HomeMy WebLinkAboutLetter; Structural Roof Evaluationrvr&x-%w UE
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May 26, 2021 RECEIVED Design Criteria:
1UN ®1 2021 Design Wind Speed (ASD)- 160 mph
Project Solar Ground Snow Load- 0 psf
631 Spring Dew Lane Permitting Department o Risk Category- II
St. Lucie County g
Lehi, Ut 84043
Exposure category- C
RE: Structural Roof Evaluation for the Ruppert Residence: 288 North Ffa Road, Fort
Pierce, Florida
As per your request, we have evaluated the roof structure under the proposed solar panel array. The
information used to evaluate this structure was gathered by Project Solar on behalf of Right Angle
Engineering. The roof structure consists of pre -manufactured steel frame spaced at 24" on center. The
roof material consists of corrugated metal. The design criteria used to analyze this structure are listed
above and included with this letter. The adopted building codes in this jurisdiction are: the 2020 Florida
Building Code, the 2020 Florida Existing Building Code, and ASCE 7-16.
Florida Existing Building Code (FBC) 2020 section 807.4 indicates that alterations to an existing building
that results in less than a 5% increase in the total stress may be performed without a structural
evaluation of the existing building. As demonstrated in the attached calculations, the additional weight
of the solar panels will be less than 5% increase in the gravity loading and the stress on the existing roof
framing.
Based on our assessment we have determined that the existing roof framing will safely and adequately
support the additional loads imposed by the solar panels without reinforcement. In order for the loads
to be evenly distributed, the roof attachments should be staggered and spread evenly throughout the
panel array. Attachment points should be spaced at a maximum of 48" on center. The racking system
should be installed per the manufacture's specifications. There should be a minimum of 118 S5 Protea
Bracket attachment points to the roof. Waterproofing around the roof penetrations is the responsibility
of others. Right Angle Engineering assumes no responsibility for improper installation of the solar panels.
Regards,
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* No 89045 = �.
STATE OF W,
Robert DSmythe, P.E. ;
Right Angle Engineering///��` '•:cLOR10P.• G�2�� : 10�2
01YA `I�
55 WEST 500 SOUTH, HEBER CITY, UT 84032
T 925,787.3067 U RIGHTANGLEENG.COM
■ .A
Roof Slope
Number of panels
Panel Area
GCp Zone 1
GCp Zone 2
GCp Zone 3
Gcpi
Velocity Pressure (qh)
qh= .00256KhKhtKdV^2
Kh
Kht
Kd
Designed wind pressure (P)
P= gh(GCh) - (GChi))
Zone 1 Pressure (P)
Zone 2 Pressure (P)
Zone 3 Pressure (P)
Shear Capacity
Shear tributary area
Total pullout capacity
Pullout max tributary area
Factor of Safety
Minimum number of connections
Beam Span
Spacing
Roof Framing type
Panel Orientation
Number of Panels per rafter
Panel distance from eave
Bending Moment
Vertical Reaction' (V1)
'VerticalReaction (V2)'
3
20 degrees
24
420 ft^2
-1
Figure 30.3-(2A-5B)
-1.8
Figure 30.3-(2A-5B)
-2.8
Figure 30.3-(2A-5B)
0.18
Table 26.13-1
54.6 psf
Equation 26.10-1
0.98
Table 26.10-1
1
Equation 26.8-1
0.85
Table 26.6-1
psf
Equation 30.8-1
-64.4
-108.1
-162.7
49
47.8
364
3.4
1.11
118
psf
psf
psf
Ibs
ft^2
Ibs
ft^2
S-5 Load Testing
S-5 Load Testing
RECEIVED
JUN 0 a 2021
12 ft
2 ft Permitting Department
pre -manufactured steel St. Lucie County
frame
landscape
4
0
Without;Solar. ° .,:With Solar. Percent°
Panels, Panels Increase
1200.6 ft-Ibs 539.1 ft-Ibs 44.9% Less than 105%
400.2 Ibs 181.9 Ibs 45.5% Less than 105%
400.2 Ibs 181.05 Ibs 45.2516 Less than 105%
I ■ ,
NOW L"
Design Wind Speed (3 second gust)
160 mph
Exposure Category
C
Risk Category
2
Mean Roof Height
30 ft
Roof Type
Gable Roof
Building Type
enclosed
Corrugated Metal
1.5
psf
5/8" Plywood Sheathing
2
psf
Roof Framing
4
psf
Insulation
3.85
psf
Gypsum sheathing
2
psf
Solar Panel Array
3
psf
Dead Load Without Panels
13.35
psf
Dead Load With Solar panels
16.35
psf
Roof Live Load
Existing Roof Live Load
20
psf ASCE 7-16 Table 4.3-1
Roof Live Load with Solar Panels
0
psf 2020 FBC 1607.12.5.1
Ground Snow Load (pg)
0 psf
Section 7.2
Exposure Factor (Ce)
0.9
Table 7.3-1
Thermal Factor (Ct)
1.1
Table 7.3-2
Importance Factor (Is)
1
Table 1.5-2
Flat Roof Snow Load (Pf)
0
Equation 7.3-1
Slippery surface Slope Factor (Cs)
0.83
Figure 7-2
Nonslippery Surface Slope Factor
(Cs)
1
Figure 7-2
Roof Snow Load
0 psf
Equation 7.4-1
Reduced Roof Snow Load (Slippery
Surface)
0 psf
Equation 7.4-1
With'Sblar, „
Without Solar Panels panels
D +, Lr 33.4 psf 16.4 psf
D+ S 13.4 psf 16.4 psf
2