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Home My WebLink AboutPV2022-095 - CalcspN 2Q22-UCJ 6 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: Eric Werner Residence BUILDING DIVISION �OQROFESS/O 1720 Kings Rd., y o Newport Beach, CA 92663 04/11/2022 W No. C587za * Exp. 3-31-23 Applicable Codes Bv:v.r. �oFcn��F��\P 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 an 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 Simpson 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 2022-1611 Effect Energy Eric Werner Residence Date: April 7, 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 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. Check Existinq 2x14 Roof Rafters (cD_ 24" O.C.: * ° d No. C58724 ( Assume max rafter span = 13.5 ft. ) * Exp.3-31-23 W DL+LL yrFOFCpL �Q.\ w DL+LL = 30 psf x 2 ft. = 60 plf 9 R1 Total load on rafter = 60 pif x 13.5 ft. = 810 Ibs *Note: Contractor to Field Verify Framing 9 13.5' R2 Sht # 2 of 7 2022-1611 Effect Energy Eric Werner Residence Date: April 7, 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 Existinq 2x14 Roof Rafters A- 24" O.C.: P P P P wWL LLb b6 6® 9 1 W DL+LL = 30 psf x 2 ft. = 60 plf R1 R2 13.5' 12' 1.5' Total load on rafter = 60 pif x 1.5 ft + 28 plf x 12 ft + ( 6' x Tx 3 psf x 4 ) = 642 Ibs < 810 Ibs OK Check attachment of Support to Existing 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 No. C58724 Exp. 3.31-23 Sht # 3 of 7 2022-1611 Effect Energy Eric Werner Residence Date: April 7, 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 Tributary Area to Each Solar Mount = 6 ft. x 3 ft. = 18 sq. ft. ( Max ) Calculate Design Wind Pressure at each support (Wind Speed 130 mph Exposure C): p = qh (GCP) (YE) (Ya) qh = 0.00256KZKZtKdKe r Eq'n 29.4-7 ASCE 7-16 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 = 130mph; VASB= 101 mph Table 1609.3.1 2019 CBC qh = 0.00256 (0.9) (1.0) (0.85) (1.0) (101)' qh = 20 psf GCp = -2.0 (Zone 2 ; Effective Area = 15 sq. ft. ) YE = Exposure Factor = 1.5 Ya = Solar Array Pressure Equalization Factor = 0.7 p = qh (GC,) (YE) (Ya ) p = 20 psf (-2.0) (1.5) (0.7) = 42 psf No. C58724 Exp. 3.31-23 Fig. 29.4-8 ASCE 7-16 Nominal (Unfactored) Uplift at each support = 42 psf x 18 sq. ft. = 756 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) Design (Factored) Uplift at each support = 0.6 x 756 Ibs = 454 Ibs Load per lag screw = 454 Ibs / 1 = 454 Ibs Sht#4 of 7 2022-1611 Effect Energy Eric Werner Residence Date: April 7, 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 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 > 454 Ibs OK Use Support connected to 2x Min. Roof Member w/ (1) 5/16" x 3.5" lag screws per connection minimum. 24 ll*� Exp.3-31723 Sht # 5 of 7 2022-1611 Effect Energy Eric Werner Residence Date: April 7, 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 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 1,700 sq. ft. Approximate Effective = 1,700 sq. ft. x 30 psf ave. = 51,000 LBS Seismic Weight DETERMINE BASE SHEAR CtExp. V = Cs W EQ'N 12.8-1 ASCE 7-16 SDs Cs = EQ N 12.8-2 ASCE 7-16 le R 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 6.5] = 0.185 L1 EQ'N 12.8-2 ASCE 7-16 Sht # 6 of 7 2022-1611 Effect Energy Eric Werner Residence Date: April 7, 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 51,000 LBS = 9,435 LBS EQ'N 12.8-1 ASCE 7-16 DETERMINE NEW BASE SHEAR Determine Seismic Weight of Building with Solar Array: w. � o EXISTING E2 No. C58724 SEISMIC = 51,000 LBS * Exp.3-31-23 WEIGHT NEW SOLAR ARRAY = 3 PSF x 40 PANELS x 3.3' x 6' = 2,376 LBS NEW SEISMIC = 51,000 LBS + 2,376 LBS = 53,376 LBS WEIGHT THEREFORE NEW BASE SHEAR: V = 0.185 x 53,376 LBS = 9,875 LBS EQ'N 12.8-1 ASCE 7-16 % CHANGE = 9,875 LBS - 9,435 LBS x 100 % = 4.7 % < 10% OK 9,435 LBS 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 fora new structure." End of Calculations Sht # 7 of 7 2022-1611 Effect Energy Eric Werner Residence Date: April 7, 2022