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Report (92) 1�,��.'c'�i\WSJ�J74ir,,T ,,„ ,c_c:\• $VEEPXP R s VSE Project Number:U2801-004-181 July 6,2018 A-R Solar ATTENTION:Michael O'Brien 3211 Martin Luther king Jr Way S,Suite B Seatle,WA 98144 REFERENCE: Durham Education Center Building: 8040 SW Durham Road,Tigard,OR 97224 Solar Array Installation To Whom It May Concern: Per your request, we have reviewed the existing structure at the above referenced site. The purpose of our review was to determine the adequacy of the existing structure to support the proposed installation of solar panels on the roof as shown on the panel layout plan. Based upon our review, we conclude that the existing structure is adequate to support the proposed solar panel installation. Design Parameters Code:Oregon Structural Specialty Code,2014 Edition(2012 IBC) Risk Category:III Design wind speed: 130 mph (3-sec gust)per ASCE 7-10 Wind exposure category:C Ground snow load: 10 psf Existing Roof Structure Roof structure: manufactured trusses @ 24"O.C. Roofing material:metal corrugated Roof pitch:2:12 Connection to Roof Mounting connection(Zone 1):(1) S-5-S Mini at max.48 in.O.C. Mounting connection(Zone 2):(1) S-5-S Mini at max.24 in.O.C. Mounting connection(Zone 3):(1) S-S-S Mini at max. 12 in.O.C. For zone details see Figure 1. Conclusions Based upon our review,we conclude that the existing structure is adequate to support the proposed solar panel installation. The weight of the solar array is 3 psf or less. In the area of the solar array, other live loads will not be present or will be greatly reduced.The gravity loads in the area of the solar array are decreased;thus,the stresses of the structural elements are decreased. Therefore,the requirements of Section 3403.3 of the 2014 OSSC are met and the structure is permitted to remain unaltered. 651 W.Galena Park Blvd.,Ste. 101/Draper, UT 84020/T(801)990-1775/F(801)990-1776/www.vectorse.com VSE Project Number: U2801-002-181 Taco Time Residence V ECT O .. 5/24/2018 E n G I fl E E R S The solar array will be flush-mounted (no more than 6" above the roof surface) and parallel to the roof surface. Thus, we conclude that any additional wind loading on the structure related to the addition of the proposed solar array is negligible. The attached calculations verify the capacity of the connections of the solar array to the existing roof against wind(uplift), the governing load case. Regarding seismic loads, we conclude that any additional forces will be small. With an assumed roof dead load of 9 psf, solar array dead load of 3 psf, and affected roof area of 33% (maximum), the additional dead load (and consequential seismic load)will be 10.9%.This calculation conservatively neglects wall weight.Because the increase in lateral forces is less than 10%, this addition meets the requirements of the exception in Section 3403.4 of the 2014 OSSC. Thus the existing structure is permitted to remain unaltered. Limitations Installation of the solar panels must be performed in accordance with manufacturer recommendations. All work performed must be in accordance with accepted industry-wide methods and applicable safety standards. The contractor shall notify Vector Structural Engineering, LLC should any damage,deterioration or discrepancies between the as-built condition of the structure and the condition described in this letter be found. Connections to existing roof framing must be staggered,except at array ends, so as not to overload any existing structural member. The use of solar panel support span tables provided by others is allowed only where the building type,site conditions,site-specific design parameters, and solar panel configuration match the description of the span tables.The design of the solar panel racking(mounts,rails,etc.),and electrical engineering is the responsibility of others. Waterproofing around the roof penetrations is the responsibility of others. Vector Structural Engineering assumes no responsibility for improper installation of the solar array. VECTOR STRUCTURAL ENGINEERING,LLC OR Firm License:2202 46153MrYc Pq, -Sti 6 �: 7PE r iii II OREGON , 0CP AZ' QS 'T6 2O GR T At-4.1 (EXPIRATIM DAI L 12/31/2019 j 07/06/2018 Roger Alworth,S.E. OR License:41725-Expires:01/27/2020 Principal Enclosures RTA/stb 651 W.Galena Park Blvd.,Ste. 101/Draper, UT 84020/T(801)990-1775/F(801)990-1776/www.vectorse.com JOB NO.: U2801-004-181 SUBJECT: LOAD COMPARISON E r-1 G I n E E R S PROJECT: Durham Education Center Residence Summary of Loads Existing Design With PV Array D [psf] 14 12 Lr[psf] 20 0 S [psf] 11 11 Maximum Gravity Loads: Existing With PV Array D+ Lr[psf] 34 12 ASCE 7-10,Section 2.4.1 D+S [psf] 25 23 ASCE 7-10,Section 2.4.1 Maximum Gravity Load [psf]: 34 23 Ratio Proposed Loading to Current Loading: 68% OK The gravity loads in the area of the solar array are decreased;thus,the stresses of the structural elements are decreased.Therefore,the requirements of Section 3403.3 of the 2014 OSSC are met and the structure is permitted to remain unaltered. a . . , VECTOR E rl G I I1 E E R S VSE Project Number:U2801-004-181 July 6,2018 A-R Solar ATTENTION:Michael O'Brien 3211 Martin Luther king Jr Way S,Suite B Seatle,WA 98144 REFERENCE: Durham Education Center Building:8040 SW Durham Road,Tigard,OR 97224 Solar Array Installation To Whom It May Concern: Per your request, we have reviewed the existing structure at the above referenced site. The purpose of our review was to determine the adequacy of the existing structure to support the proposed installation of solar panels on the roof as shown on the panel layout plan. Based upon our review, we conclude that the existing structure is adequate to support the proposed solar panel installation. Design Parameters Code:Oregon Structural Specialty Code,2014 Edition(2012 IBC) Risk Category:III Design wind speed: 130 mph (3-sec gust)per ASCE 7-10 Wind exposure category:C Ground snow load: 10 psf Existing Roof Structure Roof structure: manufactured trusses @ 24"O.C. Roofing material:metal corrugated Roof pitch:2:12 Connection to Roof Mounting connection(Zone 1):(1) S-5-S Mini at max.48 in.O.C. Mounting connection(Zone 2):(1) S-5-S Mini at max.24 in.O.C. Mounting connection(Zone 3):(1) S-5-S Mini at max. 12 in.O.C. For zone details see Figure 1. Conclusions Based upon our review, we conclude that the existing structure is adequate to support the proposed solar panel installation. The weight of the solar array is 3 psf or less. In the area of the solar array, other live loads will not be present or will be greatly reduced.The gravity loads in the area of the solar array are decreased;thus,the stresses of the structural elements are decreased. Therefore,the requirements of Section 3403.3 of the 2014 OSSC are met and the structure is permitted to remain unaltered. 651 W.Galena Park Blvd.,Ste. 101/Draper, UT 84020/T(801)990-1775/F(801)990-1776/www.vectorse.com