Loading...
31B-086 JB-0101926-00 Reva_Calcs_ENP_MA_TBD s Version #54.7 - TBD RE: CERTIFICATION LETTER Project/Job # 0101926 Project Address: Griggs Residence 9 Barrett Place **COGEN** Northampton, MA 01060 AHJ NorthamptonSC Office Springfield Design Criteria: - Applicable Codes = MA Res. Code, 8th Edition, ASCE 7-05, and 2005 NDS - Risk Category = II - Wind Speed = 90 mph, Exposure Category C - Ground Snow Load = 40 psf - MP6: Roof DL = 9.5 psf, Roof LL/SL = 28 psf (Non-PV Areas), Roof LL/SL = 16.4 psf (PV Areas) - MP7: Roof DL = 9.5 psf, Roof LL/SL = 28 psf (Non-PV Areas), Roof LL/SL = 16.4 psf (PV Areas) Note: Per IBC 1613.1; Seismic check is not required because Ss = 0.22462 < 0.4g and Seismic Design Category (SDC) = B < D To Whom It May Concern, March 11, 2016 A jobsite survey of the existing framing system of the address indicated above was performed by a site survey team from SolarCity. Structural evaluation was based on site observations and the design criteria listed above. Additionally, I certify that the PV module assembly including all standoffs supporting it have been reviewed to be in accordance with the manufacturer’s specifications and to meet and/or exceed all requirements set forth by the referenced codes for loading. Based on this evaluation, I certify that the existing structure directly supporting the PV system is adequate to withstand all loading indicated in the design criteria above based on the requirements of the applicable existing building and/or new building provisions adopted/referenced above. The PV assembly hardware specifications are contained in the plans/docs submitted for approval. Version #54.7 - TBD X-X Spacing X-X Cantilever Y-Y Spacing Y-Y Cantilever Configuration Uplift DCR MP6 64''24''39''NA Staggered 44.3% MP7 64''24''39''NA Staggered 44.3% X-X Spacing X-X Cantilever Y-Y Spacing Y-Y Cantilever Configuration Uplift DCR MP6 48''20''65''NA Staggered 55.2% MP7 48''20''65''NA Staggered 55.2% Type Spacing Pitch MP6 Pre-Fab Truss @ 16 in. O.C.35° MP7 Pre-Fab Truss @ 16 in. O.C.35° Member Evaluation Results Member Impact Check OK Member Impact Check OK HARDWARE DESIGN AND STRUCTURAL ANALYSIS RESULTS SUMMARY TABLES Mounting Plane Framing Hardware - Portrait Modules' Standoff Specifications Hardware - Landscape Modules' Standoff Specifications Qualification ResultsStructure Landscape Hardware Portrait Hardware Refer to the submitted drawings for details of information collected during a site survey. All member analysis and/or evaluation is based on framing information gathered on site. The existing gravity and lateral load carrying members were evaluated in accordance with the IBC and the IEBC. Overhang 1.66 ft Actual W 1.50'' Span 1 5.51 ft Actual D 3.50'' Number of Spans (w/o Overhang)2 Span 2 5.49 ft Nominal Yes Roofing Material Comp Roof Span 3 A 5.25 in.^2 Re-Roof No Span 4 Sx 3.06 in.^3 Plywood Sheathing Yes Span 5 Ix 5.36 in.^4 Board Sheathing None Total Rake Span 15.46 ft TL Defl'n Limit 120 Vaulted Ceiling No PV 1 Start 1.33 ft Wood Species SPF Ceiling Finish 1/2" Gypsum Board PV 1 End 14.67 ft Wood Grade #2 Rafter Slope 35°PV 2 Start Fb 875 psi Rafter Spacing 16'' O.C.PV 2 End Fv 135 psi Top Lat Bracing Full PV 3 Start E 1400000 psi Bot Lat Bracing At Supports PV 3 End Emin 510000 psi Roof Pitch 9/12 Initial Pitch Adjust Non-PV Areas PV Areas Roof Dead Load DL 9.5 psf x 1.22 11.6 psf 11.6 psf PV Dead Load PV-DL 3.0 psf x 1.22 3.7 psf Roof Live Load RLL 20.0 psf x 0.78 15.5 psf Live/Snow Load LL/SL1,2 40.0 psf x 0.7 ǀ x 0.41 28.0 psf 16.4 psf Total Load (Governing LC)TL 39.6 psf 31.7 psf Governing Load Comb CD CL (+)CL (-)CF Cr D + S 1.15 1.00 0.93 1.5 1.15 Governing Analysis Pre-PV Demand Post-PV Demand Net Impact Result Gravity Loading Check -725 psi -557 psi 0.77 Pass Member Analysis Results Summary Notes: 1. ps = Cs*pf; Cs -roof, Cs -pv per ASCE 7 [Figure 7-2] 2. pf = 0.7 (Ce) (Ct) (Is) pg ; Ce=0.9, Ct=1.1, Is=1.0 Member Design Summary (per NDS) Roof System Properties Member Loading Summary STRUCTURE ANALYSIS - LOADING SUMMARY AND MEMBER CHECK - MP6 Member Properties Summary MP6 Horizontal Member Spans Rafter Properties Roofing Material PV System Type Spanning Vents Standoff (Attachment Hardware) Roof Slope Rafter Spacing Framing Type / Direction Purlin Spacing X-X Purlins Only Tile Reveal Tile Roofs Only Tile Attachment System Tile Roofs Only Standing Seam/Trap Spacing SM Seam Only Wind Design Code Wind Design Method Basic Wind Speed V Fig. 6-1 Exposure Category Section 6.5.6.3 Roof Style Fig. 6-11B/C/D-14A/B Mean Roof Height h Section 6.2 Wind Pressure Exposure Kz Table 6-3 Topographic Factor Kzt Section 6.5.7 Wind Directionality Factor Kd Table 6-4 Importance Factor I Table 6-1 Ext. Pressure Coefficient (Up)GCp (Up)Fig. 6-11B/C/D-14A/B Ext. Pressure Coefficient (Down)GCp (Down)Fig. 6-11B/C/D-14A/B Design Wind Pressure p Equation 6-22 Wind Pressure Up p(up)Wind Pressure Down p(down) Y-Direction Max Allowable Standoff Spacing Landscape 39''Max Allowable Cantilever Landscape NA Standoff Configuration Landscape Max Standoff Tributary Area Trib PV Assembly Dead Load W-PV Net Wind Uplift at Standoff T-actual Uplift Capacity of Standoff T-allow Standoff Demand/Capacity DCR Y-Direction Max Allowable Standoff Spacing Portrait 65'' Max Allowable Cantilever Portrait NA Standoff Configuration Portrait Max Standoff Tributary Area Trib PV Assembly Dead Load W-PV Net Wind Uplift at Standoff T-actual Uplift Capacity of Standoff T-allow Standoff Demand/Capacity DCR 22 sf3.0 psf -276 lbs500 lbs 55.2% 500 lbs 44.3% X-Direction 48''20''Staggered Staggered 17 sf3.0 psf-221 lbs 13.1 psf ALLOWABLE STANDOFF SPACINGS X-Direction 64'' 0.88 p = qh (GCp) -14.2 psf 24'' qh qh = 0.00256 (Kz) (Kzt) (Kd) (V^2) (I)Equation 6-1515.0 psf Wind Pressure -0.95 Wind Pressure Calculation Coefficients 0.85 1.00 0.85 1.0 Velocity Pressure 15 ft Wind Design Criteria ASCE 7-05 Partially/Fully Enclosed Method 90 mph NA C Gable Roof NA NA 16'' O.C. Y-Y Rafters NA No Comp Mount Type C 35° CALCULATION OF DESIGN WIND LOADS - MP6 Mounting Plane Information Comp Roof SolarCity SleekMount™ Overhang 1.66 ft Actual W 1.50'' Span 1 5.51 ft Actual D 3.50'' Number of Spans (w/o Overhang)2 Span 2 5.49 ft Nominal Yes Roofing Material Comp Roof Span 3 A 5.25 in.^2 Re-Roof No Span 4 Sx 3.06 in.^3 Plywood Sheathing Yes Span 5 Ix 5.36 in.^4 Board Sheathing None Total Rake Span 15.46 ft TL Defl'n Limit 120 Vaulted Ceiling No PV 1 Start 1.33 ft Wood Species SPF Ceiling Finish 1/2" Gypsum Board PV 1 End 14.67 ft Wood Grade #2 Rafter Slope 35°PV 2 Start Fb 875 psi Rafter Spacing 16'' O.C.PV 2 End Fv 135 psi Top Lat Bracing Full PV 3 Start E 1400000 psi Bot Lat Bracing At Supports PV 3 End Emin 510000 psi Roof Pitch 9/12 Initial Pitch Adjust Non-PV Areas PV Areas Roof Dead Load DL 9.5 psf x 1.22 11.6 psf 11.6 psf PV Dead Load PV-DL 3.0 psf x 1.22 3.7 psf Roof Live Load RLL 20.0 psf x 0.78 15.5 psf Live/Snow Load LL/SL1,2 40.0 psf x 0.7 ǀ x 0.41 28.0 psf 16.4 psf Total Load (Governing LC)TL 39.6 psf 31.7 psf Governing Load Comb CD CL (+)CL (-)CF Cr D + S 1.15 1.00 0.93 1.5 1.15 Governing Analysis Pre-PV Demand Post-PV Demand Net Impact Result Gravity Loading Check -725 psi -557 psi 0.77 Pass Member Analysis Results Summary Notes: 1. ps = Cs*pf; Cs -roof, Cs -pv per ASCE 7 [Figure 7-2] 2. pf = 0.7 (Ce) (Ct) (Is) pg ; Ce=0.9, Ct=1.1, Is=1.0 Member Design Summary (per NDS) Roof System Properties Member Loading Summary STRUCTURE ANALYSIS - LOADING SUMMARY AND MEMBER CHECK - MP7 Member Properties Summary MP7 Horizontal Member Spans Rafter Properties Roofing Material PV System Type Spanning Vents Standoff (Attachment Hardware) Roof Slope Rafter Spacing Framing Type / Direction Purlin Spacing X-X Purlins Only Tile Reveal Tile Roofs Only Tile Attachment System Tile Roofs Only Standing Seam/Trap Spacing SM Seam Only Wind Design Code Wind Design Method Basic Wind Speed V Fig. 6-1 Exposure Category Section 6.5.6.3 Roof Style Fig. 6-11B/C/D-14A/B Mean Roof Height h Section 6.2 Wind Pressure Exposure Kz Table 6-3 Topographic Factor Kzt Section 6.5.7 Wind Directionality Factor Kd Table 6-4 Importance Factor I Table 6-1 Ext. Pressure Coefficient (Up)GCp (Up)Fig. 6-11B/C/D-14A/B Ext. Pressure Coefficient (Down)GCp (Down)Fig. 6-11B/C/D-14A/B Design Wind Pressure p Equation 6-22 Wind Pressure Up p(up)Wind Pressure Down p(down) Y-Direction Max Allowable Standoff Spacing Landscape 39''Max Allowable Cantilever Landscape NA Standoff Configuration Landscape Max Standoff Tributary Area Trib PV Assembly Dead Load W-PV Net Wind Uplift at Standoff T-actual Uplift Capacity of Standoff T-allow Standoff Demand/Capacity DCR Y-Direction Max Allowable Standoff Spacing Portrait 65'' Max Allowable Cantilever Portrait NA Standoff Configuration Portrait Max Standoff Tributary Area Trib PV Assembly Dead Load W-PV Net Wind Uplift at Standoff T-actual Uplift Capacity of Standoff T-allow Standoff Demand/Capacity DCR 22 sf3.0 psf -276 lbs500 lbs 55.2% 500 lbs 44.3% X-Direction 48''20''Staggered Staggered 17 sf3.0 psf-221 lbs 13.1 psf ALLOWABLE STANDOFF SPACINGS X-Direction 64'' 0.88 p = qh (GCp) -14.2 psf 24'' qh qh = 0.00256 (Kz) (Kzt) (Kd) (V^2) (I)Equation 6-1515.0 psf Wind Pressure -0.95 Wind Pressure Calculation Coefficients 0.85 1.00 0.85 1.0 Velocity Pressure 15 ft Wind Design Criteria ASCE 7-05 Partially/Fully Enclosed Method 90 mph NA C Gable Roof NA NA 16'' O.C. Y-Y Rafters NA No Comp Mount Type C 35° CALCULATION OF DESIGN WIND LOADS - MP7 Mounting Plane Information Comp Roof SolarCity SleekMount™