The URL can be used to link to this page

Home My WebLink AboutPV2022-079 - MiscPJ 2on2 ul vl W5 Ibalttd-ert Ter 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 Structural Calculations for a Roof Mounted Solar Photovoltaic System for: David &Victoria Collins Residence (*Exp. ROFEss ro1615 Bayadere Terrace,Newport Beach, CA 92625No. C58724 3-31.23 Applicable Codes: 2019 California Building Code, 2019 California Electric Code, `� 2019 California Mechanical Code, American Society of Civil Engineers Standard ASCE 7-16 Minimum Design Loads for Buildings and Other Structures, American Wood Council 2018 National Design Specification for Wood Construction, Local Municipal Code, and all other codes which are adopted by reference or enacted by law. Assumed Design Parameters: The existing structure has been built under a building permit and is in its original condition. The existing roof structure is capable of its code required live load and the ability of the roof structure to support live loads has not been substantially reduced by the age of the structure, termites or mold, or unauthorized modifications to the existing structure. Solar Energy Contractor shall make inspection of the existing roof framing system prior to installation of the roof mounted solar energy system to verify that the existing roof is capable of supporting minimum roof live loads. Assumed Design Parameters: All 2x members are grade Douglas Fir #2 or better All 4x members are grade Douglas Fir #1 or better All Roof Connectors are Simpsons Strong -Tie or Equal 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. Sht # 1 of 7 2022-1352 Green Road Solar Date: March 24, 2022 David & Victoria Collins Residence 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 Note to Building Official: Based upon a review of the proposed plans I am confident that the existing roof framing system is capable of safely supporting the additional loads caused by the solar photovoltaic energy system. The contractor shall field verify that the existing roof structure is in its original permitted 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. Check 2x4 Rafters 0-) 24" O.C.*: (Assume max rafter span = 6.9 ft.) wDL+LL w = 30 psf x 2 ft. = 60 pif I 9 R1 R2 6.9' Total load on rafter = 60 plf x 6.9 ft. = 414 Ibs No. C58724 Exp. 3-31-23 C *Note: Contractor to Field Verify Framing Sht # 2 of 7 2022-1352 Green Road Solar Date: March 24, 2022 David & Victoria Collins Residence 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 2x4 Rafters (a)_ 24" O.C.: P P P 6 66 w DL wDL.LL=30psfx2ft. =60pif I I I R1 R2 Total load on rafter = 28 plf x 6.9 ft. + ( 4' x 2.75' x 3 psf x 3 ) = 292 Ibs < 414 Ibs OK Check attachment of Support to Existina Structure for Wind Uplift CHECK SOLAR STRUCTURE ATTACHMENTS PER ASCE 7-16 WIND 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 2022-1352 Green Road Solar David & Victoria Collins Residence No. C58724 Exp.3.31-23 Sht # 3 of 7 Date: March 24, 2022 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 For Sloped Roof Connection: Tributary Area to Each Solar Mount = 4 ft. x 2.75 ft. = 11 sq. ft. ( Max) Calculate Design Wind Pressure at each support (Wind Speed 110 mph Exposure C): p=gh(GCp)(yE)(y.) Eq'n 29.4-7 ASCE 7-16 qh=0.00256KZKZtKdK,V2 Eq'n 26.10-1 ASCE 7-16 Note: KZ = velocity pressure coefficient, Section 26.10.1 ASCE 7-16 KZ = 0.9 (Exposure C, Height = 20 ft or less) w. KZt = Topographical Factor = 1.0 LNo.Kd = Wind Directionality Factor = 0.85 Ke = Ground Elevation Factor= 1.0 V = 110 mph; VASD= 85 mph Table 1609.3.1 2019 CBC qh = 0.00256 (0.9) (1.0) (0.85) (1.0) (85)2 qh =14.1 psf GCp = -2.0 (Zone 2 ; Effective Area = 15 sq. ft. ) YE = Exposure Factor = 1.5 y,, = Solar Array Pressure Equalization Factor = 0.7 Fig. 29.4-8 ASCE 7-16 p = qh (GCp) (YE) (Y. ) p =14.1 psf (-2.0) (1.5) (0.7) = -29.7 psf Nominal (Unfactored) Uplift at each support = 29.7 psf x 11 sq. ft. = 327 Ibs Note: Section 2.4.1 of ASCE 7-16, Basic Load Combinations for Allowable Stress Design. Note: Applicable Load Combination #5 (D + 0.6W) Sht # 4 of 7 2022-1352 Green Road Solar Date: March 24, 2022 David & Victoria Collins Residence 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 Dead Load = 3.0 psf Wind Load = 29.7 psf Design (Factored) Load at each support: 3 psf + (0.6 x 29.7 psf) = 20.8 psf where: Y = Distance between 2 lag screws = 1.2" Y' = Moment arm to 1 st lag screw = 5.6" Moment due to Load = (20.8 psf x 11 sq. ft.) x 5.6 inches = 1,281 in -lb Load to lag screw = 1,281 in -lb / 1.2 in = 1,068lbs Determine allowable load per 5/16" lag screw w/ 3.25" embedment into wood below according to the 2018 NDS. W ' = W x Cd x Ct Table 10.3.1 2018 NDS where: W = 266 Ibs / 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 Ibs/ in. x 3.25 in. x 1.6 x 1.0 = 1,383 Ibs > 1,068 Ibs OK OK. Use Tile Hooks with (2) 5/16" x 3.5" Lag Screws with 3.25" min. embedment into wood, at 48" O.C. max, as per Plans to Manufacturer's instructions. No. C58724 Exp.3-31-23 [0, Sht # 5 of 7 2022-1352 Green Road Solar Date: March 24, 2022 David & Victoria Collins Residence 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 For Flat Roof Connection: Design (Factored) Uplift at each support = 0.6 x 327 Ibs = 196 Ibs Load per lag screw = 196 Ibs / 1 = 196 Ibs 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 Ibs / 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 Ibs/ in. x 2.5 in. x 1.6 x 1.0 = 1,064 Ibs > 196 Ibs OK Use Support connected to 2x Min. Roof Member w/ (1) 5/16" x 3.5" lag screw per connection minimum. No. C58724 Exp. 3-31-23 Sht # 5.1 of 7 2022-1352 Green Road Solar Date: March 24, 2022 David & Victoria Collins Residence 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 5,700 sq. ft. Approximate Effective = Seismic Weight DETERMINE BASE SHEAR V=CsW Cs SDS = rR]le 5,700 sq. ft. x 30 psf ave. = 171,000 LBS EQ'N 12.8-1 ASCE 7-16 EQ'N 12.8-2 ASCE 7-16 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= 2/3x1.8=1.2 1.2 Cs = �6.5] = 0.185 1 2022-1352 Green Road Solar David & Victoria Collins Residence EQ'N 12.8-2 ASCE 7-16 No. C58724 Exp. 3-31-23 Sht # 6 of 7 Date: March 24, 2022 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 171,000 LBS = 31,635 LBS EQ'N 12.8-1 ASCE 7-16 DETERMINE NEW BASE SHEAR Determine Seismic Weight of Building with Solar Array: EXISTING SEISMIC = 171,000 LBS WEIGHT NEW SOLAR ARRAY = 3 PSF x 54 PANELS x 3.3' x 5.5' = 2,940 LBS NEW _SEISMIC__ = 171,000 LBS + 2,940 LBS = 173,940 LBS WEIGHT THEREFORE NEW BASE SHEAR: V = 0.185 x 173,940 = 32,179 LBS EQ'N 12.8-1 ASCE 7-16 % CHANGE = 32,179 LBS - 31,635 LBS x 100 = 1.7 0/6< 10% OK 31,635 LBS BUILDING DI OK. PER ASCE 7-16 SECTION 11.13.3 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 05/04/2022 BY: Y.T. gROFESS/pNq W.lu r 2 LNo. C58724 Exp.3-31-23 O w \- �OF C A0F0� Sht # 7 of 7 2022-1352 Green Road Solar Date: March 24, 2022 David & Victoria Collins Residence