narelmr alum pole

What do you mean by bending strength, what are the dimensions of the pipe, and how is the pipe supported and loaded?

4'' diameter used for a pylon sign under 90 mph (18psf) wind load- 4' high x 3.5' wide

bottom of sign 7' above grade

According to my AASHTO design tables there is no 48' by 42" standard sign. However; both a 48" by 48" and a 48" by 36" sign require a 4" diameter by 1/4" wall thickness aluminum pole with a 2' wide by 4' deep concrete foundation. A sign of this type also requires a break away connection at ground level.

there are signs of all sizes. just depends on what customer wants to pay. so, this sign is 48'' high by 42'' wide and is 7' off the ground. the footer is an augered type and is 2' in diameter

Nonetheless; for 90 mile per hour wind load, what I stated before is what the American Association of State Highway and Transportation Officials sign design tables recommends.