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HomeMy WebLinkAboutLA208675-APPROVED - Valluru 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 ValluruResidence 7680205thStW 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 November7,2022 Theroofstructureof(MP1)consistsofcompositionshingleonroofplywoodthatissupportedbypreͲmanufacturedtrussesthat arespacedat@24"o.c..Thetopchords,slopedat26degrees,are2x4sections,thebottomchordsare2x4sectionsandtheweb membersare2x4sections.Thetrussmembersareconnectedbysteelgussetplates.Themaxunsupportedprojectedhorizontaltop chordspanisapproximately6'Ͳ0''. Theexistingroofframingsystemof(MP1)isjudgedtobeadequatetowithstandtheloadingimposedbytheinstallationofthe solarpanels.Noreinforcementisnecessary. GroundSnowLoad=50psfͲRoofSnowLoad=35psf Thespacingofthesolarstandoffsshouldbekeptat48"o.c.forlandscapeand24"o.c.forportraitorientation,withastaggered patterntoensureproperdistributionofloads. AjobsiteobservationoftheconditionoftheexistingframingsystemwasperformedbyanauditteamofBlueRavenSolarasa requestfromDomusStructuralEngineering.Allreviewisbasedontheseobservationsandthedesigncriterialistedbelowandonly deemedvalidifprovidedinformationistrueandaccurate. Ontheabovereferencedproject,theroofstructuralframinghasbeenreviewedforadditionalloadingduetotheinstallationofthe solarPVadditiontotheroof.ThestructuralreviewonlyappliestothesectionoftheroofthatisdirectlysupportingthesolarPV systemanditssupportingelements.Theobservedroofframingisdescribedbelow.Iffieldconditionsdiffer,contractortonotify engineerpriortostartingconstruction. Thescopeofthisreportisstrictlylimitedtoanevaluationofthefastenerattachment,underlyingframingandsupportingstructure only.Theattachment'stotheexistingstructurearerequiredtobeinastaggeredpatterntoensureproperdistributionofloading. Allpanels,rackingandhardwareshallbeinstalledpermanufacturerspecificationsandwithinspecifieddesignlimitations.All waterproofingshallbeprovidedbythemanufacturer.DomusStructuralEngineeringassumesnoresponsibilityformisuseor improperinstallationofthesolarPVpanelsorracking. Pleasecontactmewithanyfurtherquestionsorconcernsregardingthisproject. Note:SeismiccheckisnotrequiredsinceSs<.4gandSeismicDesignCategory(SDC)<B Attachment:1Ͳ5/16dia.lagscrewwith2.5inchmin.embedment depth,atspacingshownabove. Valluru Lakeville MN 1 I hereby certify that this plan, specification or report was prepared by me orunder my direct supervision and that I am a duly Licensed ProfessionalEngineer under the laws of the State of Minnesota.John A. Calvert, LicenseNo. 52823 Expiration Date: 30-June-2024 Digitally signed by John A. Calvert Date: 2022.11.08 16:15:10 -07'00' Concept Approval ONLYSubject to Field Inspection Inspector Date 2020 MN Bldg Code 12/06/2022dpfannenstein 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 3.34 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 7.8 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 26 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 areas 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) Valluru Lakeville MN 2 ___________________________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 6986 Broomfield, CO 80021 530-864-7055 Domusstructural@gmail.com 115 mph C Gable Roof 26 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 =-1.50 -2.50 -3.59 0.52 (Fig. 30.3) Uplift Pressure =-30.0 psf -51.9 psf -74.5 psf 10.3 psf (Eq. 29.4-7) ASD Uplift Pressure =-18.0 psf -31.1 psf -44.7 psf 9.6 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) = -197 lb -179 lb -174 lb Zone 1 Zone 2 Zone 3 Positive ya =0.75 0.80 0.80 0.75 GCp =-1.50 -2.50 -3.49 0.50 (Fig. 30.3) Uplift Pressure =-29.2 psf -51.9 psf -72.5 psf 9.8 psf (Eq. 29.4-7) ASD Uplift Pressure (0.6W)=-17.5 psf -31.1 psf -43.5 psf 9.6 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) = -220 lb -205 lb -195 lb -220 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 > 220 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 > 220 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 Valluru Lakeville MN 3 ___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 6986 Broomfield, CO 80021 530-864-7055 Domusstructural@gmail.com (MP1)PASS Dead Load 7.8 psf PV Load 3.3 psf Snow Load 35.0 psf Governing Load Combo = DL + SL Total Load 46.1 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 = 415.134 ft# = 4981.61 in# Actual Bending Stress = (Maximum Moment) / S = 1626.7 psi L/180 (E = 1600000 psi Per NDS) = 0.4 in Deflection Criteria Based on = (w*L^4) / (185*E*I) = = L/550 > 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 =277 lb Framing Check 5.3 in^2 Check Shear w = 92 plf 2x4 Top Chords @ 24"o.c. Member Span = 6' - 0" 945 lb Allowed > Actual -- 29.3% 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 -- 91.2% Stressed -- Therefore, OK Member Properties Member Size 2x4 S (in^3) 3.06 0.099 in Continuous Span 0.131 in (True Dimensions) Check Bending Stress Valluru Lakeville MN 4