Ok, I re-checked my book. According to it a 125mph wind, at 10-14 feet above ground, exerts a force of 30 psf. So the "29 psf" I posted above wasn't off by much. But even going by the 40 psf figure I found on the net, I have plenty enough concrete. The formula LxWxCxP/2000xD indicates less than...
This is the book I found the formulas in. In it are 3 equations for figuring concrete with wind load as a factor. I will get the book out and review them for you when I get home. It also has a wind pressure formula. http://prodimage.images-bn.com/pimages/9780911380651_p0_v1_s192x300.jpg...
Yes, We are in a 125mph wind zone, and this is a formula I used...
W = width of face in feet
H = height of face in feet
C = distance in feet from grade to center of face
P= windload pressure (29psf@125mph)
D = depth of hole in feet
(W x H x C x P)/(2000 x D) =
(16x7x3.5x29)/(2000x2) =...
I used 9 gauge galvanized fence brace wire, strung it between opposite studs on the forms top and bottom, then twisted the wires tight and placed a small rod in the twist-holes to keep them from unravelling when the pressure was applied. As you can see I also staked the thing from about 3' out...
We made a trip to Marianna, yesterday evening, and picked up the block, rebar, and some of the form materials, The blocks will be stored inside the shop to keep them dry until time to lay them. This is to help prevent the mortar joints from cracking later because concrete blocks expand slightly...
This is another one I plan to build for my CNC enterprise. Except for the graphic elements made of HDU (high density urethane), it will made entirely from EPS (polystyrene), will be 96''x65''x18'', weigh less than 200 lbs, and won't need a foundation. I will cut it out on the foam cutter I...
I see what you mean. Thanks Big H. Straight sides they will be. I plan to pick up the blocks and form material this afternoon. The block will be stored inside until ready to use and I'll go ahead and make my forms. Then I plan to rent an excavator on Friday and hopefully we can get a concrete...
Yes, see my design in my second post, bottom left of the drawing. I plan to measure and stub up about 18" where the block cavities will be, lay all the block, place rebar down through the corresponding cavities and pour full of concrete. Yes, 4.5 yards concrete inside the form will be about...
I am going to drill little 1/8" holes in the 3/4'' plywood and use them to string brace wire between the two forms. Tighten them real tight with 38" 2x4's next to each. As the concrete is poured, I'll snatch the 2x4's out, leaving only the wires to keep the sides of the forms from bowing. That's...
