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Home My WebLink AboutShea Residence Carmel IN-S___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 6986 Broomfield, CO 80021 530-864-7055 Domusstructural@gmail.com To: Blue Raven Solar 1403 North Research Way, Building J Orem, UT. 84097 Subject: Certification Letter Shea Residence 5115 Hummingbird Cir. Carmel, IN. 46033 To Whom It May Concern, Design Criteria: ● Applicable Codes = 2014 Indiana State Building Code, ASCE 7‐10 ● Roof Dead Load = 12 psf (MP1) ● Roof Live Load = 20 psf ● Wind Speed = 115 mph (Vult), Exposure C, Risk Category II ● ● Sincerely, John Calvert, P.E. Project Engineer August 7, 2020 The roof structure of (MP1) consists of composition shingle on roof plywood that is supported by 2x6 rafters @ 16"o.c.. The rafters support a vaulted ceiling and have a max projected horizontal span of 12'‐0", with a slope of 45 degrees. The rafters are supported at the ridge by a ridge board and at the eave by a load bearing wall. The existing roof framing system of (MP1) is judged to be adequate to withstand the loading imposed by the installation of the solar panels. No reinforcement is necessary. Ground Snow Load = 20 psf ‐ Roof Snow Load = 14 psf The spacing of the solar standoffs should be kept at 64" o.c. for landscape and 48" o.c. for portrait orientation, with a staggered pattern to ensure proper distribution of loads. A jobsite observation of the condition of the existing framing system was performed by an audit team of Blue Raven Solar as a request from Domus Structural Engineering. All review is based on these observations and the design criteria listed below and only deemed valid if provided information is true and accurate. On the above referenced project, the roof structural framing has been reviewed for additional loading due to the installation of the solar PV addition to the roof. The structural review only applies to the section of the roof that is directly supporting the solar PV system and its supporting elements. The observed roof framing is described below. If field conditions differ, contractor to notify engineer prior to starting construction. The scope of this report is strictly limited to an evaluation of the fastener attachment, underlying framing and supporting structure only. The attachment's to the existing structure are required to be in a staggered pattern to ensure proper distribution of loading. All panels, racking and hardware shall be installed per manufacturer specifications and within specified design limitations. All waterproofing shall be provided by the manufacturer. Domus Structural Engineering assumes no responsibility for misuse or improper installation of the solar PV panels or racking. Please contact me with any further questions or concerns regarding this project. Note: Seismic check is not required since Ss<.4g and Seismic Design Category (SDC) < B Attachments: 1 ‐ 5/16" dia. lag screw with 2.5 inch min embedment depth, at spacing shown above. Shea Residence, Carmel, IN 1 ____________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 6986 Broomfield, CO 80021 530-864-7055 Domusstructural@gmail.com 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 4.24 psf 3.0 psf 4.00 ft 5.50 ft 22.00 sft 66 lb 4.00 2.00 1.72 4.00 0.28 12.0 psf 17.0 psf Gravity Loading 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 2x6 Rafters @ 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 45 Degree Slope 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 45 Degree Slope Point Loads of Standoffs Miscellaneous Vaulted Ceiling Total Roof DL (MP1) PV Dead Load = 3 psf (Per Blue Raven Solar) Shea Residence, Carmel, IN 2 ___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 6986 Broomfield, CO 80021 530-864-7055 Domusstructural@gmail.com 115 mph C Hip/Gable 45 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 = -0.88 -1.08 -1.08 0.84 (Fig. 30.4-1) Uplift Pressure = -13.61 psf -16.72 psf -16.72 psf 21.7 psf X Standoff Spacing = 4.00 4.00 2.67 Y Standoff Spacing = 5.50 2.75 2.75 Tributary Area = 22.00 11.00 7.33 Footing Uplift = -299 lb -184 lb -123 lb Zone 1 Zone 2 Zone 3 Positive GCp = -0.88 -1.08 -1.08 0.84 (Fig. 30.4-1) Uplift Pressure = -13.61 psf -16.72 psf -16.72 psf 10.0 psf (Minimum) 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 Footing Uplift = -254 lb -156 lb -104 lb -299 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 Wind Calculations Maximum Design Uplift = Standoff Uplift Capacity = 450 lb capacity > 299 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 Per ASCE 7‐10 Components and Cladding Mean Roof Height Roof Slope 667.2 lb capacity > 299 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 Shea Residence, Carmel, IN 3 ___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 6986 Broomfield, CO 80021 530-864-7055 Domusstructural@gmail.com (MP1)PASS Dead Load 17.0 psf PV Load 4.2 psf Snow Load 14.0 psf Governing Load Combo = DL + LL Total Load 41.2 psf Fb (psi) = f'b x Cd x Cf x Cr (NDS Table 4.3.1) 900 x 1.25 x 1.3 x 1.15 Allowed Bending Stress = 1681.8 psi (wL^2) / 8 = 989.117 ft# = 11869.4 in# Actual Bending Stress = (Maximum Moment) / S = 1569.6 psi L/180 (E = 1600000 psi Per NDS) = 0.8 in Deflection Criteria Based on = (w*L^4) / (185*E*I) = = L/450 > L/180 Therefore OK Allowed Deflection (Live Load) =L/240 0.6 in (w*L^4) / (185*E*I) L/924 > L/240 Therefore OK Member Area = Fv (psi) = 180 psi (NDS Table 4A) Allowed Shear = Fv * A =Max Shear (V) = w * L / 2 =330 lb Framing Check 8.3 in^2 Check Shear w = 55 plf 2x6 Rafters @ 16"o.c. Member Span = 12' - 0" 1485 lb Allowed > Actual -- 22.3% Stressed -- Therefore, OK DF#2 Member Spacing @ 16"o.c. Maximum Moment = Check Deflection I (in^4) 20.80 Lumber Sp/Gr Actual Deflection (Live Load) = Allowed Deflection (Total Load) = Actual Deflection (Total Load) = Allowed > Actual -- 93.4% Stressed -- Therefore, OK Member Properties Member Size 2x6 S (in^3) 7.56 0.156 in Continuous Span 0.320 in Check Bending Stress (True Dimensions) Shea Residence, Carmel, IN 4