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Changes in ASCE 7-10 that coordinate with the introduction of new maps inClUde: 1) revised <br />wind speed triggers defining hurricane prone regions and wind-borne debris regions, and 2) <br />revised pressure values for minimums design loads. Model building codes and standards that rely <br />on the new wind design approach in ASCE 7-10 include the 2012 International Residential Code <br />(IRC), the 2012 IBC, and the 2012 WFCM, however, each of these documents addresses <br />implementation of ASCE 7-10 wind provisions differently. <br />DESIGN VELOCITY PRESSURE' EXAMPLE <br />Design velocity pressures calculated herein are intended to allow comparison of ASCE 7-10 and <br />ASCE 7-05 and represent factored pressures from use of ASD or LRFD load combinations <br />contained in ASCE 7. <br />ASCE, 7-05 Veloeity Pressure <br />q05 =0.00256KK,,K,1V11 (Eq. 1) <br />where: <br />q,o5 = ASCE 7-05 velocity pressure evaluated at mean roof height (psf) <br />K, = velocity pressure exposure coefficient <br />& = topographic factor <br />K,j = wind directionality factor <br />V = basic wind speed (mph) frorn ASCE 7-05 snaps <br />I= finportance factor (1.0 for Category 11 buildings, 1,15 for Category III and IV buildings) <br />Design velocity pressure for ASD and LRFD are: <br />ASD: q7O5_ASD = (1.0)(+o5) (Eq, 2) <br />LRFD: q�.,05JRFD = (1.6)(q,05) (Eq. 3) <br />where: <br />1.0 ASCE 7-05 ASD load factor for wind <br />1.6 ASCE 7-05 LRFD load factor for wind <br />ASCE, 7-10 Velocity Pressure <br />qz 10 0. 0025 6K� K, K,1 j72 (Eq. 4) <br />where: <br />q,10 = ASCE 7-10 velocity pressure evaluated at inean roof height (psf) <br />K, = velocity pressure exposure coefficient <br />K, = topographic factor <br />K,j = wind directionality factor <br />V = basic wind speed (mph) from ASCE 7-10 snaps referred to as ultimate wind speed snaps <br />in 20'12 IBC. <br />ASCE 7-10 Wind Provisions 2 LinelCoulbourne <br />