The URL can be used to link to this page

Home My WebLink AboutENGINEER LETTER - 23-00873 - 6509 E 2000 N - Solar Panels___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 560 Broomfield, CO 80038 530-864-7055 projects@domusstruc.com To: BlueRavenSolar 1403NorthResearchWay,BuildingJ Orem,UT.84097 Subject: CertificationLetter BakerResidence 6509East2000N SugarCity,ID.83448 ToWhomItMayConcern, DesignCriteria: භ ApplicableCodes=2015IBC/IRC,ASCE7Ͳ10 භ RoofDeadLoad=4psf(MP1) භ RoofLiveLoad=20psf භ WindSpeed=115mph(Vult),ExposureC,RiskCategoryII භ භ Sincerely, BrandonLittle,P.E. ProjectEngineer Thescopeofthisreportisstrictlylimitedtoanevaluationofthefastenerattachment,underlyingframingandsupporting structureonly.Theattachmentstotheexistingstructurearerequiredtobeinastaggeredpatterntoensureproperdistribution ofloading.Allpanels,rackingandhardwareshallbeinstalledpermanufacturerspecificationsandwithinspecifieddesign limitations.Allwaterproofingshallbeprovidedbythemanufacturer.DomusStructuralEngineeringassumesnoresponsibility formisuseorimproperinstallationofthesolarPVpanelsorracking. Pleasecontactmewithanyfurtherquestionsorconcernsregardingthisproject. Attachment:SͲ5!Solarfootw/(4)1/4x11/2"fastenersintothe wooddecking,atspacingshownabove. November16,2023 Theroofstructureof(MP1)consistsofmetalroofingonroofplywoodthatissupportedbypreͲmanufacturedtrussesthatare spacedat@24"o.c..Thetopchords,slopedat20degrees,are2x4sections,thebottomchordsare2x4sectionsandtheweb membersare2x4sections.Thetrussmembersareconnectedbysteelgussetplates.Themaxunsupportedprojectedhorizontal topchordspanisapproximately6'Ͳ6''. Theexistingroofframingsystemof(MP1)isjudgedtobeadequatetowithstandtheloadingimposedbytheinstallationofthe solarpanels.Noreinforcementisnecessary. GroundSnowLoad=50psfͲRoofSnowLoad=35psf Thespacingofthesolarstandoffsshouldbekeptat32"o.c.forlandscapeand24"o.c.forportraitorientation,withastaggered patterntoensureproperdistributionofloads. AjobsiteobservationoftheconditionoftheexistingframingsystemwasperformedbyanauditteamofBlueRavenSolarasa requestfromDomusStructuralEngineering.Allreviewisbasedontheseobservationsandthedesigncriterialistedbelowand onlydeemedvalidifprovidedinformationistrueandaccurate. Ontheabovereferencedproject,theroofstructuralframinghasbeenreviewedforadditionalloadingduetotheinstallationof thesolarPVadditiontotheroof.Thestructuralreviewonlyappliestothesectionoftheroofthatisdirectlysupportingthesolar PVsystemanditssupportingelements.Theobservedroofframingisdescribedbelow.Iffieldconditionsdiffer,contractorto notifyengineerpriortostartingconstruction. Baker Sugar City ID 1 Brando n R. Little Digitally signed by Brandon R. Little Date: 2023.11.16 15:54:15 -07'00' ___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 560 Broomfield, CO 80038 530-864-7055 projects@domusstruc.com 50.0 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 3.19 psf 3.0 psf 2.00 ft 3.08 ft 6.17 sft 19 lb 1.00 2.00 0.73 0.00 (Ceiling Not Vaulted) 0.27 4.0 psf 4.3 psf PV Dead Load = 3 psf (Per Blue Raven Solar) DL Adjusted to 20 Degree Slope Point Loads of Standoffs Miscellaneous Vaulted Ceiling Total Roof DL (MP1) Roof Live Load = 20 psf Roof Plywood Roof Dead Load (MP1) Metal Roofing 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 20 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. Baker Sugar City ID 2 ___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 560 Broomfield, CO 80038 530-864-7055 projects@domusstruc.com 115 mph C Hip/Gable 20 degrees 20 ft 21.2 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 = -0.85 -1.52 -2.42 0.43 (Fig. 30.4-1) Uplift Pressure = -13.20 psf -23.68 psf -37.60 psf 11.1 psf X Standoff Spacing = 2.00 2.00 1.33 Y Standoff Spacing = 3.08 3.083333333 3.08333333 Tributary Area = 6.17 6.17 4.11 Dead Load on Attachment=18.50 18.50 12.33 Footing Uplift (0.6D+0.6W)= -70 lb -135 lb -147 lb Zone 1 Zone 2 Zone 3 Positive GCp = -0.85 -1.52 -2.42 0.43 (Fig. 30.4-1) Uplift Pressure = -13.20 psf -23.68 psf -37.60 psf 10.0 psf (Minimum) X Standoff Spacing = 2.67 2.67 1.78 Y Standoff Spacing = 1.71 1.7125 1.7125 Tributary Area = 4.57 4.57 3.04 Dead Load on Attachment=13.70 13.70 9.13 Footing Uplift (0.6D+0.6W) = -52 lb -100 lb -109 lb -147 lb 178 lb Therefore, OK Fastener =4 - 1/4 x 1 1/2" Number of Fasteners = 4 Embedment Depth = 0.5 Pullout Capacity Per Screw = 177 lb Fastener Capacity = 708 lb w/ F.S. of 3= 236 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 236 lb capacity > 147 lb demand 0.6 * qh = Standoff Uplift Calculations-Landscape Wind Calculations Maximum Design Uplift = Standoff Uplift Capacity = 178 lb capacity > 147 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 Baker Sugar City ID 3 ___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 560 Broomfield, CO 80038 530-864-7055 projects@domusstruc.com (MP1)PASS Dead Load 4.3 psf PV Load 3.2 psf Snow Load 35.0 psf Governing Load Combo = DL + SL Total Load 42.4 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 = 448.3701 ft# = 5380.442 in# Actual Bending Stress = (Maximum Moment) / S = 1756.9 psi L/180 (E = 1600000 psi Per NDS) = 0.433 in Deflection Criteria Based on = (w*L^4) / (185*E*I) = = L/470 > L/180 Therefore OK Allowed Deflection (Live Load) =L/240 0.325 in (w*L^4) / (185*E*I) L/570 > L/240 Therefore OK Member Area = Fv (psi) = 180 psi (NDS Table 4A) Allowed Shear = Fv * A = Max Shear (V) = w * L / 2 = 276 lb Check Bending Stress (True Dimensions) Continuous Span 0.166 in 0.137 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 -- 98.5% Stressed -- Therefore, OK 945 lb Allowed > Actual -- 29.2% Stressed -- Therefore, OK 5.3 in^2 Check Shear w = 85 plf 2x4 Top Chords @ 24"o.c. Member Span = 6' - 6" Framing Check Baker Sugar City ID 4 ___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 560 Broomfield, CO 80038 530-864-7055 projects@domusstruc.com Level Area Weight (psf) Weight (lb) Roof 4542 sf 4.3 psf 19333 lb Ceiling 4542 sf 6.0 psf 27251 lb Wood Siding 100 ft 5.0 psf 2000 lb (8'-0" Wall Height) Int. Walls 100 ft 6.4 psf 2560 lb 51144 lb 3.0 psf 507 sf 1521 lb 5114 lb 1521 lb 3.0% Lateral Check 5114 lb > 1521 lb, Therefore OK Existing Weight of Effected Building Existing Weight of Effected Building Proposed Weight of PV System Weight of PV System (Per Blue Raven Solar) 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 Baker Sugar City ID 5 ___________________________________________________________________________________________ Domus Structural Engineering, LLC P.O. Box 560 Broomfield, CO 80038 530-864-7055 projects@domusstruc.com Appendix A: General Notes GENERAL Ɣ The contractor shall verify all dimensions, property setbacks, AHJ/HOA CC&R's, elevations and site conditions before starting work and shall notify Domus Structural Engineering, LLC of any discrepancies. Ɣ All report conclusions represent Domus Structural Engineering, LLC's best professional judgment based upon industry standards. Ɣ Resolve any conflicts on the drawings with Domus Structural Engineering, LLC before proceeding with construction. Ɣ The design criteria used for this project & listed on the first page of the report is based on the engineers best judgement and/or provided by the ATC council. AHJ specific requests may differ. Please contact our team if the design criteria needs to be modified. Ɣ A site visit was not physically conducted by Domus Structural Engineering, LLC. The accompanying calculations and certification are provided with the understanding that the site building and construction standards meet an acceptable level of industry standards. It shall be the contractors responsibility to identify any irregularities such as inconsistent framing conditions, water damage, fire damage, cracked, split or noticeably deflecting framing members. Ɣ Domus Structural Engineering, LLC is not responsible for enforcing safety measures or regulations. The contractor shall design, construct, and maintain all safety devices including shoring and bracing, and shall be solely responsible for conforming to all local, state and federal safety and health standards, laws and regulations. The contractor shall take necessary precautions to maintain and insure the integrity of the structure during construction. If a lawsuit is filed by one of the contractor's or subcontractor's employees, or any one else, the contractor will indemnify, defend and hold the owner and Domus Structural Engineering, LLC harmless of any and all such claims. Ɣ Any and all waterproofing shall be provided by the contractor. Domus Structural Engineering, LLC is not responsible for waterproofing. Ɣ All hardware shall be installed per manufacturer specifications and within specified design limitations. Domus Structural Engineering, LLC assumes no responsibility for incorrectly installed hardware or hardware installed outside of the manfacturer specifications. USER RELIANCE Ɣ Domus Structural Engineering, LLC was engaged by Blue Raven Solar (Client) to perform this assessment. This report and the information therein, are for the exclusive use of the Client. This report has no other purpose and shall not be relied upon, or used, by any other person or entity without the written consent of Dous Structural Engineering, LLC. Third parties that obtain this report, or the information within shall have no rights of recourse or recovery against Domus Structural Engineering, LLC, it’s officers or employees. ROOF MOUNTED ARRAYS Ɣ If an analysis of a supporting stucture is included in our scope of work, the structural assessment only applies to the section of the roof that is directly supporting the proposed solar PV system. Ɣ No structural members can be cut for conduit, etc., unless specifically shown. Obtain prior written approval for installation of any additional conduit, etc. Ɣ It is assumed that a standard quality of construction care was used to construct the original building. It shall be the contractors responsibility to field verify any and all framing member supporting the proposed PV array are in adequate condition. The contractor shall field inspect for sub-standard construction means, signs of dry rot, mold, fire damage, etc. and notify engineer if any compromised material is found on site prior to starting construction. Ɣ It is assumed that there have been no additional loads (HVAC or MEP equipment, additional layers of roofing, etc) added to the building over the course of the structures histroy. The contractor and/or client shall verify this with the property owner and notify Domus Structural Engineering, LLC if additional load has been added to the structure already. Ɣ Flexible utility connections must be used at any building seismic joint. Ɣ Care should be taken to ensure that PV arrays do not preclude drainage of rain water. Ɣ Unless otherwise noted, construction material shall be evenly distributed if placed on framed floors or roofs. Loads shall not exceed the allowable loading for the supporting members and their connections. Ɣ All lags or wood screws at the roof shall be stainless steel and installed withing the middle 1/3 of the dimensional width of the framing members. Ɣ All fasteners shall be a minimum of 6" away from any truss panel or hinge joints, truss plates and/or member ends. Field verify location of fasteners prior to starting construction. All fasteners shall be pre-drilled to avoid splitting existing lumber. Ɣ Domus Structural Engineering, LLC is not responsible for downslope effects of snow shedding or sliding off of the PV array nor any damage to downslope decks, roofs, walkways, landscaping, automobiles, pets, people, etc.. If snow guards are requested by the customer, notify Domus Structural Engineering, LLC. Baker Sugar City ID 6