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Diagram <br /> L <br /> CNW CNL <br /> Wind <br /> Direction <br /> => e <br /> y_0o h <br /> Notation <br /> L=Horizontal dimension of roof, measured in the along-wind direction, ft (m). <br /> h=Mean roof height, ft (m). <br /> cd y=Direction of wind, degrees. <br /> 0=Angle of plane of roof from horizontal, degrees. <br /> 0 <br /> Net Pressure Coefficient, CN <br /> 0 <br /> Wind Direction, =0°,18o, <br /> 0 <br /> w <br /> Clear Wind Flow Obstructed Wind Flow <br /> W <br /> U <br /> Roof Angle,B Load Case CNW CNL CNW CNL <br /> bA <br /> 7.5 A 1.1 -0.3 -1.6 -1.0 <br />�j B 0.2 -1.2 -0.9 -1.7 <br /> 00 15' A 1.1 -0.4 -1.2 -1.0 <br /> B 0.1 -1.1 -0.6 -1.6 <br /> N 22.51 A 1.1 0.1 -1.2 -1.2 <br /> B -0.1 -0.8 -0.8 -1.7 <br /> O <br /> 30' A 1.3 0.3 -0.7 -0.7 <br /> c B -0.1 -0.9 -0.2 -1.1 <br /> c 37.5° A 1.3 0.6 -0.6 -0.6 <br /> v B -0.2 -0.6 -0.3 -0.9 <br /> on <br /> 45' A 1.1 0.9 -0.5 -0.5 <br /> o B -0.3 -0.5 -0.3 -0.7 <br /> p <br /> Notes <br /> 0 1. CNw and CNL denote net pressures(contributions from top and bottom surfaces)for windward and leeward half of roof surfaces, <br /> respectively. <br /> 2. Clear wind flow denotes relatively unobstructed wind flow with blockage less than or equal to 50%. Obstructed wind flow <br /> denotes objects below roof inhibiting wind flow (>50% blockage). <br /> 3. For values of 0 between 7.5°and 45°,linear interpolation is permitted.For values of 0 less than 7.5°,use monoslope roof load <br /> Q coefficients. <br /> 4. Plus and minus signs signify pressures acting toward and away from the top roof surface, respectively. <br /> 5. All load cases shown for each roof angle shall be investigated. <br /> FIGURE 27.3-5 Main Wind Force Resisting System, Part 1 (0.25< h/L<1.0): Net Pressure Coefficient, CN, <br /> for Open Buildings with Pitched Free Roofs, 0<45°,y=0°, 1800 <br /> 280 STANDARD ASCE/SEI 7-16 <br />