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Mech'l Unit Anchorage/Support at Roof (AH) <br />ASCE 7-16 Chapter 13, 2018 NDS Allowable Stress Design <br />Unit Weight, Wp =1600 lbs.ap =2.5 <br />Width, W =4.0 ft.Rp =6.0 <br />Length, L =5.0 ft.SDS =1.020 <br />Height to C.M., H =2.0 ft.Ip =1.00 <br />Seismic Design Force: <br />Fp = (0.4 ap SDS Ip)/Rp (1+ 2 z/h)Wp =816 lb <br />Fp (min) = 0.3 SDS Ip Wp =490 lb <br />Fp (max) = 1.6 SDS Ip Wp =2611 lb <br />Fp (required) = 816 lb <br />Anchorage : <br />Anchorage Force = 0.7Fp = 0.7ρQE =571 lb <br />T = C = Fp x H / (W/2) = 143 lb lb/screw <br />PD = Wp / 4 =400 lb <br />Ts = -257 lb No Uplift <br />Vs = 0.7Fp/12 = 48 lb/screw <br />48 lb <br />α = 0.0° <br />For 3/8" dia. Lag Screws w/ 3" Min. Embed <br />W'p = 1.6 x 2.75" x 305 = 1342 lb <br />Z' = 1.6 x 130 = 208 lb Use 3/8" dia. Lag Screw w/ 3" Min. Embed <br />208 lb. > 48 lb. O.K.Min. 3 Ea. Side (12 total) <br />Support @ 48" o/c : <br />Span =8 ft.Summary:CD M </> M all OK/NG <br />wD =15 plf L.C. I 1.25 1880 < 2151 OK <br />wLr =20 plf L.C. II 1.6 2251 < 2753 OK <br />PD = Wp/2 =800 lbs.L.C. III 1.6 2230 < 2753 OK <br />Load Case 1 : D + Lr <br />M =(wD+wLr) x Span2/8 + PD x Span/4 <br />Load Case II : (1.0+0.14S DS )D + 0.7ρQ E M all =Fb x Sx x CF x CD <br />M =(1.0+0.14SDS)wD x Span2/8 + (1.0+0.14SDS)PD x Span/4 Fb =900 psi <br />+ 0.7Fp/2 x H/W x Span/4 Sx =17.65 in3 <br />Load Case III : (1.0+0.10S DS )D + 0.525ρQ E + 0.75L r CF =1.3 <br />M =(1.0+0.10SDS)wD x Span2/8 + (1.0+0.10SDS)PD x Span/4 <br />+ 0.525Fp/2 x H/W x Span/4 + wLr x Span2/8 <br />Use 4x6 <br />=+=22VsTsR <br />= <br />α+α <br />=α 22sinZ'p)cos(W' <br />p)Z'(W'Z' <br />USE 3/8" DIA. LAG SCREW <br />W/ 3" MIN EMBED. <br />MIN. 12 PER A/C UNIT <br />Project: <br />Project No: <br />Sheet No: <br />Date:Calc. By: <br />Page 5