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Home My WebLink AboutLA224915-PE Calcs_CYNDI ENGLUND_Stamped-2024-06-01_20-00-465/31/2024 RE: Structural Certification for Installation of Residential Solar CYNDI ENGLUND:16252 EQUESTRIAN TRAIL, LAKEVILLE, MN 55044 Attn: To Whom It May Concern Design Criteria Code 2020 Minnesota Building Code (ASCE 7-16) Risk category II Wind Load (component and Cladding) Roof Dead Load Dr 10 psf V 115 mph PV Dead Load DPV 3 psf Exposure B Roof Live Load Lr 20 psf Ground Snow S 50 psf If you have any questions on the above, please do not hesitate to call. Sincerely, This Letter is for the existing roof framing which supports the new PV modules as well as the attachment of the PV system to existing roof framing. From the field observation report, the roof is made of Asphalt Shingle roofing over roof plywood supported by 2X4 Trusses at 24 inches. The slope of the roof was approximated to be 35 degrees. After review and based on our structural capacity calculation, the existing roof framing has been determined to be adequate to support the imposed loads without structural upgrades . Contractor shall verify that existing framing is consistent with the described above before install. Should they find any discrepancies, a written approval from SEOR is mandatory before proceeding with install. Capacity calculations were done in accordance with applicable building codes. 5/31/2024 Structural Letter for PV Installation Date:5/31/2024 Job Address:16252 EQUESTRIAN TRAIL LAKEVILLE, MN 55044 Job Name:CYNDI ENGLUND Job Number:053124CE Scope of Work Table of Content Sheet 1 Cover 2 Attachment checks 3 Snow and Roof Framing Check 4 Seismic Check and Scope of work Engineering Calculations Summary Code 2020 Minnesota Building Code (ASCE 7-16) Risk category II Roof Dead Load Dr 10 psf PV Dead Load DPV 3 psf Roof Live Load Lr 20 psf Ground Snow S 50 psf Wind Load (component and Cladding) V 115 mph Exposure B References 2 NDS for Wood Construction Sincerely, This Letter is for the existing roof framing which supports the new PV modules as well as the attachment of the PV system to existing roof framing. All PV mounting equipment shall be designed and installed per manufacturer's approved installation specifications. 5/31/2024 Wind Load Cont. 115 mph ASCE 7-16 Figure 26.5-1B B 1.0 ASCE 7-16 Sec 26.8.2 0.65 ASCE 7-16 Table 26.10-1 0.85 ASCE 7-16 Table 26.6-1 0.97 ASCE 7-16 Table 26.9-1 18.07 psf 35.0 Degrees 1.5 Conservatively assuming all exposed 0.8 conservatively assuming 10 ft2 effective area Uplift (W)Zone(1,2e,2r)Zone(2n)Zone(3r)Zone(3e) Fig. 30-3-2 GCp=-1.1 -1.1 -1.45 -1.8 Eq. 29.4-7 P=qh(GCp)(γE)(γa)=-23.85 -23.85 -31.44 -39.03 GCp=0.9 Figure 30.3-2 P=qh(GCp)(γE)(γa)=19.52 Equation 29.4-7 Rafter Attachments: 0.6D+0.6W (CD=1.6) Connection Check Attachement max. spacing=4 ft 5/16" Lag Screw Withdrawal Value=266 lbs/in Table 12.2A - NDS 2.5 in DFL Assumed Prying Coefficient 1.4 Allowable Capacity=760 lbs Zone Trib Width Area (ft)Uplift (lbs)Down (lbs) Zone(1,2e,2r)4 11.0 87.6 122.4 Zone(2n)4 11.0 87.6 122.4 Zone(3r)4 11.0 112.3 122.4 Zone(3e)4 11.0 137.1 122.4 Conservative Max=137.1 <760 CONNECTION IS OK Risk Category = KZ = Kd = Ke = 2. Embedment is measured from the top of the framing member to the tapered tip of a lag screw. Embedment in sheading or other material does not count. II Wind Speed (3s gust), V = Exposure = 1. Pv seismic dead weight is negligible to result in significant seismic uplift, therefore the wind uplift governs γE= γa= KZt = qh= 0.00256KzKztKdKeV2= Pitch = Lag Screw Penetration Vertical Load Resisting System Design Roof Framing Trusses Snow Load Fully Exposed pg=50 psf Ce =0.9 Ct =1.1 Is =1.0 pf = 35 psf pfmin. = 34.7 psf ps = 35 psf CS=0.5 36.96 plf Max Length, L =6.0 ft (Beam maximum Allowable Span) Tributary Width, WT =24 in Dr =10 psf 20 plf PvDL =3 psf 6 plf Load Case: DL+0.75(0.6W+S) 0.75(Pnet+Ps)+ Ppvcos(θ)+PDL=65 plf Mdown=181 lb-ft Mallowable = Sx x Fb' (wind)=634 lb-ft >181 lb-ft OK Load Case: DL+S Ps+ Ppvcos(θ)+PDL=62 plf Mdown=144 lb-ft Mallowable = Sx x Fb' (wind)=456 lb-ft >144 lb-ft OK Load Case: DL+0.6W Pnet+ Ppvcos(θ)+PDL=41.6 plf Max Moment, Mu=115 lb-ft Mallowable = Sx x Fb' (wind)=634 lb-ft >115 lb-ft OK Pv max Shear=122.4 lbs Shear, Vu=wL/2+Pv Point Load =200 lbs Max Shear, Vu=wL/2+Pv Point Load =200 lb Member Capacity DF-L No.2 2X4 CL CF Ci Cr KF φ λ Fb =900 psi 1.0 1.5 1.0 1.15 2.54 0.85 0.8 1553 psi Fv =180 psi N/A N/A 1.0 N/A 2.88 0.75 0.8 180 psi E =1600000 psi N/A N/A 1.0 N/A N/A N/A N/A 1600000 psi Emin =580000 psi N/A N/A 1.0 N/A 1.76 0.85 N/A 580000 psi Depth, d =3.5 in Width, b =1.5 in Cross-Sectonal Area, A =5.25 in2 Moment of Inertia, Ixx =5.35938 in4 Section Modulus, Sxx =3.0625 in3 Allowable Moment, Mall = Fb'Sxx =396.2 lb-ft DCR=Mu/Mall =0.32 < 1 Satisfactory Allowable Shear, Vall = 2/3Fv'A =630.0 lb DCR=Vu/Vall =0.21 < 1 Satisfactory Design Value Adjusted Value Siesmic Loads Check Roof Dead Load 10 psf % or Roof with Pv 22.0% Dpv and Racking 3 psf Average Total Dead Load 10.7 psf Increase in Dead Load 3.3%OK Limits of Scope of Work and Liability The increase in seismic Dead weight as a result of the solar system is less than 10% of the existing structure and therefore no further seismic analysis is required. We have based our structural capacity determination on information in pictures and a drawing set titled PV plans - CYNDI ENGLUND. The analysis was according to applicable building codes, professional engineering and design experience, opinions and judgments. The calculations produced for this Structure's assessment are only for the proposed solar panel installation referenced in the stamped plan set and were made according to generally recognized structural analysis standards and procedures.