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HomeMy WebLinkAboutKottam Engineering Letter___________________________________________________________________________________________ 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 KottamResidence 2481TownĞMeadowDr Carmel,IN.46032 ToWhomItMayConcern, DesignCriteria: භ ApplicableCodes=2014IndianaStateBuildingCode,ASCE7Ͳ10 භ RoofDeadLoad=7psf(MP1&2) භ RoofLiveLoad=20psf භ WindSpeed=115mph(Vult),ExposureC,RiskCategoryII භ භ Sincerely, JohnCalvert,P.E. ProjectEngineer Thescopeofthisreportisstrictlylimitedtoanevaluationofthefastenerattachment,underlyingframingandsupporting structureonly.Theattachment'stotheexistingstructurearerequiredtobeinastaggeredpatterntoensureproper distributionofloading.Allpanels,rackingandhardwareshallbeinstalledpermanufacturerspecificationsandwithinspecified designlimitations.Allwaterproofingshallbeprovidedbythemanufacturer.DomusStructuralEngineeringassumesno responsibilityformisuseorimproperinstallationofthesolarPVpanelsorracking. Pleasecontactmewithanyfurtherquestionsorconcernsregardingthisproject. Note:SeismiccheckisnotrequiredsinceSs<.4gandSeismicDesignCategory(SDC)<B Attachment:1Ͳ5/16dia.lagscrewwith2.5inchmin.embedment depth,atspacingshownabove. September7,2021 Theroofstructuresof(MP1&2)consistofcompositionshingleonroofplywoodthatissupportedbypreͲmanufacturedtrusses thatarespacedat@24"o.c..Thetopchords,slopedat45degrees,are2x4sections,thebottomchordsare2x4sectionsand thewebmembersare2x4sections.Thetrussmembersareconnectedbysteelgussetplates.Themaxunsupportedprojected horizontaltopchordspanisapproximately7'Ͳ0''. Theexistingroofframingsystemsof(MP1&2)arejudgedtobeadequatetowithstandtheloadingimposedbytheinstallation ofthesolarpanels.Noreinforcementisnecessary.Whereitisrequiredforstandoffs,installvertical2x6blockingbetweentruss topchords.AttachblocktoadjacenttrusseswithSimpsonA34clipsateachend.Seeattacheddetailforfurtherspecifications. GroundSnowLoad=20psfͲRoofSnowLoad=14psf Thespacingofthesolarstandoffsshouldbekeptat72"o.c.forlandscapeand48"o.c.forportraitorientation,withastaggered patterntoensureproperdistributionofloads. AjobsiteobservationoftheconditionoftheexistingframingsystemwasperformedbyanauditteamofBlueRavenSolarasa requestfromDomusStructuralEngineering.Allreviewisbasedontheseobservationsandthedesigncriterialistedbelowand onlydeemedvalidifprovidedinformationistrueandaccurate. Ontheabovereferencedproject,theroofstructuralframinghasbeenreviewedforadditionalloadingduetotheinstallationof thesolarPVadditiontotheroof.Thestructuralreviewonlyappliestothesectionoftheroofthatisdirectlysupportingthe solarPVsystemanditssupportingelements.Theobservedroofframingisdescribedbelow.Iffieldconditionsdiffer,contractor tonotifyengineerpriortostartingconstruction. Kottam Carmel IN.xlsm 1 9/9/2021 Digitally signed by John A. Calvert Date: 2021.09.09 15:05:16 -06'00' 9/9/2021 ____________________________________________________________________________________ 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 6.08 ft 24.33 sft 73 lb 4.00 2.00 0.73 0.00 (Ceiling Not Vaulted) 0.27 7.0 psf 9.9 psf PV Dead Load = 3 psf (Per Blue Raven Solar) DL Adjusted to 45 Degree Slope Point Loads of Standoffs Miscellaneous Vaulted Ceiling Total Roof DL (MP1&2) Roof Live Load = 20 psf Roof Plywood Roof Dead Load (MP1&2) Composition Shingle Note: Roof live load is removed in area's covered by PV array. Roof Snow Load Calculations pg = Ground Snow Load = Ce = Exposure Factor = pf = 0.7 Ce Ct I pg Ct = Thermal Factor = 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 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. Kottam Carmel IN.xlsm 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 21.3 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 = -0.94 -1.15 -1.15 0.86 (Fig. 30.4-1) Uplift Pressure = -14.55 psf -17.80 psf -17.80 psf 22.4 psf X Standoff Spacing = 4.00 4.00 2.67 Y Standoff Spacing = 6.08 3.041666667 3.04166667 Tributary Area = 24.33 12.17 8.11 Dead Load on Attachment= 73.00 36.50 24.33 Footing Uplift (0.6D+0.6W)= -310 lb -195 lb -130 lb Zone 1 Zone 2 Zone 3 Positive GCp = -0.94 -1.15 -1.15 0.86 (Fig. 30.4-1) Uplift Pressure = -14.55 psf -17.80 psf -17.80 psf 10.5 psf X Standoff Spacing = 6.00 6.00 4.00 Y Standoff Spacing = 3.50 1.75 1.75 Tributary Area = 21.00 10.50 7.00 Dead Load on Attachment= 63.00 31.50 21.00 Footing Uplift (0.6D+0.6W) = -268 lb -168 lb -112 lb -310 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 Input Variables Wind Speed Effective Wind Area Design Wind Pressure Calculations Roof Shape Standoff Uplift Calculations-Portrait Mean Roof Height Roof Slope 667.2 lb capacity > 310 lb demand 0.6 * qh = Standoff Uplift Calculations-Landscape Wind Calculations Maximum Design Uplift = Standoff Uplift Capacity = 450 lb capacity > 310 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 PerASCE7Ͳ10ComponentsandCladding Kottam Carmel IN.xlsm 3 ___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 6986 Broomfield, CO 80021 530-864-7055 Domusstructural@gmail.com (MP1&2)PASS Dead Load 9.9 psf PV Load 4.2 psf Snow Load 14.0 psf Governing Load Combo = DL + LL Total Load 34.1 psf Fb (psi) = f'b x Cd x Cf x Cr (NDS Table 4.3.1) 900 x 1.25 x 1.5 x 1.15 Allowed Bending Stress = 1940.6 psi (wL^2) / 8 = 418.2412 ft# = 5018.894 in# Actual Bending Stress = (Maximum Moment) / S = 1638.9 psi L/180 (E = 1600000 psi Per NDS) = 0.466 in Deflection Criteria Based on = (w*L^4) / (185*E*I) = = L/470 > L/180 Therefore OK Allowed Deflection (Live Load) =L/240 0.35 in (w*L^4) / (185*E*I) L/800 > L/240 Therefore OK Member Area = Fv (psi) = 180 psi (NDS Table 4A) Allowed Shear = Fv * A = Max Shear (V) = w * L / 2 = 239 lb Check Bending Stress (True Dimensions) Continuous Span 0.179 in 0.105 in Member Properties Member Size 2x4 S (in^3) 3.06 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 -- 84.5% Stressed -- Therefore, OK 945 lb Allowed > Actual -- 25.3% Stressed -- Therefore, OK 5.3 in^2 Check Shear w = 68 plf 2x4 Top Chords @ 24"o.c. Member Span = 7' - 0" Framing Check Kottam Carmel IN.xlsm 4