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HomeMy WebLinkAboutLeo Bonventura Engineering LetterBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB 'RPXV6WUXFWXUDO(QJLQHHULQJ//& 32%R[ %URRPILHOG&2  'RPXVVWUXFWXUDO#JPDLOFRP dŽ͗ ůƵĞZĂǀĞŶ^ŽůĂƌ ϭϰϬϯEŽƌƚŚZĞƐĞĂƌĐŚtĂLJ͕ƵŝůĚŝŶŐ: KƌĞŵ͕hd͘ϴϰϬϵϳ ^ƵďũĞĐƚ͗ ĞƌƚŝĨŝĐĂƚŝŽŶ>ĞƚƚĞƌ ŽŶĂǀĞŶƚƵƌĂZĞƐŝĚĞŶĐĞ ϮϮϭϱdĂŵK^ŚĂŶƚĞƌƚ͘ ĂƌŵĞů͕/E͘ϰϲϬϯϮ dŽtŚŽŵ/ƚDĂLJŽŶĐĞƌŶ͕ ĞƐŝŐŶƌŝƚĞƌŝĂ͗ භ ƉƉůŝĐĂďůĞŽĚĞƐсϮϬϭϰ/ŶĚŝĂŶĂ^ƚĂƚĞƵŝůĚŝŶŐŽĚĞ͕^ϳͲϭϬ භ ZŽŽĨĞĂĚ>ŽĂĚсϴƉƐĨ;DWϭͿ භ ZŽŽĨ>ŝǀĞ>ŽĂĚсϮϬƉƐĨ භ tŝŶĚ^ƉĞĞĚсϭϭϱŵƉŚ;sƵůƚͿ͕džƉŽƐƵƌĞ͕ZŝƐŬĂƚĞŐŽƌLJ// භ භ ^ŝŶĐĞƌĞůLJ͕ :ŽŚŶĂůǀĞƌƚ͕W͘͘ WƌŽũĞĐƚŶŐŝŶĞĞƌ ^ĞƉƚĞŵďĞƌϮϰ͕ϮϬϮϭ dŚĞƌŽŽĨƐƚƌƵĐƚƵƌĞŽĨ;DWϭͿĐŽŶƐŝƐƚƐŽĨĐŽŵƉŽƐŝƚŝŽŶƐŚŝŶŐůĞŽŶƌŽŽĨƉůLJǁŽŽĚƚŚĂƚŝƐƐƵƉƉŽƌƚĞĚďLJƉƌĞͲŵĂŶƵĨĂĐƚƵƌĞĚƚƌƵƐƐĞƐƚŚĂƚ ĂƌĞƐƉĂĐĞĚĂƚΛϭϲΗŽ͘Đ͘͘dŚĞƚŽƉĐŚŽƌĚƐ͕ƐůŽƉĞĚĂƚϰϬĚĞŐƌĞĞƐ͕ĂƌĞϮdžϰƐĞĐƚŝŽŶƐ͕ƚŚĞďŽƚƚŽŵĐŚŽƌĚƐĂƌĞϮdžϰƐĞĐƚŝŽŶƐĂŶĚƚŚĞǁĞď ŵĞŵďĞƌƐĂƌĞϮdžϰƐĞĐƚŝŽŶƐ͘dŚĞƚƌƵƐƐŵĞŵďĞƌƐĂƌĞĐŽŶŶĞĐƚĞĚďLJƐƚĞĞůŐƵƐƐĞƚƉůĂƚĞƐ͘dŚĞŵĂdžƵŶƐƵƉƉŽƌƚĞĚƉƌŽũĞĐƚĞĚŚŽƌŝnjŽŶƚĂů ƚŽƉĐŚŽƌĚƐƉĂŶŝƐĂƉƉƌŽdžŝŵĂƚĞůLJϳΖͲϬΖΖ͘ dŚĞĞdžŝƐƚŝŶŐƌŽŽĨĨƌĂŵŝŶŐƐLJƐƚĞŵŽĨ;DWϭͿŝƐũƵĚŐĞĚƚŽďĞĂĚĞƋƵĂƚĞƚŽǁŝƚŚƐƚĂŶĚƚŚĞůŽĂĚŝŶŐŝŵƉŽƐĞĚďLJƚŚĞŝŶƐƚĂůůĂƚŝŽŶŽĨƚŚĞ ƐŽůĂƌƉĂŶĞůƐ͘EŽƌĞŝŶĨŽƌĐĞŵĞŶƚŝƐŶĞĐĞƐƐĂƌLJ͘ 'ƌŽƵŶĚ^ŶŽǁ>ŽĂĚсϮϬƉƐĨͲZŽŽĨ^ŶŽǁ>ŽĂĚсϭϰƉƐĨ dŚĞƐƉĂĐŝŶŐŽĨƚŚĞƐŽůĂƌƐƚĂŶĚŽĨĨƐƐŚŽƵůĚďĞŬĞƉƚĂƚϲϰΗŽ͘Đ͘ĨŽƌůĂŶĚƐĐĂƉĞĂŶĚϰϴΗŽ͘Đ͘ĨŽƌƉŽƌƚƌĂŝƚŽƌŝĞŶƚĂƚŝŽŶ͕ǁŝƚŚĂƐƚĂŐŐĞƌĞĚ ƉĂƚƚĞƌŶƚŽĞŶƐƵƌĞƉƌŽƉĞƌĚŝƐƚƌŝďƵƚŝŽŶŽĨůŽĂĚƐ͘ ũŽďƐŝƚĞŽďƐĞƌǀĂƚŝŽŶŽĨƚŚĞĐŽŶĚŝƚŝŽŶŽĨƚŚĞĞdžŝƐƚŝŶŐĨƌĂŵŝŶŐƐLJƐƚĞŵǁĂƐƉĞƌĨŽƌŵĞĚďLJĂŶĂƵĚŝƚƚĞĂŵŽĨůƵĞZĂǀĞŶ^ŽůĂƌĂƐĂ ƌĞƋƵĞƐƚĨƌŽŵŽŵƵƐ^ƚƌƵĐƚƵƌĂůŶŐŝŶĞĞƌŝŶŐ͘ůůƌĞǀŝĞǁŝƐďĂƐĞĚŽŶƚŚĞƐĞŽďƐĞƌǀĂƚŝŽŶƐĂŶĚƚŚĞĚĞƐŝŐŶĐƌŝƚĞƌŝĂůŝƐƚĞĚďĞůŽǁĂŶĚ ŽŶůLJĚĞĞŵĞĚǀĂůŝĚŝĨƉƌŽǀŝĚĞĚŝŶĨŽƌŵĂƚŝŽŶŝƐƚƌƵĞĂŶĚĂĐĐƵƌĂƚĞ͘ KŶƚŚĞĂďŽǀĞƌĞĨĞƌĞŶĐĞĚƉƌŽũĞĐƚ͕ƚŚĞƌŽŽĨƐƚƌƵĐƚƵƌĂůĨƌĂŵŝŶŐŚĂƐďĞĞŶƌĞǀŝĞǁĞĚĨŽƌĂĚĚŝƚŝŽŶĂůůŽĂĚŝŶŐĚƵĞƚŽƚŚĞŝŶƐƚĂůůĂƚŝŽŶŽĨ ƚŚĞƐŽůĂƌWsĂĚĚŝƚŝŽŶƚŽƚŚĞƌŽŽĨ͘dŚĞƐƚƌƵĐƚƵƌĂůƌĞǀŝĞǁŽŶůLJĂƉƉůŝĞƐƚŽƚŚĞƐĞĐƚŝŽŶŽĨƚŚĞƌŽŽĨƚŚĂƚŝƐĚŝƌĞĐƚůLJƐƵƉƉŽƌƚŝŶŐƚŚĞƐŽůĂƌ WsƐLJƐƚĞŵĂŶĚŝƚƐƐƵƉƉŽƌƚŝŶŐĞůĞŵĞŶƚƐ͘dŚĞŽďƐĞƌǀĞĚƌŽŽĨĨƌĂŵŝŶŐŝƐĚĞƐĐƌŝďĞĚďĞůŽǁ͘/ĨĨŝĞůĚĐŽŶĚŝƚŝŽŶƐĚŝĨĨĞƌ͕ĐŽŶƚƌĂĐƚŽƌƚŽ ŶŽƚŝĨLJĞŶŐŝŶĞĞƌƉƌŝŽƌƚŽƐƚĂƌƚŝŶŐĐŽŶƐƚƌƵĐƚŝŽŶ͘ dŚĞƐĐŽƉĞŽĨƚŚŝƐƌĞƉŽƌƚŝƐƐƚƌŝĐƚůLJůŝŵŝƚĞĚƚŽĂŶĞǀĂůƵĂƚŝŽŶŽĨƚŚĞĨĂƐƚĞŶĞƌĂƚƚĂĐŚŵĞŶƚ͕ƵŶĚĞƌůLJŝŶŐĨƌĂŵŝŶŐĂŶĚƐƵƉƉŽƌƚŝŶŐ ƐƚƌƵĐƚƵƌĞŽŶůLJ͘dŚĞĂƚƚĂĐŚŵĞŶƚΖƐƚŽƚŚĞĞdžŝƐƚŝŶŐƐƚƌƵĐƚƵƌĞĂƌĞƌĞƋƵŝƌĞĚƚŽďĞŝŶĂƐƚĂŐŐĞƌĞĚƉĂƚƚĞƌŶƚŽĞŶƐƵƌĞƉƌŽƉĞƌĚŝƐƚƌŝďƵƚŝŽŶ ŽĨůŽĂĚŝŶŐ͘ůůƉĂŶĞůƐ͕ƌĂĐŬŝŶŐĂŶĚŚĂƌĚǁĂƌĞƐŚĂůůďĞŝŶƐƚĂůůĞĚƉĞƌŵĂŶƵĨĂĐƚƵƌĞƌƐƉĞĐŝĨŝĐĂƚŝŽŶƐĂŶĚǁŝƚŚŝŶƐƉĞĐŝĨŝĞĚĚĞƐŝŐŶ ůŝŵŝƚĂƚŝŽŶƐ͘ůůǁĂƚĞƌƉƌŽŽĨŝŶŐƐŚĂůůďĞƉƌŽǀŝĚĞĚďLJƚŚĞŵĂŶƵĨĂĐƚƵƌĞƌ͘ŽŵƵƐ^ƚƌƵĐƚƵƌĂůŶŐŝŶĞĞƌŝŶŐĂƐƐƵŵĞƐŶŽƌĞƐƉŽŶƐŝďŝůŝƚLJĨŽƌ ŵŝƐƵƐĞŽƌŝŵƉƌŽƉĞƌŝŶƐƚĂůůĂƚŝŽŶŽĨƚŚĞƐŽůĂƌWsƉĂŶĞůƐŽƌƌĂĐŬŝŶŐ͘ WůĞĂƐĞĐŽŶƚĂĐƚŵĞǁŝƚŚĂŶLJĨƵƌƚŚĞƌƋƵĞƐƚŝŽŶƐŽƌĐŽŶĐĞƌŶƐƌĞŐĂƌĚŝŶŐƚŚŝƐƉƌŽũĞĐƚ͘ EŽƚĞ͗^ĞŝƐŵŝĐĐŚĞĐŬŝƐŶŽƚƌĞƋƵŝƌĞĚƐŝŶĐĞ^Ɛф͘ϰŐĂŶĚ^ĞŝƐŵŝĐĞƐŝŐŶĂƚĞŐŽƌLJ;^Ϳф ƚƚĂĐŚŵĞŶƚ͗ϭͲϱͬϭϲĚŝĂ͘ůĂŐƐĐƌĞǁǁŝƚŚϮ͘ϱŝŶĐŚŵŝŶ͘ĞŵďĞĚŵĞŶƚ ĚĞƉƚŚ͕ĂƚƐƉĂĐŝŶŐƐŚŽǁŶĂďŽǀĞ͘ %RQYHQWXUD&DUPHO,1 Digitally signed by John A. Calvert Date: 2021.09.24 12:38:58 -06'00' ͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺ 'RPXV6WUXFWXUDO(QJLQHHULQJ//& 32%R[ %URRPILHOG&2  'RPXVVWUXFWXUDO#JPDLOFRP 20 psf (ASCE7 - Eq 7-1) 1 (ASCE7 - Table 7-2) 1 (ASCE7 - Table 7-3) 1 14.0 psf (ASCE7 - Eq 7-2) 1 14.0 psf 3.92 psf 3.0 psf 4.00 ft 6.08 ft 24.33 sft 73 lb 4.00 2.00 1.10 0.00 (Ceiling Not Vaulted) 0.90 8.0 psf 10.4 psf *UDYLW\/RDGLQJ PV System Weight Weight of PV System (Per Blue Raven Solar) X Standoff Spacing = Y Standoff Spacing = Note: PV standoffs are staggered to ensure proper distribution of loading 2x4 Top Chords @ 16"o.c. I = Importance Factor = Cs = Slope Factor = Standoff Tributary Area = ps = Cspf ps = Sloped Roof Snow Load = pf = Flat Roof Snow Load = DL Adjusted to 40 Degree Slope Roof Snow Load Calculations pg = Ground Snow Load = Ce = Exposure Factor = pf = 0.7 CeCtI pg Ct = Thermal Factor = Roof Live Load = 20 psf Roof Plywood Roof Dead Load (MP1) Composition Shingle Note: Roof live load is removed in area's covered by PV array. DL Adjusted to 40 Degree Slope Point Loads of Standoffs Miscellaneous Vaulted Ceiling Total Roof DL (MP1) PV Dead Load = 3 psf (Per Blue Raven Solar) %RQYHQWXUD&DUPHO,1 BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB 'RPXV6WUXFWXUDO(QJLQHHULQJ//& 32%R[ %URRPILHOG&2  'RPXVVWUXFWXUDO#JPDLOFRP 115 mph C Hip/Gable 40 degrees 20 ft 21.3 ft (Eq. 30.3-1) 0.9 (Table 30.3-1) 1 (Fig. 26.8-1) 0.85 (Table 26.6-1) 115 mph (Fig. 26.5-1A) II (Table 1.5-1) qh = 25.90 15.54 Zone 1 Zone 2 Zone 3 Positive GCp = -0.94 -1.15 -1.15 0.86 (Fig. 30.4-1) Uplift Pressure = -14.55 psf -17.80 psf -17.80 psf 22.4 psf X Standoff Spacing = 4.00 4.00 2.67 Y Standoff Spacing = 6.08 3.041666667 3.04166667 Tributary Area = 24.33 12.17 8.11 Dead Load on Attachment= 73.00 36.50 24.33 Footing Uplift (0.6D+0.6W)= -310 lb -195 lb -130 lb Zone 1 Zone 2 Zone 3 Positive GCp = -0.94 -1.15 -1.15 0.86 (Fig. 30.4-1) Uplift Pressure = -14.55 psf -17.80 psf -17.80 psf 10.5 psf X Standoff Spacing = 5.33 5.33 3.56 Y Standoff Spacing = 3.50 1.75 1.75 Tributary Area = 18.67 9.33 6.22 Dead Load on Attachment= 56.00 28.00 18.67 Footing Uplift (0.6D+0.6W) = -238 lb -149 lb -100 lb -310 lb 450 lb Therefore, OK Fastener =1 - 5/16" dia. lag Number of Fasteners = 1 Embedment Depth = 2.5 Pullout Capacity Per Inch = 250 lb Fastener Capacity = 625 lb w/ F.S. of 1.5 & DOL of 1.6= 667 lb Therefore, OK :LQG&DOFXODWLRQV Maximum Design Uplift = Standoff Uplift Capacity = 450 lb capacity > 310 lb demand Fastener Capacity Check Standoff Uplift Check Kz (Exposure Coefficient) = Kzt (topographic factor) = Kd (Wind Directionality Factor) = V (Design Wind Speed) = Risk Category = qh = 0.00256 * Kz * Kzt * Kd * V^2 Wind Pressure P = qh*G*Cn Exposure Category WĞƌ^ϳͲϭϬŽŵƉŽŶĞŶƚƐĂŶĚůĂĚĚŝŶŐ Mean Roof Height Roof Slope 667.2 lb capacity > 310 lb demand 0.6 * qh = Standoff Uplift Calculations-Landscape Input Variables Wind Speed Effective Wind Area Design Wind Pressure Calculations Roof Shape Standoff Uplift Calculations-Portrait %RQYHQWXUD&DUPHO,1 BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB 'RPXV6WUXFWXUDO(QJLQHHULQJ//& 32%R[ %URRPILHOG&2  'RPXVVWUXFWXUDO#JPDLOFRP 03 PASS Dead Load 10.4 psf PV Load 3.9 psf Snow Load 14.0 psf Governing Load Combo = DL + LL Total Load 34.4 psf Fb (psi) = f'b x Cd x Cf x Cr (NDS Table 4.3.1) 900 x 1.25 x 1.5 x 1.15 Allowed Bending Stress = 1940.6 psi (wL^2) / 8 = 280.6024 ft# = 3367.229 in# Actual Bending Stress = (Maximum Moment) / S = 1099.6 psi L/180 (E = 1600000 psi Per NDS) = 0.466 in Deflection Criteria Based on = (w*L^4) / (185*E*I) = = L/700 > L/180 Therefore OK Allowed Deflection (Live Load) =L/240 0.35 in (w*L^4) / (185*E*I) L/1200 > L/240 Therefore OK Member Area = Fv (psi) = 180 psi (NDS Table 4A) Allowed Shear = Fv * A =Max Shear (V) = w * L / 2 =160 lb )UDPLQJ&KHFN 5.3 in^2 Check Shear w = 46 plf 2x4 Top Chords @ 16"o.c. Member Span = 7' - 0" 945 lb Allowed > Actual -- 17% Stressed -- Therefore, OK DF#2 Member Spacing @ 16"o.c. Maximum Moment = Check Deflection I (in^4) 5.36 Lumber Sp/Gr Actual Deflection (Live Load)= Allowed Deflection (Total Load) = Actual Deflection (Total Load) = Allowed > Actual -- 56.7% Stressed -- Therefore, OK Member Properties Member Size 2x4 S (in^3) 3.06 0.070 in Continuous Span 0.120 in Check Bending Stress (True Dimensions) %RQYHQWXUD&DUPHO,1