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Home My WebLink AboutENGINEERING LETTER - 18-00338 - 326 Oaktrail Dr - Solar InstallBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB ŽŵƵƐ^ƚƌƵĐƚƵƌĂůŶŐŝŶĞĞƌŝŶŐ͕>> W͘K͘Žǆϲϵϴϲ ƌŽŽŵĨŝĞůĚ͕KϴϬϬϮϭ ϱϯϬͲϴϲϰͲϳϬϱϱ ŽŵƵƐƐƚƌƵĐƚƵƌĂůΛŐŵĂŝů͘ĐŽŵ dŽ͗ ůƵĞZĂǀĞŶ^ŽůĂƌ ϭϮϮϬ^͘ϲϯϬ͘^ƚĞ͘ϰϯϬ ŵĞƌŝĐĂŶ&ŽƌŬ͕hd͘ϴϰϬϬϯ ^ƵďũĞĐƚ͗ ĞƌƚŝĨŝĐĂƚŝŽŶ>ĞƚƚĞƌ zŽƐƚZĞƐŝĚĞŶĐĞ ϯϮϲKĂŬƚƌĂŝůƌ͘ ZĞǆďƵƌŐ͕/͘ϴϯϰϰϬ dŽtŚŽŵ/ƚDĂǇŽŶĐĞƌŶ͕ ĞƐŝŐŶƌŝƚĞƌŝĂ͗ භ ƉƉůŝĐĂďůĞŽĚĞƐсϮϬϭϱ/ͬ/Z͕^ϳͲϭϬ͕ĂŶĚE^ͲϭϮ භ ZŽŽĨĞĂĚ>ŽĂĚсϳƉƐĨ;DWϭͿ භ ZŽŽĨ>ŝǀĞ>ŽĂĚсϮϬƉƐĨ භ tŝŶĚ^ƉĞĞĚсϭϭϱŵƉŚ͕ǆƉŽƐƵƌĞ භ භ ƚƚĂĐŚŵĞŶƚƐ͗;ϭͿϱͬϭϲΗĚŝĂůĂŐƐĐƌĞǁǁŝƚŚϮ͘ϱΗŵŝŶĞŵďĞĚŵĞŶƚĚĞƉƚŚ͕ĂƚƐƉĂĐŝŶŐƐŚŽǁŶĂďŽǀĞ͘ ^ŝŶĐĞƌĞůǇ͕ :ŽŚŶĂůǀĞƌƚ͕W͘͘ WƌŽũĞĐƚŶŐŝŶĞĞƌ :ƵŶĞϮϬ͕ϮϬϭϴ dŚĞƌŽŽĨƐƚƌƵĐƚƵƌĞŽĨ;DWϭͿĐŽŶƐŝƐƚƐŽĨĐŽŵƉŽƐŝƚŝŽŶƐŚŝŶŐůĞŽŶƌŽŽĨƉůǇǁŽŽĚƚŚĂƚŝƐƐƵƉƉŽƌƚĞĚďǇƉƌĞͲŵĂŶƵĨĂĐƚƵƌĞĚƚƌƵƐƐĞƐƚŚĂƚ ĂƌĞƐƉĂĐĞĚĂƚΛϮϰΗŽ͘Đ͘͘dŚĞƚŽƉĐŚŽƌĚƐ͕ƐůŽƉĞĚĂƚϮϲĚĞŐƌĞĞƐ͕ĂƌĞϮǆϰƐĞĐƚŝŽŶƐ͕ƚŚĞďŽƚƚŽŵĐŚŽƌĚƐĂƌĞϮǆϰƐĞĐƚŝŽŶƐĂŶĚƚŚĞǁĞď ŵĞŵďĞƌƐĂƌĞϮǆϰƐĞĐƚŝŽŶƐ͘dŚĞƚƌƵƐƐŵĞŵďĞƌƐĂƌĞĐŽŶŶĞĐƚĞĚďǇƐƚĞĞůŐƵƐƐĞƚƉůĂƚĞƐ͘dŚĞŵĂǆƵŶƐƵƉƉŽƌƚĞĚƉƌŽũĞĐƚĞĚŚŽƌŝǌŽŶƚĂů ƚŽƉĐŚŽƌĚƐƉĂŶŝƐĂƉƉƌŽǆŝŵĂƚĞůǇϲΖͲϬΖΖ͘ dŚĞĞǆŝƐƚŝŶŐƌŽŽĨĨƌĂŵŝŶŐƐǇƐƚĞŵŽĨ;DWϭͿŝƐũƵĚŐĞĚƚŽďĞĂĚĞƋƵĂƚĞƚŽǁŝƚŚƐƚĂŶĚƚŚĞůŽĂĚŝŶŐŝŵƉŽƐĞĚďǇƚŚĞŝŶƐƚĂůůĂƚŝŽŶŽĨƚŚĞ ƐŽůĂƌƉĂŶĞůƐ͘EŽƌĞŝŶĨŽƌĐĞŵĞŶƚŝƐŶĞĐĞƐƐĂƌǇ͘ 'ƌŽƵŶĚ^ŶŽǁ>ŽĂĚсϱϬƉƐĨͲZŽŽĨ^ŶŽǁ>ŽĂĚсϯϱƉƐĨ dŚĞƐƉĂĐŝŶŐŽĨƚŚĞƐŽůĂƌƐƚĂŶĚŽĨĨƐƐŚŽƵůĚďĞŬĞƉƚĂƚϰϴΗŽ͘Đ͘ĨŽƌůĂŶĚƐĐĂƉĞĂŶĚϰϴΗŽ͘Đ͘ĨŽƌƉŽƌƚƌĂŝƚŽƌŝĞŶƚĂƚŝŽŶ͕ǁŝƚŚĂƐƚĂŐŐĞƌĞĚ ƉĂƚƚĞƌŶƚŽĞŶƐƵƌĞƉƌŽƉĞƌĚŝƐƚƌŝďƵƚŝŽŶŽĨůŽĂĚƐ͘ ũŽďƐŝƚĞŽďƐĞƌǀĂƚŝŽŶŽĨƚŚĞĐŽŶĚŝƚŝŽŶŽĨƚŚĞĞǆŝƐƚŝŶŐĨƌĂŵŝŶŐƐǇƐƚĞŵǁĂƐƉĞƌĨŽƌŵĞĚďǇĂŶĂƵĚŝƚƚĞĂŵŽĨůƵĞZĂǀĞŶ^ŽůĂƌĂƐĂ ƌĞƋƵĞƐƚĨƌŽŵŽŵƵƐ^ƚƌƵĐƚƵƌĂůŶŐŝŶĞĞƌŝŶŐ͘ůůƌĞǀŝĞǁŝƐďĂƐĞĚŽŶƚŚĞƐĞŽďƐĞƌǀĂƚŝŽŶƐĂŶĚƚŚĞĚĞƐŝŐŶĐƌŝƚĞƌŝĂůŝƐƚĞĚďĞůŽǁĂŶĚ ŽŶůǇĚĞĞŵĞĚǀĂůŝĚŝĨƉƌŽǀŝĚĞĚŝŶĨŽƌŵĂƚŝŽŶŝƐƚƌƵĞĂŶĚĂĐĐƵƌĂƚĞ͘ KŶƚŚĞĂďŽǀĞƌĞĨĞƌĞŶĐĞĚƉƌŽũĞĐƚ͕ƚŚĞƌŽŽĨƐƚƌƵĐƚƵƌĂůĨƌĂŵŝŶŐŚĂƐďĞĞŶƌĞǀŝĞǁĞĚĨŽƌĂĚĚŝƚŝŽŶĂůůŽĂĚŝŶŐĚƵĞƚŽƚŚĞŝŶƐƚĂůůĂƚŝŽŶŽĨ ƚŚĞƐŽůĂƌWsĂĚĚŝƚŝŽŶƚŽƚŚĞƌŽŽĨ͘dŚĞƐƚƌƵĐƚƵƌĂůƌĞǀŝĞǁŽŶůǇĂƉƉůǇƐƚŽƚŚĞƐĞĐƚŝŽŶŽĨƚŚĞƌŽŽĨƚŚĂƚŝƐĚŝƌĞĐƚůǇƐƵƉƉŽƌƚŝŶŐƚŚĞƐŽůĂƌ WsƐǇƐƚĞŵĂŶĚŝƚƐƐƵƉƉŽƌƚŝŶŐĞůĞŵĞŶƚƐ͘dŚĞŽďƐĞƌǀĞĚƌŽŽĨĨƌĂŵŝŶŐŝƐĚĞƐĐƌŝďĞĚďĞůŽǁ͘/ĨĨŝĞůĚĐŽŶĚŝƚŝŽŶƐĚŝĨĨĞƌ͕ĐŽŶƚƌĂĐƚŽƌƚŽ ŶŽƚŝĨǇĞŶŐŝŶĞĞƌƉƌŝŽƌƚŽƐƚĂƌƚŝŶŐĐŽŶƐƚƌƵĐƚŝŽŶ͘ dŚĞƐĐŽƉĞŽĨƚŚŝƐƌĞƉŽƌƚŝƐƐƚƌŝĐƚůǇůŝŵŝƚĞĚƚŽĂŶĞǀĂůƵĂƚŝŽŶŽĨƚŚĞĨĂƐƚĞŶĞƌĂƚƚĂĐŚŵĞŶƚ͕ƵŶĚĞƌůǇŝŶŐĨƌĂŵŝŶŐĂŶĚƐƵƉƉŽƌƚŝŶŐ ƐƚƌƵĐƚƵƌĞŽŶůǇ͘dŚĞĂƚƚĂĐŚŵĞŶƚΖƐƚŽƚŚĞĞǆŝƐƚŝŶŐƐƚƌƵĐƚƵƌĞĂƌĞƌĞƋƵŝƌĞĚƚŽďĞŝŶĂƐƚĂŐŐĞƌĞĚƉĂƚƚĞƌŶƚŽĞŶƐƵƌĞƉƌŽƉĞƌĚŝƐƚƌŝďƵƚŝŽŶ ŽĨůŽĂĚŝŶŐ͘ůůƉĂŶĞůƐ͕ƌĂĐŬŝŶŐĂŶĚŚĂƌĚǁĂƌĞƐŚĂůůďĞŝŶƐƚĂůůĞĚƉĞƌŵĂŶƵĨĂĐƚƵƌĞƌƐƉĞĐŝĨŝĐĂƚŝŽŶƐĂŶĚǁŝƚŚŝŶƐƉĞĐŝĨŝĞĚĚĞƐŝŐŶ ůŝŵŝƚĂƚŝŽŶƐ͘ůůǁĂƚĞƌƉƌŽŽĨŝŶŐƐŚĂůůďĞƉƌŽǀŝĚĞĚďǇƚŚĞŵĂŶƵĨĂĐƚƵƌĞƌ͘ŽŵƵƐ^ƚƌƵĐƚƵƌĂůŶŐŝŶĞĞƌŝŶŐĂƐƐƵŵĞƐŶŽƌĞƐƉŽŶƐŝďŝůŝƚǇĨŽƌ ŵŝƐƵƐĞŽƌŝŵƉƌŽƉĞƌŝŶƐƚĂůůĂƚŝŽŶŽĨƚŚĞƐŽůĂƌWsƉĂŶĞůƐŽƌƌĂĐŬŝŶŐ͘ WůĞĂƐĞĐŽŶƚĂĐƚŵĞǁŝƚŚĂŶǇĨƵƌƚŚĞƌƋƵĞƐƚŝŽŶƐŽƌĐŽŶĐĞƌŶƐƌĞŐĂƌĚŝŶŐƚŚŝƐƉƌŽũĞĐƚ͘ <RVW5HVLGHQFH5H[EXUJ,' Digitally signed by John Calvert Date: 2018.06.20 14:56:50 -06'00' ͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺ ŽŵƵƐ^ƚƌƵĐƚƵƌĂůŶŐŝŶĞĞƌŝŶŐ͕>> W͘K͘Žǆϲϵϴϲ ƌŽŽŵĨŝĞůĚ͕KϴϬϬϮϭ ϱϯϬͲϴϲϰͲϳϬϱϱ ŽŵƵƐƐƚƌƵĐƚƵƌĂůΛŐŵĂŝů͘ĐŽŵ Address: 326 Oaktrail Dr., Rexburg, ID. 83440 Exposure: C Wind Speed: 115 mph Risk Category: II Aerial Image <RVW5HVLGHQFH5H[EXUJ,' ͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺ ŽŵƵƐ^ƚƌƵĐƚƵƌĂůŶŐŝŶĞĞƌŝŶŐ͕>> W͘K͘Žǆϲϵϴϲ ƌŽŽŵĨŝĞůĚ͕KϴϬϬϮϭ ϱϯϬͲϴϲϰͲϳϬϱϱ ŽŵƵƐƐƚƌƵĐƚƵƌĂůΛŐŵĂŝů͘ĐŽŵ 50 psf (ASCE7 - Eq 7-1) 1 (ASCE7 - Table 7-2) 1 (ASCE7 - Table 7-3) 1 35.0 psf (ASCE7 - Eq 7-2) 1 35.0 psf 3.0 psf 4.00 ft 2.67 ft 10.68 sft 32 lb 4.00 2.00 0.73 0.00 (Ceiling Not Vaulted) 0.27 7.0 psf 7.8 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 @ 24"o.c. I = Importance Factor = Cs = Slope Factor = Standoff Tributary Area = ps = Cspf ps = Sloped Roof Snow Load = pf = Flat Roof Snow Load = Roof Snow Load Calculations pg = Ground Snow Load = Ce = Exposure Factor = pf = 0.7 Ce Ct I 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 26 Degree Slope Point Loads of Standoffs Miscellaneous Vaulted Ceiling Total Roof DL (MP1) PV Dead Load = 3 psf (Per Blue Raven Solar) <RVW5HVLGHQFH5H[EXUJ,' BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB ŽŵƵƐ^ƚƌƵĐƚƵƌĂůŶŐŝŶĞĞƌŝŶŐ͕>> W͘K͘Žǆϲϵϴϲ ƌŽŽŵĨŝĞůĚ͕KϴϬϬϮϭ ϱϯϬͲϴϲϰͲϳϬϱϱ ŽŵƵƐƐƚƌƵĐƚƵƌĂůΛŐŵĂŝů͘ĐŽŵ 115 mph C Gable/Hip 26 degrees 20 ft 19.3 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 = -0.86 -1.51 -2.37 0.42 (Fig. 30.4-1) Uplift Pressure = -13.40 psf -23.47 psf -36.86 psf 11.0 psf X Standoff Spacing = 4.00 4.00 2.67 Y Standoff Spacing = 2.67 2.67 2.67 Tributary Area = 10.68 10.68 7.12 Footing Uplift = -143 lb -251 lb -262 lb Zone 1 Zone 2 Zone 3 Positive GCp = -0.86 -1.51 -2.37 0.42 (Fig. 30.4-1) Uplift Pressure = -13.40 psf -23.47 psf -36.86 psf 10.0 psf (Minimum) X Standoff Spacing = 4.00 4.00 2.67 Y Standoff Spacing = 1.67 1.67 1.67 Tributary Area = 6.68 6.68 4.45 Footing Uplift = -89 lb -157 lb -164 lb -262 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 > 262 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 > 262 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 <RVW5HVLGHQFH5H[EXUJ,' ͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺͺ ŽŵƵƐ^ƚƌƵĐƚƵƌĂůŶŐŝŶĞĞƌŝŶŐ͕>> W͘K͘Žǆϲϵϴϲ ƌŽŽŵĨŝĞůĚ͕KϴϬϬϮϭ ϱϯϬͲϴϲϰͲϳϬϱϱ ŽŵƵƐƐƚƌƵĐƚƵƌĂůΛŐŵĂŝů͘ĐŽŵ Framing Information & Site Specific Pictures <RVW5HVLGHQFH5H[EXUJ,' BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB ŽŵƵƐ^ƚƌƵĐƚƵƌĂůŶŐŝŶĞĞƌŝŶŐ͕>> W͘K͘Žǆϲϵϴϲ ƌŽŽŵĨŝĞůĚ͕KϴϬϬϮϭ ϱϯϬͲϴϲϰͲϳϬϱϱ ŽŵƵƐƐƚƌƵĐƚƵƌĂůΛŐŵĂŝů͘ĐŽŵ 03PASS Dead Load 7.8 psf PV Load 3.0 psf Snow Load 35.0 psf Governing Load Combo = DL + SL Total Load 45.8 psf Fb (psi) = f'b x Cd x Cf x Cr (NDS Table 4.3.1) 900 x 1.15 x 1.5 x 1.15 Allowed Bending Stress = 1785.3 psi (wL^2) / 8 = 412.094 ft# = 4945.13 in# Actual Bending Stress = (Maximum Moment) / S = 1614.8 psi L/180 (E = 1600000 psi Per NDS) = 0.4 in Deflection Criteria Based on = (w*L^4) / (185*E*I) = = L/554 > L/180 Therefore OK Allowed Deflection (Live Load) =L/240 0.3 in (w*L^4) / (185*E*I) L/728 > L/240 Therefore OK Member Area = Fv (psi) = 180 psi (NDS Table 4A) Allowed Shear = Fv * A = Max Shear (V) = w * L / 2 = 275 lb )UDPLQJ&KHFN 2x4 Top Chords @ 24"o.c. Member Span = 6' - 0" 5.3 in^2 Check Shear w = 92 plf (True Dimensions) 945 lb Allowed > Actual -- 29.1% Stressed -- Therefore, OK DF#2 Member Spacing @ 24"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 -- 90.5% Stressed -- Therefore, OK Member Properties Member Size 2x4 S (in^3) 3.06 0.099 in Check Bending Stress Continuous Span 0.130 in <RVW5HVLGHQFH5H[EXUJ,' BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB B ŽŵƵƐ^ƚƌƵĐƚƵƌĂůŶŐŝŶĞĞƌŝŶŐ͕>> W͘K͘Žǆϲϵϴϲ ƌŽŽŵĨŝĞůĚ͕KϴϬϬϮϭ ϱϯϬͲϴϲϰͲϳϬϱϱ ŽŵƵƐƐƚƌƵĐƚƵƌĂůΛŐŵĂŝů͘ĐŽŵ Level Area Weight (psf) Weight (lb) Roof 2300 sf 7.8 psf 17913 lb Ceiling 2300 sf 6.0 psf 13800 lb Wood Siding 100 ft 5.0 psf 2000 lb (8'-0" Wall Height) Int. Walls 100 ft 6.4 psf 2560 lb 36273 lb 3.0 psf 251 sf 753 lb 3627 lb 753 lb 2.1% /DWHUDO&KHFN 3627 lb > 753 lb, Therefore OK 3HU,%&&KDSWHU Existing Weight of Effected Building Existing Weight of Effected Building Proposed Weight of PV System Weight of PV System (Per Blue Raven Solar) Approx. Area of Proposed PV System Approximate Total Weight of PV System 10% Comparison 10% of Existing Building Weight (Allowed) Approximate Weight of PV System (Actual) Percent Increase <RVW5HVLGHQFH5H[EXUJ,'