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Home My WebLink AboutPV2022-065 - Misc� is ��Ip-2 oar �► �� . Loyd W. Martin Professional Engineer, Inc. 9924 Universal Boulevard #224-406 Orlando, FL 32819 Te1:1.310.464.1804 Email: loydwmartin@gmail.com www.loydwmartin.com Structural Calculations for a Roof Mounted Solar Photovoltaic System for: Elizabeth Hunt Residence 16 Cape Danbury, ��QROFESS/p�� Newport Beach, CA 92660 r y No. C58724 Applicable Codes: 2019 California Building Code, 20 2019 California Mechanical Code, Standard ASCE 7-16 Minimum bE Structures, American Wood C6"" - for Wood Construction, Lo l M4 are adopted by reference 44noa Assumed Design Exp. 3.31.23 'ic Code, of Civil Engineers *ngs and Other which \\� SSC UROi,nG,ST�y�1p`SFA�� o'cp The existing structure has been b original condition. The existing roof st uctur FeC i �!b its required live load and the ability of the ro s Its Eve has not been substantially reduced by the a b, ort Cave loads �, tr��t�re, termites or mold, or unauthorized modifications to the existif 6d.. s # . Solar Energy Contractor shall make an inspection of the existing(aming system prior to installation of the roof mounted solar energy sy tem to verify that the existing roof is capable of supporting minimum roof live loads. Assumed Design Parameters: BUILDING DIVISION All 2x members are grade Douglas Fir #2 or better All 4X members are grade Douglas Fir #1 or better All Roof Connectors are Simpson Strong -Tie or Equal BY YT All Concrete Foundations are fc = 2500 psi or stronger Original Structure was built to the Type -V Wood Framed Standards of the Applicable Building Code at the time of Construction. 2022-1107 Effect Energy Elizabeth Hunt Residence Sht # 1 of 7 Date: March 15, 2021 Loyd W. Martin Professional Engineer Inc 9924 universal Boulevard #224-406 Orlando, FL 32819 Tel:1.310.464.1804 Email: loydwmartin@gmail.com www.Ioydwmartin.com Note to Building Official: Based upon a review of the proposed plans and information, the existing roof framing system is capable of safely supporting the additional loads caused by the new solar photovoltaic energy system. The contractor shall field verify that the existing roof structure is in its original permited condition and verify that it can support the normal code required roof live loads. Attached in this package are several calculations showing that the roof members can support the additional weight of the solar array. Furthermore, an analysis of the solar array's support for wind forces and a seismic analysis of the existing structure are also included. =AMuna Lx4 Koot Ratters iL 24" fB fv • * o max rafter span = 7.8 ft.) `�` No. C58724 * Exp. 3.31.23 W oL. LL = 30 psf x 2 ft. = 60 plf 9 R1 Total load on rafter = 60 plf x 7.8 ft. = 468 lbs -Note: Contractor to Field Verify Framing 9 7.8' R2 2022-1107 Effect Energy Elizabeth Hunt Residence Sat # 2 of 7 Date: March 15, 2021 Loyd W. Martin Professional Engineer, Inc. 9924 Universal Boulevard #224-406 Orlando, FL 32819 Tel:1.310.464.1804 Email:loydwmartin@gmail.com www.loydwmartin.com Check Existing 2x4 Roof Rafters A- 24" O.C.: P P P P P wWLL DL6 66 66 9 � R1 w DL+LL = 30 psf x 2 ft. = 60 plf M Total load on rafter = 28 plf x 7.8 ft + (6'x 1.65'x 3 psf x 5 ) = 367 lbs < 468 lbs OK Check attachment of Support to Existing Structure for Wind Uplift ZN CHECK SOLAR STRUCTURE ATTACHMENTS PER ASCE 7-16WIND LOADS ON BUILDING APPURTENANCES AND OTHER STRUCTURES Section 29.4.4 THEREFORE CHECK ATTACHMENT FOR TYPICAL CRITICAL LOAD WHICH IS THE EDGE ZONE - ZONE 2. NOTE: PER DEFINITION ON SHEETS 246 & 247 OF ASCE 7-16 EFFECTIVE WIND AREA: "FOR ROOFTOP SOLAR ARRAYS, THE EFFECTIVE WIND AREA IN FIG. 29.4-7 IS EQUAL TO THE TRIBUTARY AREA FOR THE STRUCTURAL ELEMENT BEING CONSIDERED, EXCEPT THAT THE WIDTH OF THE EFFECTIVE WIND AREA NEED NOT BE LESS THAN ONE-THIRD ITS LENGTH." EFFECTIVE AREA = 15 SQ FT No. C58724 Exp. 3-31-23 —� Sht # 3 of 7 2022-1107 Effect Energy Elizabeth Hunt Residence Date: March 15, 2021 Loyd W. Martin Professional Engineer, Inc. 9924 Universal Boulevard #224-406 Orlando, FL 32819 Tel:1.310.464.1804 Email: loydwmartin@gmail.com www.loydwmartin.com Check attachment of Support to Existing Structure for Wind Uplift - Cont'd Tributary Area to Each Solar Mount = 6 ft. x 2.75 ft. = 16.5 sq. ft. ( Max ) Calculate Design Wind Pressure at each support (Wind Speed 130 mph Exposure C): p=gh(GCp)(yE)(ya) Eq'n 29.4-7 ASCE 7-16 qh= 0.00256 KZKatKdK, r Eq'n 26.10-1 ASCE 7-16 Note: KZ = velocity pressure coefficient Section 29. 10.1 ASCE 7-16 Kz = 0.9 (Exposure C, Height = 20 ft or less) Kzt = Topographical Factor= 1.0 Kd = Wind Directionality Factor = 0.85 Ke = Ground Elevation Factor = 1.0 V = 130 mph; VASB=I 01 mph Table 1609.3.1 2019 CBC qh = 0.00256 (0.9) (1.0) (0.85) (1.0) (101)2 qh = 20 psf GCp = -2.0 (Zone 2 ; Effective Area = 15 sq. ft. ) yE = Exposure Factor = 1.5 7a = Solar Array Pressure Equalization Factor = 0.7 P = qh (GC,) (YE) (7a) p = 20 psf (-2.0) (1.5) (0.7) = 42 psf No. C58724 Exp. 3-31.23 �—("IVI\i Fig. 29.4-8 ASCE 7-16 Nominal (Unfactored) Uplift at each support = 42 psf x 16.5 sq. ft. = 693 lbs Note: Section 2.4.1 of ASCE 7-16, Basic Load Combinations for Allowable Stress Design. Note: Applicable Load Combination #5 (D + 0.6W) Design (Factored) Uplift at each support = 0.6 x 693 lbs = 416 lbs Load per lag screw = 416 lbs / 1 = 416 lbs Sht # 4 of 7 2022-1107 Effect Energy Elizabeth Hunt Residence Date: March 15, 2021 Loyd W. Martin Professional Engineer, Inc. 9924 Universal Boulevard #224-406 Orlando, FL 32819 Tel:1.310.464.1804 Email: loydwmartin@gmail.com www.loydwmartin.com Check attachment of Support to Existing Structure for Wind Uplift - Confd Determine allowable load per 5/16" lag screw w/ 2.5" embedment into wood below according to the 2018 NDS. W'= W x Cd x Ct Table 10.3.1 2018 NDS where: W = 266 lbs / in. of embedment per Table 12.2a Cd = 1.6 per Table 2.3.2 of 2018 NDS Ct = 1.0 per Table 10.3.4 of 2018 NDS W' = 266 lbs/ in. x 2.5 in. x 1.6 x 1.0 = 1,064 lbs > 416 lbs OK Use Support connected to 2x Min. Roof Member w/ (1) 5/16" x 3.5" lag screws per connection minimum. No. C58724 Exp. 3-31.23 Sht # 5 of 7 2022-1107 Effect Energy Elizabeth Hunt Residence Date: March 15, 2021 Loyd W. Martin Professional Engineer, Inc. 9924 Universal Boulevard #224-406 Orlando, FL 32819 Tel:1.310.464.1804 Email:loydwmartin@gmail.com www.loydwmartin.com Check Seismic load due to added dead load of photovoltaic system. Determine Seismic Weight of Existing Building: Effective Existing Seismic Weight Area of (E) Building = Approximately 4,100 Sq. ft. Approximate Effective = 4,100 sq. ft. x 30 psf ave. = 123,000 LBS Seismic Weight DETERMINE BASE SHEAR V = Cs W EQ'N 12.8-1 ASCE 7-16 Cs = SDS EQ'N 12.8-2 ASCE 7-16 �R1 le R = THE RESPONSE MODIFICATION FACTOR IN TABLE 12.2-1 R = 6.5 WOOD SHEAR WALLS le = 1.0 IMPORTANCE FACTOR SDS = 2/3 x SMS EQ'N 11.4- 3 ASCE 7-16 SMS = FA x SS EQ'N 11.4-1 ASCE 7-16 SMS= 1.2x1.5=1.8 SDS = 2/3 x 1.8 = 1.2 1.2 Cs= f 6.51 = 0.185 L1 EQ'N 12.8-2 ASCE 7-16 No. C58724 Exp. 3-31.23 Sht # 6 of 7 2022-1107 Effect Energy Elizabeth Hunt Residence Date: March 15, 2021 Loyd W. Martin Professional Engineer, Inc. 9924 Universal Boulevard #224-406 Orlando, FL 32819 Tel:1.310.464.1804 Email: loydwmartin@gmail.com www.loydwmartin.com EXISTING BASE SHEAR V = 0.185 x 123,000 LBS = 22,755 LBS EQ'N 12.8-1 ASCE 7-16 DETERMINE NEW BASE SHEAR �OQµOFESS/p� Determine Seismic Weight of Building with Solar Array: EXISTING ii?' No. C58724 SEISMIC = 123,000 LBS * Exp. 3.31-23 WEIGHT NEW SOLAR ARRAY = 3 PSF x 18 PANELS x 3.3'x 6.5'= 980 LBS NEW SEISMIC = 123,000 LBS + 980 LBS = 123,980 LBS WEIGHT THEREFORE NEW BASE SHEAR: V = 0.185 x 123,980 LBS = 22,936 LBS EQ'N 12.8-1 ASCE 7-16 % CHANGE = 22,936 LBS - 22,755 LBS x100%=0.8%<10% OK 22,755 LBS OK. PER ASCE 7-16 SECTION 11.B.3 ALTERATIONS EXISTING LATERAL FORCE RESISTING SYSTEM IS EXEMPT FROM ANALYSIS SINCE NEW SEISMIC FORCE IS LESS THAN 10% GREATER THAN EXISTING SEISMIC FORCE. 'Alterations are permitted to be made to any structure without requiring the existing structure to comply with this standard provided the alterations comply with the requirements for a new structure. Alterations that increase the seismic force in any existing structural element by more than 10 percent or decrease the design strength of any existing structural element to resist seismic forces by more than 10 percent shall not be permitted unless the entire seismic force -resisting system is determined to comply with this standard for a new structure. " End of Calculations Sht # 7 of 7 2022-1107 Effect Energy Elizabeth Hunt Residence Date: March 15, 2021