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Home My WebLink AboutPE Calcs_JEFFREY CUTTER_stampedprojects@evengineersnet.com http://www.evengineersnet.com 276-220-0064 5/11/2022 RE: Structural Certification for Installation of Residential Solar JEFFREY CUTTER:33 PRINCE RD, YARMOUTH, MA, 02601 Attn: To Whom It May Concern Design Criteria Code 2015 IRC (ASCE 7-10)-CMR 780 9th Ed Risk category II Wind Load (component and Cladding) Roof Dead Load Dr 10 psf V 140 mph PV Dead Load DPV 3 psf Exposure C Roof Live Load Lr 20 psf Ground Snow S 30 psf If you have any questions on the above, please do not hesitate to call. Sincerely, Vincent Mwumvaneza, P.E. EV Engineering, LLC projects@evengineersnet.com http://www.evengineersnet.com 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 Composite shingle roofing over roof plywood supported by 1X8 Rafters at 16 inches. The slope of the roof was approximated to be 18, 19, and 40 degrees. After review of the field observation data 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. 1/1 projects@evengineersnet.com http://www.evengineersnet.com 276-220-0064 Structural Letter for PV Installation 5/11/2022 Job Address:33 PRINCE RD YARMOUTH, MA, 02601 Job Name:JEFFREY CUTTER Job Number:220511JC Scope of Work Table of Content Sheet 1 Cover2Attachment checks3Snow and Roof Framing Check 4 Seismic Check and Scope of work Engineering Calculations Summary Code 2015 IRC (ASCE 7-10)-CMR 780 9th Ed Risk category II Roof Dead Load Dr 10 psf PV Dead Load DPV 3 psf Roof Live Load Lr 20 psf Ground Snow S 30 psf Wind Load (component and Cladding) V 140 mph Exposure C References NDS for Wood Construction Sincerely, Vincent Mwumvaneza, P.E. EV Engineering, LLC projects@evengineersnet.com http://www.evengineersnet.com 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. 1/1 projects@evengineersnet.com http://www.evengineersnet.com 276-220-0064 Wind Load Cont. ASCE 7-10 Table 1.5-1 140 mph ASCE 7-10 Figure 26.5-1A ASCE 7-10 Sec 26.7.2 ASCE 7-10 Sec 26.7.3 ASCE 7-10 Sec 26.8.2 40.0 Degrees ASCE 7-10 Figure 30.5-1 6.00 ft ASCE 7-10 Figure 30.5-1 Uplift (0.6W)Zone 1 (psf)Zone 2 (psf)Zone 3 (psf) Pnet30=-29.3 -35.3 -35.3 Figure 30.5-1 Pnet = 0.6 x λ x KZT x Pnet30)=23.75 28.60 28.60 Equation 30.5-1 Downpressure (0.6W)Zone 1 (psf)Zone 2 (psf)Zone 3 (psf) Pnet30=32.1 32.1 32.1 Figure 30.5-1 Pnet = 0.6 x λ x KZT x Pnet30)=25.98 25.98 25.98 Equation 30.5-1 Rafter Attachments: 0.6D+0.6W (CD=1.6) Connection Check Attachment max. spacing=5.3 ft 5/16" Lag Screw Withdrawal Value=205 lbs/in 2.5 in Allowable Capacity=512.5 0.6D+0.6W Dpv+0.6W Zone Trib Width Area (ft)Uplift (lbs)Down (lbs) 1 5.3 11.1 244.3 322.5 2 5.3 11.1 298.3 322.5 3 3 6.3 168.9 182.6 Max=298.3 <512.5 CONNECTION IS OK 1. Pv seismic dead weight is negligible to result in significant seismic uplift, therefore the wind uplift governs 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. Topographic Factor, KZT =1.00 Pitch = Adjustment Factor, λ =1.35 a = Where a: 10% of least horizontal dimension or 0.4h, whichever is smaller, but not less than 4% of least horizontal dimension or 3ft (0.9m) Lag Screw Penetration Exposure =C Risk Category =II Wind Speed (3s gust), V = Roughness =C 1/1 projects@evengineersnet.com http://www.evengineersnet.com 276-220-0064 Vertical Load Resisting System Design Roof Framing Rafters Pg=30 psf ASCE 7-10 , Section 7.2 pf = 21 psf Ce=0.9 ASCE 7-10 , Table 7-2 pfmin. = 30.0 psf Ct =1.1 ASCE 7-10 , Table 7-3 ps = 30 psf 20.0 plf Is =1.0 ASCE 7-10 , Table 1.5-1 CS 0.5 Max Length, L =13.1 ft Tributary Width, WT =16 in Dr =10 psf 13.33 plf PvDL =3 psf 4 plf Load Case: DL+0.6W Pnet+ Ppvcos(θ)+PDL=52.0 plf Max Moment, Mu =652 lb-ft Conservatively Pv max Shear 322.5 lbs Max Shear, Vu=wL/2+Pv Point Load =436 lbs Load Case: DL+0.75(0.6W+S)) 0.75(Pnet+Ps)+ Ppvcos(θ)+PDL=57 plf Mdown=720 lb-ft Mallowable = Sx x Fb' (wind)=1410 lb-ft >720 lb-ft OK Load Case: DL+S Ps+ Ppvcos(θ)+PDL=36 plf Mdown=457 lb-ft Mallowable = Sx x Fb' (wind)=1014 lb-ft >457 lb-ft OK Max Shear, Vu=wL/2+Pv Point Load =436 lbs Member Capacity SPF #1/#2 1X8 CL CF Ci Cr Fb =875 psi 1.0 1.2 1.0 1.15 1208 psi Fv =135 psi N/A N/A 1.0 N/A 135 psi E =1400000 psi N/A N/A 1.0 N/A 1400000 psi Depth, d =7.25 in Width, b =1 in Cross-Sectonal Area, A =7.25 in2 Moment of Inertia, Ixx =31.7565 in4 Section Modulus, Sxx =8.76042 in3 Allowable Moment, Mall = Fb'Sxx =881.5 lb-ft DCR=Mu/Mall =0.51 < 1 Satisfactory Allowable Shear, Vall = 2/3Fv'A =652.5 lb DCR=Vu/Vall =0.67 < 1 Satisfactory Design Value Adjusted Value 1/1 projects@evengineersnet.com http://www.evengineersnet.com 276-220-0064 Siesmic Loads Check Roof Dead Load 10 psf % or Roof with Pv 35% Dpv and Racking 3 psf Averarage Total Dead Load 11.1 psf Increase in Dead Load 4.2%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 -JEFFREY CUTTER. 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. 1/1