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HomeMy WebLinkAboutLA208265-APPROVED - Chhoun Engineering Letter Flat___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 6986 Broomfield, CO 80021 530-864-7055 Domusstructural@gmail.com To: BlueRavenSolar 1403NorthResearchWay,BuildingJ Orem,UT.84097 Subject: CertificationLetter ChhounResidence 19977HarrisburgWay Lakeville,MN.55044 ToWhomItMayConcern, DesignCriteria: භ ApplicableCodes=2018IBC/IRC,ASCE7Ͳ16 භ RoofDeadLoad=7psf(MP1) භ RoofLiveLoad=20psf භ WindSpeed=115mph(Vult),ExposureC භ භ Sincerely, JohnCalvert,P.E. ProjectEngineer November8,2022 Theroofstructureof(MP1)consistsofcompositionshingleonroofplywoodthatissupportedbypreͲmanufacturedtrussesthat arespacedat@24"o.c..Thetopchords,slopedat34degrees,are2x4sections,thebottomchordsare2x4sectionsandtheweb membersare2x4sections.Thetrussmembersareconnectedbysteelgussetplates.Themaxunsupportedprojectedhorizontal topchordspanisapproximately6'Ͳ8''. Theexistingroofframingsystemof(MP1)isjudgedtobeadequatetowithstandtheloadingimposedbytheinstallationofthe solarpanels.Noreinforcementisnecessary. GroundSnowLoad=50psfͲRoofSnowLoad=35psf Thespacingofthesolarstandoffsshouldbekeptat48"o.c.forlandscapeand24"o.c.forportraitorientation,withastaggered patterntoensureproperdistributionofloads. AjobsiteobservationoftheconditionoftheexistingframingsystemwasperformedbyanauditteamofBlueRavenSolarasa requestfromDomusStructuralEngineering.Allreviewisbasedontheseobservationsandthedesigncriterialistedbelowand onlydeemedvalidifprovidedinformationistrueandaccurate. Ontheabovereferencedproject,theroofstructuralframinghasbeenreviewedforadditionalloadingduetotheinstallationof thesolarPVadditiontotheroof.Thestructuralreviewonlyappliestothesectionoftheroofthatisdirectlysupportingthesolar PVsystemanditssupportingelements.Theobservedroofframingisdescribedbelow.Iffieldconditionsdiffer,contractorto notifyengineerpriortostartingconstruction. Thescopeofthisreportisstrictlylimitedtoanevaluationofthefastenerattachment,underlyingframingandsupporting structureonly.Theattachment'stotheexistingstructurearerequiredtobeinastaggeredpatterntoensureproperdistribution ofloading.Allpanels,rackingandhardwareshallbeinstalledpermanufacturerspecificationsandwithinspecifieddesign limitations.Allwaterproofingshallbeprovidedbythemanufacturer.DomusStructuralEngineeringassumesnoresponsibility formisuseorimproperinstallationofthesolarPVpanelsorracking. Pleasecontactmewithanyfurtherquestionsorconcernsregardingthisproject. Note:SeismiccheckisnotrequiredsinceSs<.4gandSeismicDesignCategory(SDC)<B Attachment:1Ͳ5/16dia.lagscrewwith2.5inchmin.embedment depth,atspacingshownabove. Chhoun Lakeville MN.xlsm 1 I hereby certify that this plan, specification or report was prepared byme or under my direct supervision and that I am a duly LicensedProfessional Engineer under the laws of the State of Minnesota.John A.Calvert, License No. 52823 Expiration Date: 30-June-2024 Digitally signed by John A. Calvert Date: 2022.11.09 10:34:23 -07'00' Concept Approval ONLYSubject to Field Inspection Inspector Date 2020 MN Bldg Code 11/14/2022dpfannenstein Provide copy of city approved plans on the job site for the inspector ____________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 6986 Broomfield, CO 80021 530-864-7055 Domusstructural@gmail.com 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 3.62 psf 3.0 psf 2.00 ft 6.08 ft 12.17 sft 37 lb 4.00 2.00 0.73 0.00 (Ceiling Not Vaulted) 0.27 7.0 psf 8.4 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 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 = DL Adjusted to 34 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 34 Degree Slope Point Loads of Standoffs Miscellaneous Vaulted Ceiling Total Roof DL (MP1) PV Dead Load = 3 psf (Per Blue Raven Solar) Chhoun Lakeville MN.xlsm 2 ___________________________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 6986 Broomfield, CO 80021 530-864-7055 Domusstructural@gmail.com 115 mph C Gable Roof 34 degrees 20 ft 21.3 ft 0 ft (Eq. 26.10-1) 0.90 (Table 30.3-1) 1.00 (Fig. 26.8-1) 0.85 (Table 26.6-1) 1.00 115 mph (Fig. 26.5-1A) II (Table 1.5-1) qh = 25.95 Zone 1 Zone 2 Zone 3 Positive ya =0.77 0.80 0.80 0.77 GCp =-1.71 -2.00 -2.89 0.87 (Fig. 30.3) Uplift Pressure =-34.3 psf -41.5 psf -60.0 psf 17.3 psf (Eq. 29.4-7) ASD Uplift Pressure =-20.6 psf -24.9 psf -36.0 psf 10.4 psf X Standoff Spacing = 2.00 2.00 1.33 Y Standoff Spacing = 6.08 3.04166667 3.04166667 Tributary Area = 12.17 6.08 4.06 Dead Load on attachment = 37 lb 18 lb 12 lb Footing Uplift (0.6D+0.6W) = -229 lb -141 lb -139 lb Zone 1 Zone 2 Zone 3 Positive ya =0.75 0.80 0.80 0.75 GCp =-1.65 -2.00 -2.83 0.84 (Fig. 30.3) Uplift Pressure =-32.2 psf -41.5 psf -58.7 psf 16.4 psf (Eq. 29.4-7) ASD Uplift Pressure (0.6W)=-19.3 psf -24.9 psf -35.2 psf 9.8 psf X Standoff Spacing = 4.00 4.00 2.67 Y Standoff Spacing = 3.50 1.75 1.75 Tributary Area = 14.00 7.00 4.67 Dead Load on attachment = 42.00 21.00 14.00 Footing Uplift (0.6D+0.6W) = -246 lb -162 lb -156 lb -246 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 Fastener Capacity Check Mean Roof Height Ground Elevation Kd (Wind Directionality Factor) = 667.2 lb capacity > 246 lb demand Ke (Ground Elevation Factor) = V (Design Wind Speed) = Risk Category = Standoff Uplift Calculations-Portrait Standoff Uplift Calculations-Landscape Standoff Uplift Check Standoff Uplift Capacity = 450 lb capacity > 246 lb demand Wind Calculations Maximum Design Uplift = Design Wind Pressure Calculations qh = 0.00256 * Kz * Kzt * Kd * Ke * V^2 Kz (Exposure Coefficient) = Kzt (topographic factor) = Wind Speed Exposure Category Roof Shape Roof Slope Effective Wind Area PerASCE7Ͳ16ComponentsandCladding Input Variables Chhoun Lakeville MN.xlsm 3 ___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 6986 Broomfield, CO 80021 530-864-7055 Domusstructural@gmail.com (MP1)PASS Dead Load 8.4 psf PV Load 3.6 psf Snow Load 35.0 psf Governing Load Combo = DL + SL Total Load 47.1 psf Fb (psi) = f'b x Cd x Cf x Cr (NDS Table 4.3.1) 1650 x 1.15 x 1 x 1.15 Allowed Bending Stress = 2182.1 psi (wL^2) / 8 = 522.9131 ft# = 6274.957 in# Actual Bending Stress = (Maximum Moment) / S = 2049 psi L/180 (E = 1500000 psi Per NDS) = 0.444 in Deflection Criteria Based on = (w*L^4) / (185*E*I) = = L/369 > L/180 Therefore OK Allowed Deflection (Live Load) =L/240 0.333 in (w*L^4) / (185*E*I) L/497 > L/240 Therefore OK Member Area = Fv (psi) = 135 psi (NDS Table 4A) Allowed Shear = Fv * A = Max Shear (V) = w * L / 2 = 314 lb Framing Check 5.3 in^2 Check Shear w = 94 plf 2x4 Top Chords @ 24"o.c. Member Span = 6' - 8" 709 lb Allowed > Actual -- 44.3% Stressed -- Therefore, OK 1650Fb/1.5E 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 -- 94% Stressed -- Therefore, OK Member Properties Member Size 2x4 S (in^3) 3.06 0.161 in Continuous Span 0.217 in Check Bending Stress (True Dimensions) Chhoun Lakeville MN.xlsm 4