HomeMy WebLinkAboutBerger, Blair Retrofit Letter SS VECTOR
E n G I n E E R S
VSE Project Number:U3507.0114.211
October 15,2021
TruNorth Solar LLC
ATTENTION: Donna Pickard
3735 Dunlap St.N.
Arden Hills,MN 55112
REFERENCE: Berger,Blair Residence: 5771 West Moore Lake Drive Northeast,Fridley,MN 55432
Solar Array Installation
To Whom It May Concern:
Per your request, we have reviewed the existing structure at the above referenced site. The purpose of our review was to
determine the adequacy of the existing structure to support the proposed installation of solar panels on the roof as shown on
the panel layout plan.
Based upon our review,we conclude that the existing structure of the western roof will require a retrofit per the
attached detail in order to support the proposed solar panel installation.The required sister size is 1-3/4X5-1/2 LVL.
Design Parameters
Code: 2020 Minnesota Building Code(2018 IBC)
Risk Category:II
Design wind speed,Vult: 109 mph (3-sec gust)per ASCE 7-16
Wind exposure category: C
Ground snow load,Pg: 50 psf
Connection to Roof
Mounting connection: (1)5/16" lag screw w/min.2.5"threaded embedment into framing
Maximum mounting spacing along rails:
Zone 1,2e(Beyond 4'from roof edge or within 4'of roof edge perpendicular to slope):48" o.c.
Zone 2n,2r,3e(Within 4'of roof edge parallel w/slope,4'of roof ridge,or 4'of eave-eave corner):48" o.c.
Zone 3r(Within 4'of ridge-eave corner): 24" o.c.
(2)rails per row of panels,evenly spaced;panel length perpendicular to the rails not to exceed 72.5 in.Rail cantilever shall
not exceed 50%of connection spacing.
Conclusions
Based upon our review, we conclude that the existing structure of the western roof will require a retrofit per the attached
detail in order to support the proposed solar panel installation. See attached calculations.
The solar array will be flush-mounted (no more than 10" above the roof surface) and parallel to the roof surface. Thus, we
conclude that any additional wind loading on the structure related to the addition of the proposed solar array is negligible.
The attached calculations verify the capacity of the connections of the solar array to the existing roof against wind (uplift),
the governing load case. Because the increase in lateral forces is less than 10%, this addition meets the requirements of the
exception in Section 806.3 of the 2020 Minnesota Conservation Code for Existing Buildings.Thus the existing lateral force
resisting system is permitted to remain unaltered.
651 W. Galena Park Blvd.,Ste. 101/Draper, UT 84020/T(801)990-1775/F(801)990-1776/www.vectorse.com
VSE Project Number: U3507.0114.211
Berger,Blair Residence
YE C T O R 10/15/2021
E n G i n E E R s
Limitations
Installation of the solar panels must be performed in accordance with manufacturer recommendations. All work performed
must be in accordance with accepted industry-wide methods and applicable safety standards. The contractor must notify
Vector Structural Engineering, LLC should any damage, deterioration or discrepancies between the as-built condition of the
structure and the condition described in this letter be found. Connections to existing roof framing must be staggered, except
at array ends, so as not to overload any existing structural member. The use of solar panel support span tables provided by
others is allowed only where the building type, site conditions, site-specific design parameters, and solar panel configuration
match the description of the span tables.The design of the solar panel racking(mounts,rails, etc.) and electrical engineering
is the responsibility of others. Waterproofing around the roof penetrations is the responsibility of others. Vector Structural
Engineering assumes no responsibility for improper installation of the solar array.
VECTOR STRUCTURAL ENGINEERING,LLC
♦♦``��11DI111J��,,'
LICENSED �'�
m: PROFESSIONAL .
ENGINEER -
10/15/2021
Brett Veazie,P.E.
I hereby certify that this plan,specification or report was prepared
Project Engineer by me or under my direct supervision and that lam a duly Licensed
Professional Engineer under the laws of the State of NEnnesota.
Enclosures Brett Veazie,License No.56392,
Eqiration Date:30-June-2022
BDV/jtg
651 W. Galena Park Blvd.,Ste. 101/Draper, UT 84020/T(801)990-1775/F(801)990-1776/www.vectorse.com
S0016
Copyright @ 2020
Vector Structural Engineering,LLC
This drawing contains proprietary information belonging to
Vector Structural Engineering,LLC,and maybe neither
wholly nor partially copied or reproduced without the prior
E n a I In E E FZ 8 written permission of Vector Structural Engineering,LLC.
DRAPER, UTAH
(BO 1 ) 990- 1 775
WWW.VECTOR.SOLAR.COM SUBJECT SISTERED RAFTER RETROFIT
EXISTING
� RIDGE BOARD
�(2) 16d SINKERS
OR 10d COMMON
NAILS EA. END �� �
i
�p'�• � o� �• EXISTING RAFTER
1 �
NEW SISTERED RAFTER, SIZE PER
LETTER. ATTACH TO EXISTING RAFTER
�1" TYP. w/ 16d STAGGERED SINKERS OR
EXISTING ROOF 10d COMMON NAILS
SHEATHING i
�— - — — — — — — — — — — — — — — — — — — — — — —
i
/ EXISTING
III CEILING JOIST,
III WHERE OCCURS
EXISTING
BEARING WALL
���` LICENSED
`EXISTING ROOF _=m: PROFESSIONAL
SHEATHING _ ENGINEER
N Q-
SISTERNEW RAFTER w/
NAILING PER EXISTING 10/15/2021
ABOVE RAFTER 1 hereby certify that this plan,specification or report
SECTION was prepared by me or under my direct supervision
and that I am a duly Licensed Professional Engineer
NOTES: under the laws of the State of Minnesota,
1. GRADE OF NEW DIMENSIONAL LUMBER SHALL BE SPF #2, DFL #2, OR Brett D.Veazie, License No.56392,
BETTER. LAMINATED VENEER LUMBER (LVL) SHALL BE Fb = 2600 psi, Expiration Date:30-June-2022
Fv = 285 psi, E = 1.9x106 psi OR BETTER.
2. CONSULT ENGINEER WHERE CONDITIONS DIFFER FROM THAT SHOWN.
3. THE SISTERED RAFTER MAY BE INSTALLED AS TWO SEPARATE LENGTHS
WITH ONE LENGTH INSTALLED ON EACH SIDE OF THE EXISTING RAFTER.
THE TWO SEPARATE LENGTHS SHALL OVERLAP A MINIMUM DISTANCE OF
3'-0". ALL OTHER REQUIREMENTS OF THE DETAIL ABOVE APPLY.
4. RETROFIT REQUIRED @ ROOF AREAS SUPPORTING SOLAR PANELS ONLY,
U.N.O. IN LETTER.
JOB NO.: U3507.0114.211
YETO R SUBJECT: WIND PRESSURE
n G I n E E R S
PROJECT: Berger, Blair Residence
Com onents and Cladding Wind Calculations
Label: ISolar Panel Array Note: Calculations per ASCE 7-16
SITE-SPECIFIC WIND PARAMETERS:
Basic Wind Speed [mph]: 109 Notes:
Exposure Category: C
Risk Category: II
ADDITIONAL INPUT & CALCULATIONS:
Height of Roof, h [ft]: 25 (Approximate)
Comp/Cladding Location: Gable Roofs 7°<0 <_ 20°
Enclosure Classification: Enclosed Buildings
Zone 1, 2e GCp: 2.00 Figure 30.3-213 Zone 1, 2e Ya: 0.77 Fig.
Zone 2n, 2r, 3e GCp: 2.88 (negative coeff.) Zone 2n, 2r, 3e Ya: 0.77 29.4-8
Zone 3r GCp: 3.60 Zone 3r Ya: 0.80
a: 9.5 Table 26.11-1
z9 [ft]: 900 Table 26.11-1
Kh: 0.95 Table 26.10-1
Ke: 0.97 Table 26.9-1
KZt: 1 Equation 26.8-1
Kd: 0.85 Table 26.6-1
Velocity Pressure, qh [psf]: 23.7 Equation 26.10-1
YE: 1.50 Section 29.4.4
WIND PRESSURES: Equation 29.4-7 p = q h(GC pAYEAYQ)
Zone 1, 2e, p [psf]: 54.4 psf (1.0 W)
Zone 2n, 2r, 3e, p [psf]: 78.4 psf (1.0 W)
Zone 3r, p [psf]: 102.2 psf (1.0 W)
(a = 3 ft)
JOB NO.: U3507.0114.211
YETO R SUBJECT: CONNECTION
n G In E E R S
PROJECT: Berger, Blair Residence
Calculate Uplift Forces on Connection
Pressure Max Trib. Width 1 2 Max Trib. Max Uplift
(0.6 Dead -0.6 Wind) Area Force
(psf) (ft) (ft2) (Ibs)
Zone 1, 2e 30.8 4.0 12.1 373
Zone 2n, 2r, 3e 45.2 4.0 12.1 547
Zone 3r 59.5 2.0 6.0 360
Calculate Connection Capacity
Lag Screw Size [in]: 5/16
Cd: 1.6 NDS Table 2.3.2
Embedment3 [in]: 2.5
Grade: SPF (G = 0.42)
Nominal Capacity [Ibs/in]: 205 NDS Table 12.2A
Number of Screws: 1
Prying Coefficient: 1.4
Total Capacity [Ibs]: 586
Determine Result
Maximum Demand [lbs]:l 547
Lag Screw Capacity [lbs]:1 586
Result: Capacity > Demand, Connection is adequate.
Notes
1. 'Max Trib. Width' is the width along the rails tributary to the connection.
2. 'Max Trib Area' is the product of the 'Max.Trib Width' and 1/2 the panel width/height perpendicular to the
rails. (2) rails per row of panels. Length of panels perpendicular to the rails shall not exceed 73".
3. Embedment is measured from the top of the framing member to the beginning of the tapered tip of the lag
screw. Embedment in sheathing or other material is not effective.The length of the tapered tip is not part of the
embedment length.
JOB NO.: U3507.0114.211
YET O R SUBJECT: GRAVITY LOADS
n G I n E E R S
PROJECT: Berger, Blair Residence
GRAVITY LOADS Roof Pitch: 4.0 :12
Design material Increase due to Material weight
ROOF DEAD LOAD (D) weight [psf] pitch [psf]
Composite Shingles 2.1 1.05 2.0
1/2" Plywood 1.1 1.05 1.0
Framing* 0.0 0.0
Insulation 0.0 0.0
1/2" Gypsum Clg. 0.0 1.05 0.0
M, E & Misc 2.0 2.0
Total Existing Roof DL 5.2
PV Array DL 3.2 1.05 3
*Self weight of framing members calculated on beam analysis page
ROOF LIVE LOAD (Lr)
Existing Design Roof Live Load [psf] 20 ASCE 7-16 Table 4.3-1
Roof Live Load With PV Array [psf] 0 2020 MBC, Section 1607.13.5
SNOW LOAD (S): Existing w/ Solar Array
Roof Slope [x:12]: 4.0 4.0
Roof Slope [°]: 18 18
Ground Snow Load, pg [psf]: 50 50 ASCE 7-16, Section 7.2
Terrain Category: C C ASCE 7-16, Table 7.3-1
Exposure of Roof: Fully Exposed Fully Exposed ASCE 7-16, Table 7.3-1
Exposure Factor, Ce: 0.9 0.9 ASCE 7-16, Table 7.3-1
Thermal Factor, Ct: 1.1 1.1 ASCE 7-16, Table 7.3-2
Risk Category: 11 II ASCE 7-16, Table 1.5-1
Importance Factor, Is: 1.0 1.0 ASCE 7-16, Table 1.5-2
Flat Roof Snow Load, pf [psf]: 35 35 ASCE 7-16, Equation 7.3-1
Minimum Roof Snow Load, pm [psf]: 0 0 ASCE 7-16, Section 7.3.4
Unobstructed Slippery Surface? No Yes ASCE 7-16, Section 7.4
Slope Factor Figure: Figure 7-2b Figure 7-2b ASCE 7-16, Section 7.4
Roof Slope Factor, Cs: 1.00 0.86 ASCE 7-16, Figure 7.4-1
Sloped Roof Snow Load, Ps [psf]: 35 30 ASCE 7-16, Equation 7.4-1
Design Snow Load, S [psf]: 35 30
Fbxx Fvxx g
Abbrev GRADES (psi) (psi) E.(psi) (lb/ft)
TORJOB NO.: U3507.0114.211 DFL#1 DFL#1 1,000 180 1,700,000 32
E I1 G I n E E R S DFL#2 DFL#2 900 180 1,600,000 32
DF1 (5X) DFL#1 5X5&LARGER 1,3501 170 1,600,000 32
SPF#2 SPF#2 875 135 1,400,000 26.2
SP#2 SP#2 1,100 175 1,400,000 34.3
PROJECT: Berger, Blair Residence Western Roof SUBJECT: BEAMS 24F-V4 24F-V4 2,400 240 1,800,000 32
24F-V8 24F-V8 2,400 240 1,800,000 40
LVL(1.9) LVL(1.9X106E) 2,6001 285 1,900,000 40
DESIGN LOADS: Load Types: Snow Live Dead LVL(2.0) LVL(2.OX106E) 2,200 285 2,000,000 42
Roof 50 20 5 CRITERIA(L/) DTL DLL DDL LSL LSL(1.3X106E) 1,700 400 1,300,000 42
Solar 3.2 A(BLANK) 120 180 STL36 GRADE 36 STEEL 21,600 14,400 29,000,000 490
STL46 IGRADE 46 STEEL 1 1 27,700 16,500 29,000,000 490
STL50 IGRADE 50 STEEL 1 1 30,0001 20,000 1 29,000,000 490
Point Point
0
Add'I Add'I Live Dead - n
Roof Floor Wall Live Solar Point �_ Dist Load Load 1.5DL
Length Trib Trib Trib Load Load Load ^y 'a' 'PLL' 'PDL �r = m Mmax Mallow Vmax Vallow DTL DTLallow DLL DLLallow GLB
Label L' (ft) I(ft) (ft) (ft) (plf) (plf) From oo I(ft) (lb) 1(lb) � Grade Size M y Cr JCD ICF,V Ra (lb) Rb (lb) (ft-lb) (ft-lb) (lb) (lb) (in) (in) (in) (in) Camb Check
Span [ft]: 12 Spacing [ft]: 1.333 Original is True Size? No
(E) Rafter 1 12.01 0.19 0.6 (1) ISPF#2 2x4 1.15 1.15 I1.50 71 71 213 I443 I453 543 0.736 I1.200 0.580 I0.800 I0.83 V
Sister 12.00 1.15 3.6 1 LVL 1.9 1-3/4X5-1/2 1.15 1.15 1.00 417 417 1252 2528 385 2103 0.704 1.200 0.580 0.800 0.73 D
JOB NO.: U3507.0114.211
TO R SUBJECT: LOAD COMPARISON
E n G I n E E R S
PROJECT: Berger, Blair Residence Eastern Roof
Summary of Loads
Existing With PV Array
D [psf] 9 12
Lr [psf] 20 0
S [psf] 35 30
Maximum Gravity Loads:
Existing With PV Array
(D+ Lr)/Cd [psf] 23 14 ASCE 7-16, Section 2.4.1
(D +S)/Cd [psf] 38 37 �ASCE 7-16, Section 2.4.1
(Cd=Load Duration Factor=0.9 for D,1.15 for S,and 1.25 for Lr)
Maximum Gravity Load [psf]:1 38 1 37
Ratio Proposed Loading to Current Loading: 1 96% OK
The gravity loads, and thus the stresses of the structural elements, in the area of the
solar array are either decreased or increased by no more than 5%.Therefore, the
requirements of Section 806.2 of the 2020 Minnesota Conservation Code for Existing
Buildings are met and the structure is permitted to remain unaltered.
JOB NO.: U3507.0114.211
YET O R SUBJECT: SOLAR LAYOUT
rl G I n E E R S
PROJECT: Berger, Blair Residence
a
r