The URL can be used to link to this page

Home My WebLink AboutAPPROVED, Widman Residence - Stamped Engineering Calculations - Rev1(1)10/18/2021 RE: Structural Certification for Installation of Residential Solar WIDMAN RUDOLPH:421 SE TRANQUILLA AVE, PORT ST. LUCIE, FL 34983 Attn: To Whom It May Concern Code 2020 Florida Building Code (ASCE 7‐16) Risk category II Wind Load (component and Cladding) Roof Dead Load Dr 10 psf V 160 mph PV Dead Load DPV 3 psf Exposure B Roof Live Load Lr 20 psf Ground Snow S 0 psf If you have any questions on the above, please do not hesitate to call. Sincerely, Vincent Mwumvaneza, P.E EV Engineering LLC 276‐220‐0064/951‐355‐3348 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 1/2 inch plywood supported by 2X4 Trusses at 24 inches .The slope of the roof was approximated to be 18 degrees and having an allowable maximum chord span of 6 feet between supports. 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. projects@evengineersnet.com http://www.evengineersnet.com Structural Letter for PV Installation Date: 10/18/2021 Job Address:421 SE TRANQUILLA AVE PORT ST. LUCIE, FL 34983 Job Name:WIDMAN RUDOLPH Job Number:211001WR Scope of Work Table of Content Sheet 1 Cover 2 Attachment checks 3 Roof Framing Check 4 Seismic Check and Scope of work Engineering Calculations Summary Code 2020 Florida 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 0 psf Wind Load (component and Cladding) V 160 mph Exposure B References NDS for Wood Construction Sincerely, Vincent Mwumvaneza, P.E EV Engineering LLC 276‐220‐0064/951‐355‐3348 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. projects@evengineersnet.com http://www.evengineersnet.com Wind Load Cont. 160 mph ASCE 7‐16 Figure 26.5‐1B B 1.0 ASCE 7‐16 Sec 26.8.2 0.57 ASCE 7‐16 Table 26.10‐1 0.85 ASCE 7‐16 Table 26.6‐1 1.00 ASCE 7‐16 Table 26.9‐1 31.74 psf 18.0 Degrees 1.5 Conservatively assuming all exposed 0.8 conservatively assuming 10 ft2 effective area Uplift (W)Zone(1,2e) Zone(2r, 2n) Zone(3e) Zone(3r) Fig. 30‐3‐2 GCp=‐1.1 ‐2 ‐2 ‐2.4 Eq. 29.4‐7 P=qh(GCp)(γE)(γa)=‐41.89 ‐76.17 ‐76.17 ‐91.41 GCp=0.5 Figure 30.3‐2 P=qh(GCp)(γE)(γa)=19.04 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 Average Trib Width Area (ft) Uplift (lbs) Down (lbs) Zone(1,2e)4 11.0 222.2 181.9 Zone(2r, 2n)4 11.0 391.9 181.9 Zone(3e)4 11.0 391.9 181.9 Zone(3r)4 11.0 467.3 181.9 Conservative Max=467.3 < 760 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. KZ = Kd = Ke = qh= 0.00256KzKztKdKeV2= Pitch = γE= γa= Lag Screw Penetration KZt = Risk Category =II V= Exposure = projects@evengineersnet.com http://www.evengineersnet.com Vertical Load Resisting System Design Trusses Max Length, L = 6.0 ft (Beam maximum Allowable Horizontal Span) Tributary Width, WT =24 in Dr =10psf 20 plf Lr =20 psf Wdown=19.04 psf 38.1 plf Pv= 3 psf 6 plf Load Case: DL+0.6W (CD=1.6) Pv max Shear= 181.9 lbs Max Moment, Mu =147 lb‐ft Conservative Max Shear, Vu=wL/2+Pv Point Load =260 lb Note: Proposed loading will add less than 5% of the existing loads. Member Capacity DF‐L No.2 2X4 CL CF Ci Cr KF φλ 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 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 =0.23 < 1 Satisfactory Allowable Shear, Vall = 2/3Fv'A =630.0 lb DCR=Vu/Vall =0.41 < 1 Satisfactory Design Value Adjusted Value projects@evengineersnet.com http://www.evengineersnet.com Siesmic Loads Check Roof Dead Load 10 psf % or Roof with Pv 61.7% Dpv and Racking 3 psf Average Total Dead Load 11.9 psf Increase in Dead Load 9.3%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 ‐ WIDMAN RUDOLPH. The analysis was according to applicable building codes, professional engineering and design experience, opinions and judgments. The calculations produced for this dwelling'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. projects@evengineersnet.com http://www.evengineersnet.com