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� <br />' ' Grade <br />.�� <br />Calculation: qrade <br />re: <br />9n - <br />support(s) necessary <br />to oppose wind pressure <br />_- - - - - - <br />� as needed. ' <br />Wind Velocity: 80 <br />Formula fcr Section Modulus: W x Fi x C x P z 1.33 x 12 = 36,OP0 x Sectio�, Modulus <br />_ _---- <br />_ _. _ _ _---. ___ <br />�efiniticn of factors: <br />W= w�dth of sign component (feet) ' __ <br />H= width of sign ccmponent (feet) _ ____ ._ _ <br />C= Distance from point of calculalion to center of sign component (feet) �i <br />P = Wind pressure (poundslsquare foot) � <br />1.33 is the allowable stress increase for windload ('J.B.C.) ' <br />12 converts feet to inches , <br />36,000 is minimum tensile strength of slructural steei pbslsq. in.) per American Inst. of Steel Const. <br />iimplified formula for Section Modulus = lN x H x C x P12255 !_ <br />'ormula for Wind Pressure: P= Cq x Ce x Q. <br />Cq = 1.4 (factor for type of structure, 1.4 for flagpoles, signs, etc.) <br />Ca = Exposure factor, from 1997 U.B.C. (see table) <br />Qs = factor for wind velocity, from 1997 U.B.C. (see table) _ <br />°xposure factor table (Ce) I __ _ __ <br />�enter of Siqn Component to grade Exposure B Exposure C __ <br />0-15 feat <br />15-20 feet <br />20-25 feat <br />35-30 feet <br />3;1-40 feet <br />80 miles/hour <br />90 miles/hour <br />100 mileslhour <br />0.62 1.Ofi <br />^.67 1.13 <br />0.72 1 15 <br />0.76 1.23 <br />0.84 1.31 <br />' 20 <br />; �5 <br />i Component "A" 1.4 0.62, ____ 16.4, 14.z3b2 <br />i Component`'B" _ 1.4 0.621 __ __16.4�, 14.2352 <br />— _ _ ; _ _- - —. -, - <br />--' -- --� — _ --�-----•— <br />� , i <br />_ ....... .. . .. „----- ^----��-- �- <br />�� i�EADERBOARD" <br />2.2' 13.9' <br />3.66 11 I <br />tion Modulus <br />14.2352', 2.542 <br />O. - 0.000 <br />_ _ _ _ 0.000 <br />_ <br />Total Section Modulus Required= <br />Section Modulus 6" x 6" x.250"Steel Tube= <br />nu a qau �� <br />Page 1 <br />