Charts and Caisson Footing Charts (enter Height to Center of Sign, and Square Foot Area of Sign to get the required Section Modulus, Required Footing Size, proper anchor rod sizes, etc).

The problem is that all the charts I can find only go up to 300 square feet and 75 feet in height. Beyond that, I have to extrapolate. As we are beginning to build signs that are 1000 square feet or more, I'd rather not rely on my ability to extrapolate in order to make pole and foundation recommendations. I am not the final authority on the specs that I suggest, but initial designs do come from me and I'd prefer them to be as accurate as possible, of course.

Does anyone know where I can access charts that go beyond the limits that I've stated?

I'm in the SW United States but we build signs all over the western half of the country.

Thanks!