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HomeMy WebLinkAboutLA184966 - Approved Forbord_Structural Calc_StampedSolar Connection, Inc. 6254 34th Ave NW, Suite A Rochester, MN, 55901 Attn.: To Whom It May Concern re: Job 20-08474 : Tara And Will Forbord Prepared By: PZSE, Inc. - Structural Engineers Roseville, CA October 12, 2020 If you have any questions on the above, do not hesitate to call. The following calculations are for the structural engineering design of the photovoltaic panels located at 21285 Inspiration Ct, Lakeville, MN 55044. After review, PZSE, Inc. certifies that the roof structure has sufficient structural capacity for the applied PV loads. Gravity Loading Project: Tara And Will Forbord -- Job #: 20-08474 Date: 10/12/2020 Engineer: PZSE 50 psf 0.9 (ASCE7 - Table 7-2) 1.1 (ASCE7 - Table 7-3) 1 35 psf (ASCE7 - Eq 7-1) N/A N/A 35 psf (ASCE7 - Eq 7-2) 0.925 ARRAY 1 0.925 ARRAY 2 35.0 psf ARRAY 1 35.0 psf ARRAY 2 16.21 psf ARRAY 1 16.21 psf ARRAY 2 2.00 1.50 0.76 0.00 Ceiling Not Vaulted 0.74 5.0 psf 6.0 psf 2.00 1.50 0.76 0.00 Ceiling Not Vaulted 0.74 5.0 psf 6.0 psf PV Dead Load = 3 psf (Per Solar Connection, Inc.) Note: Roof live load is removed in area's covered by PV array. 2x6 Top Chords @ 24"o.c. Miscellaneous Total Roof DL ARRAY 2 Composition Shingle DL Adjusted to 33 Degree Slope DL Adjusted to 33 Degree Slope Miscellaneous Vaulted Ceiling Roof Dead Load ARRAY 2 Composition Shingle Total Roof DL ARRAY 1 Roof Plywood Vaulted Ceiling Roof Plywood pf = 0.7 Ce Ct I pg where pg ≤ 20 psf, Pf min = I x pg = where pg > 20 psf, Pf min = 20 x I = Therefore, pf = Flat Roof Snow Load = ps = Cspf Ps = Sloped Roof Snow Load = Ps = Sloped Roof Snow Load = Cs = Slope Factor = Cs = Slope Factor = Roof Live Load = Roof Dead Load ARRAY 1 2x6 Top Chords @ 24"o.c. Roof Snow Load Calculations pg = Ground Snow Load = Ce = Exposure Factor = Ct = Thermal Factor = I = Importance Factor = Roof Live Load = Per ASCE 7-16, minimum values of Pf shall apply to hip and gable roofs with slopes less than 15◦. 2 of 6 Wind Calculations Project: Tara And Will Forbord -- Job #: 20-08474 Date: 10/12/2020 Engineer: PZSE 109 mph C Gable 33 degrees 24 ft 48 ft 10.9 sf 4.8 ft 8.2 ft Zone 2 Pressure Equalization Factor,γa 0.78 Eq. 26.10-1 0.932 (Table 30.3-1) 1 (Fig. 26.8-1) 0.85 (Table 26.6-1) 1 (29.4.4) 109 mph (Fig. 26.5-1A) II (Table 1.5-1) qh = 24.1 psf 14.46 Zone 1 Zone 2 Zone 3 Positive GCp =-1.76 -1.97 -2.45 0.88 Uplift Pressure =-19.87 psf -22.22 psf -27.68 psf 21.32 psf Uplift Edge Pressure=-29.80 psf -33.33 psf -41.52 psf 31.98 psf Attachment Dead Load =3.00 psf 3.00 psf 3.00 psf Max Rail Span Length =4.00 4.00 4.00 Max Rail Span Length Edge =4.00 4.00 4.00 Longitudinal Length =2.73 2.73 2.73 Attachment Tributary Area =10.92 10.92 10.92 Attachment Tributary Area Edge =10.92 10.92 10.92 Attachment Uplift =-197.00 -223.00 -283.00 Attachment Uplift Edge=-306 -344 -434 Fastener =5/16 inch Number of Fasteners =1 Minimum Threaded Embedment Depth =2.5 inch Withdraw Capacity Per Inch =205 lb (NDS Eq 12.2-1) Allowable Withdraw Capacity =820 lb (NDS Eq 11.3-1) Therefore, OK Embedment Depth Reduction Factor 1 Lateral Force from Gravity Loads=226 lb Attachment Lateral Capacity =288 lb (NDS Table 12K) 288 lb capacity > 226 lb demand Therefore, OK Design Wind Pressure Calculations Ke (Elevation Factor)= Controlling C&C Wind Zone Wind Pressure P = qh*(G*Cp)*γe*γa Lag Screw Shear Capacity Check 820 lb capacity > 434 lb demand Lag Screw Uplift Capacity Check Risk Category = 0.6 * qh = Per ASCE 7-16 Components and Cladding Effective Wind Area Building Least Width Roof Zone Edge Distance, a Standoff Uplift Calculations Kz (Exposure Coefficient) = Kzt (topographic factor) = Kd (Wind Directionality Factor) = V (Design Wind Speed) = qh = 0.00256 * Kz * Kzt * Kd *Ke* V^2 Array Edge Factor Length Input Variables Wind Speed Exposure Category Roof Shape Mean Roof Height Roof Slope 3 of 6 Framing Check Project: Tara And Will Forbord -- Job #: 20-08474 Date: 10/12/2020 Engineer: PZSE ARRAY 1 PASS Dead Load 6.0 psf PV Load 3.0 psf Snow Load 35.0 psf Governing Load Comb.DL + SL Total Load 44.0 psf Fb (psi) =f'b x Cd x Cf x Cr (NDS Table 4.3.1) 1250 x 1.15 x 1.3 x 1.15 Allowed Bending Stress = 2149 psi (wL^2) / 8 =992.75 ft# = 11913 in# Actual Bending Stress = (Maximum Moment) / S = 1575.3 psi L/180 (E = 1500000 psi Per NDS) =0.633 in Deflection Criteria Based on = (w*L^4) / (185*E*I) = =L/927 <L/180 Therefore OK Allowed Deflection (Live Load) =L/240 0.475 in (w*L^4) / (185*E*I) L/667 <L/240 Therefore OK Member Area =Fv (psi) =135 psi (NDS Table 4A) Allowed Shear = Fv * A =Max Shear (V) = w * L / 2 =418 lb 2x6 Top Chords @ 24"o.c. Check Deflection Check Bending Stress Allowed Deflection (Total Load) = Member Span = 9' - 6" Note: Attachments shall be Staggered. Member Size 2x6 S (in^3) 7.56 I (in^4) 20.80 Lumber Sp/Gr 0.171 in w = 88 plf Member Properties Actual Deflection (Total Load) = Allowed > Actual -- 73.4% Stressed -- Therefore, OK 0.123 in SPFSS Member Spacing @ 24" o.c. Maximum Moment = (True Dimensions) 8.3 in^2 Actual Deflection (Live Load) = Allowed > Actual -- 37.6% Stressed -- Therefore, OK Check Shear 1114 lb Continuous Span 4 of 6 Framing Check Project: Tara And Will Forbord -- Job #: 20-08474 Date: 10/12/2020 Engineer: PZSE ARRAY 2 PASS Dead Load 6.0 psf PV Load 3.0 psf Snow Load 35.0 psf Governing Load Comb.DL + SL Total Load 44.0 psf Fb (psi) =f'b x Cd x Cf x Cr (NDS Table 4.3.1) 875 x 1.15 x 1.3 x 1.15 Allowed Bending Stress = 1504.3 psi (wL^2) / 8 =385.076 ft# = 4620.92 in# Actual Bending Stress = (Maximum Moment) / S = 611.1 psi L/180 (E = 1400000 psi Per NDS) =0.394 in Deflection Criteria Based on = (w*L^4) / (185*E*I) = =L/3550 <L/180 Therefore OK Allowed Deflection (Live Load) =L/240 0.295 in (w*L^4) / (185*E*I) L/1420 <L/240 Therefore OK Member Area =Fv (psi) =135 psi (NDS Table 4A) Allowed Shear = Fv * A =Max Shear (V) = w * L / 2 =260 lb 2x6 (True Dimensions) w = 88 plf 2x6 Top Chords @ 24"o.c. Member Properties Lumber Sp/Gr 0.050 in 0.020 in Member Span = 5' - 11" Member Spacing 8.3 in^2 Actual Deflection (Live Load) = 1114 lb Check Shear Member Size S (in^3)I (in^4) Check Bending Stress Maximum Moment = Allowed > Actual -- 40.7% Stressed -- Therefore, OK Check Deflection @ 24" o.c.7.56 20.80 SPF#2 Allowed Deflection (Total Load) = Actual Deflection (Total Load) = Continuous Span Note: Attachments shall be Staggered. Allowed > Actual -- 23.4% Stressed -- Therefore, OK 5 of 6 Project: Tara And Will Forbord -- Job #: 20-08474 Date: 10/12/2020 Engineer: PZSE Level Area Weight (psf) Weight (lb) Roof 3552 sf 6.0 psf 21312 lb Ceiling 3552 sf 6.0 psf 21312 lb Vinyl Siding 1952 sf 2.0 psf 3904 lb (16' Wall Height) Int. Walls 976 sf 6.0 psf 5856 lb 52384 lb 3.0 psf 817 sf 2451 lb 5238 lb 2451 lb 4.7% Per 2018 IEBC §402.4, the increase in the lateral demand/capacity ratio of the existing structure due to the installation of the PV system is less than 10%. Therefore, the existing structure may remain unaltered. 5238 lb > 2451 lb, Therefore OK Lateral Check: 2018 IEBC Existing Weight of Effected Building Existing Weight of Effected Building Proposed Weight of PV System Weight of PV System (Per Solar Connection, Inc.) 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 6 of 6