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McPherson Engineering By: T.B. <br />Date: 10/11/23 <br />Rooftop Solar Panels Wind Pressures (Section 29.4, ASCE 7-16) <br />Vult =1 0 mph Kzt =ft <br />Exposure Category = C Kz = <br />Roof Zone = 2 Kd = <br />Roof θ = 27-45 deg Ke = <br />1.00 (sec 26.8.2)h = 1 <br />0.85 (sec 26.10.1) <br />0.85 (sec 26.6) <br />1.00 (sec 26.9) <br />qh = 0.00256 Kz Kzt Kd Ke V2 qh =18.50 (eq. 26.10-1) <br />GPp =-2 uplift γE =1.5 (sec 29.4.4) <br />γa =0.77 (fig 29.4-8) <br />γE =1.5 FIG 29.4-7)γc =0.96 (fig 29.4-7)hpt =0 <br />γa =0.77 (fig 29.4-8)γp =0.9 (fig 29.4-7)ω =0.00 deg (panel tilt) <br />GPp =-2 uplift GCrm =1.4 uplift <br />p = qh (GPp) γE γa (eq 29.4-7)p = qh (GCrn) γE γC γp (eq 29.4-6) <br />p =-42.7 p.s.f.p =33.5 p.s.f. <br />Check Anchorage to Existing Structure <br />0.6DL - 0.6W controlling load combination (eq. 16-15 for ASD) <br />DL =2.9 p.s.f.dead load of panel (inlcuding rack system) <br />W = 42.7 p.s.f.wind load normal to face of panel <br />Arealag =12.0 sq. ft.area tributary to each anchor <br />SPanc = .0 ft.spacing of anchors <br />Puplift = Arealag (0.6DL - 0.6W) =284.9 lbs total uplift on anchor <br />Material =DFL lumber anchor material <br />Dialag =5/16 in.diameter of screw <br />Penlag =2.5 in.min. penetration to existing framing <br />W lag =266 lb/in.withdrawal load per in. of penetration per NDS Table 11.2A <br />CD =1.6 load duration factor for wind per NDS Table 2.3.2 <br />Ct =0.8 temperature factor per NDS Table 2.3.3 <br />Noscrews =1 number of screws in withdrawal <br />Pallow = Penlag (Wlag CD Ct) * Noscrews =851.2 lbs total allowable withrawal on anchor <br />Puplift <br />Pallow <br />Anchorage = USE (1) 5/16IN. DIA. LAG <br />Wind Uplift Anchorage <br />Flush Mounted Panels - ASCE Section <br />29.4.4 (where applicable) <br />Flat Roof Panels - ASCE Section 29.4.3 <br />(where applicable) <br />=0.33 < 1.00 Anchor is OK! <br />SCR S 6FT. MAX. O.C. W/ 2.5IN. MIN. PENETRATION <br />10/11/2023 12:22 PM <br />6 of 7 <br />©McPherson Engineering <br />2142 N Spruce St - <br />201820782/22/2024