HomeMy WebLinkAboutQuie Engineering Letter Flat Domus Domus Structural Engineering, LLC
�7 T R i) C T U R A 1, P.O. Box 560
Broomfield, CO 80038
�- N G 1 NEER TNG LLC 530-864-7055
projects@domusstruc.com
May 25,2023
To: Blue Raven Solar
1403 North Research Way,Building J
Orem,UT.84097
Subject: Certification Letter
Quie Flrsidence
1475 Creek Park Ln
Minneapolis,MN.55432
To Whom It May Concern,
Ajobsite observation of the condition of the existing framing system was performed by an audit team of Blue Raven Solar as a
request from Domus Structural Engineering.All review is based on these observations and the design criteria listed below and
only deemed valid if provided information istrue and accurate.
On the above referenced project,the roof structural framing has been reviewed for additional loading due to the installation of
the solar PV addition to the roof.The structural review only appliesto the section of the roof that isdirectly supporting the solar
PV system and itssupporting elements.The observed roof framing isdescribed below.If field conditions differ,contractor to
notify engineer prior to starting construction.
The roof structuresof(MP1&2)consist of composition shingle on roof plywood that issupported by pre-manufactured trusses
that are spaced at @ 24"o.c..The top chords,sloped at 23 degrees,are 2x4 sections,the bottom chords are 2x4 sections and the
web members are 2x4 sections.The truss members are connected by steel gusset plates.The max unsupported projected
horizontal top chord span is approximately 6-0".
The existing roof framing systems of(MPi&2)arejudged to be adequate to withstand the loading imposed by the installation of
the solar panels.No reinforcement is necessary.
The spacing of the solar standoffsshould be kept at 48"o.c.for landscape and 24"o.c.for portrait orientation,with a staggered
pattern to ensure proper distribution of loads.
The scope of this report is strictly limited to an evaluation of the fastener attachment,underlying framing and supporting
structure only.The attachment'sto the existing structure are required to be in a staggered pattern to ensure proper distribution
of loading.All panels,racking and hardware shall be installed per manufacturer specif ications and within specified design
limitations.All waterproofing shall be provided by the manufacturer. Domus Structural Engineering assumes no responsibility
for misuse or improper installation of the solar PV panels or racking.
Note:Seismic check is not required since Ss<.4g and Seismic Design Category(SDC)<B
Design Criteria:
• Applicable @odes=2020 Minnesota Building Code,ASCE7-16 ;`��•P,
• Fbof Dead Load=7 psf(M P1&2) :F '
• Fbof Live Load=20 psf 'ICEN D
• Wind Speed=115 mph(Vult),Exposure C _ I
• Ground Snow Load=50 psf - Roof Snow Load=35 psf = ENG E _
• Attachment:1 -5/16 dia.lag screw with 2.5 inch min.embedment -
depth,at spacing shown above. - 52823 A,��
'',�F '•••.. ... 1�50
Please contact me with any further questions or concerns regarding thisproject. ',,,OF •M114
Sincerely,
I hereby certify that this plan,specification or report was prepared by me Digitally signed by
or under my direct supervision and that I am a duly Licensed Professional John A.Calvert
Engineer under the laws of the State of Minnesota.John A.Calvert, Date:2023.05.25
.bhn Calvert,P.E. License No.52823 Expiration Date:30-June-2024
Project Engineer 17:10:49-06'00'
Quie Minneapolis MN 1
Do M u S Domus Structural Engineering, LLC
f`7 T R i) C T U R A 1, P.O. Box 560
Broomfield, CO 80038
�- N G 1 NEER TNG I. I. C. 530-864-7055
projects@domusstruc.com
Gravity Loading
Roof Snow Load Calculations
p9=Ground Snow Load= 50.0 psf
pf=0.7 CQ Ct I p9 (ASCE7-Eq 7-1)
CQ=Exposure Factor= 1 (ASCE7-Table 7-2)
Ct=Thermal Factor= 1 (ASCE7-Table 7-3)
1=Importance Factor= 1
pf=Flat Roof Snow Load= 35.0 psf
ps=Cspf (ASCE7-Eq 7-2)
Cs=Slope Factor= 1
ps=Sloped Roof Snow Load= 35.0 psf
PV Dead Load=3 psf(Per Blue Raven Solar)
DL Adjusted to 23 Degree Slope 3.26 psf
PV System Weight
Weight of PV System(Per Blue Raven Solar) 3.0 psf
X Standoff Spacing= 2.00 ff
Y Standoff Spacing= 6.08 ft
Standoff Tributary Area= 12.17 sft
Point Loads of Standoffs 37lb
Note:PV standoffs are staggered to ensure proper distribution of loading
Roof Live Load=20 psf
Note:Roof live load is removed in area's covered by PV array.
Roof Dead Load(MP1&2)
Composition Shingle 4.00
Roof Plywood 2.00
2x4 Top Chords @ 24"o.c. 0.73
Vaulted Ceiling 0.00 (Ceiling Not Vaulted)
Miscellaneous 0.27
Total Roof DL(MP1&2) 7.0 psf
DL Adjusted to 23 Degree Slope 7.6 psf
Quie Minneapolis MN 2
tom` O M u S Domus Structural Engineering, LLC
T R U C T U R A L P.O. Box 560
Broomfield, CO 80038
M N G I N E F. R T N C, T 1 C 530-864-7055
projects@domusstruc.com
Wind Calculations
Per ASCE7-16 Components and Gadding
Input Variables
Wind Speed 115 mph
Exposure Category C
Roof Shape Hip Roof
Roof Slope 23 degrees
Mean Roof Height 20 ft
Effective Wind Area 21.3 ft
Ground Elevation 0 ft
Design Wind Pressure Calculations
qh=0.00256'Kz'Kzt'Kd'Ke'VA2 (Eq.26.10-1)
Kz(Exposure Coefficient)=0.90 (Table 30.3-1)
Kzt(topographic factor)= 1.00 (Fig.26.8-1)
Kd(Wind Directionality Factor)= 0.85 (Table 26.6-1)
Ke(Ground Elevation Factor)= 1.00
V(Design Wind Speed)=115 mph (Fig.26.5-1A)
Risk Category=II (Table 1.5-1)
qh= 25.95
Standoff Uplift Calculations-Portrait
Zone 1 Zone 2 Zone 3 Positive
ya= 0.77 0.80 0.80 0.77
GCp= -1.35 -2.00 -2.00 0.67 (Fig.30.3)
Uplift Pressure= -27.0 psf -41.5 psf -41.5 psf 13.3 psf (Eq.29.4-7)
ASD Uplift Pressure= -16.2 psf -24.9 psf -24.9 psf 9.6 psf
X Standoff Spacing= 2.00 2.00 1.33
Y Standoff Spacing= 6.08 3.04166667 3.04166667
Tributary Area= 12.17 6.08 4.06
Dead Load on attachment= 37lb 18 lb 12 lb
Footing Uplift(0.613+0.6W)_ -175lb -141 lb -94lb
Standoff Uplift Calculations-Landscape AN
Zone 1 Zone 2 Zone 3 Positive
ya= 0.75 0.80 0.80 0.75
GCp= -1.31 -2.00 -2.00 0.64 (Fig.30.3)
Uplift Pressure= -25.6 psf -41.5 psf -41.5 psf 12.5 psf (Eq.29.4-7)
ASD Uplift Pressure(0.6W)= -15.3 psf -24.9 psf -24.9 psf 9.6 psf
X Standoff Spacing= 4.00 4.00 2.67
Y Standoff Spacing= 3.50 1.75 1.75
Tributary Area= 14.00 7.00 4.67
Dead Load on attachment= 42.00 21.00 14.00
Footing Uplift(0.6D+0.6W)_ -190 lb -162lb -108lb
Standoff Uplift Check
Maximum Design Uplift=-190 lb
Standoff Uplift Capacity =450 lb
450 lb capacity>190 lb demand Therefore,OK
- Fastener Capacity Check
Fastener=1-5/16"dia.lag
Number of Fasteners=1
Embedment Depth=2.5
Pullout Capacity Per Inch= 250 lb
Fastener Capacity=625 lb
w/F.S.of 1.5&DOL of 1.6=667lb
667.2 lb capacity>190 lb demand Therefore,OK
Quie Minneapolis MN 3
Do M u S Domus Structural Engineering, LLC
T R 1) C T LJ R A 1, P.O. Box 560
Broomfield, CO 80038
- N G 1 N E E R i lei G T i. C' 530-864-7055
projects@domusstruc.com
Framing Check
(MP1&2)
w=92 plf
Dead Load 7.6 psf
PV Load 3.3 psf
Snow Load 35.0 psf 2x4 Top Chords @ 24"o.c.
16s, O
Governing Load Combo=DL+SL Member Span=6'-0"
Total Load 45.9 psf
Member Properties
Member Size S(in^3) I(in^4) Lumber Sp/Gr Member Spacing
2x4 3.06 5.36 DF#2 @ 24"o.c.
Check Bending Stress
Fb(psi)= f'b x Cd x Cf x Cr (NDS Table 4.3.1)
900 x 1.15 x 1.5 x 1.15
Allowed Bending Stress=1785.3 psi
Maximum Moment = (wL^2)/8
=412.7724 ft#
=4953.269 in#
Actual Bending Stress=(Maximum Moment)/S
=1617.4 psi
Allowed>Actual--90.61%Stressed -- Therefore,OK
Check Deflection
Allowed Deflection(Total Load) = U180 (E=1600000 psi Per NDS)
=0.4 in
Deflection Criteria Based on = Continuous Span
Actual Deflection(Total Load) _ (w*L^4)/(185*E*I)
=0.130 in
= U554 > L/180 Therefore OK
Allowed Deflection(Live Load) = U240
0.3 in
Actual Deflection(Live Load) _ (w*L^4)/(185*E*I)
0.099 in
U728 > L/240 Therefore OK
Check Shear
Member Area=5.3 in^2 Fv(psi)= 180 psi (NDS Table 4A)
Allowed Shear = Fv*A = 945 lb Max Shear(V)=w*L/2 = 275 lb
Allowed>Actual--29.21%Stressed -- Therefore,OK
Quie Minneapolis MN 4
Domus Domus Structural Engineering, LLC
TRUCTURAL P.O. Box560
-_ N G 1 NEER i N G 1. 1. C Broomfield, CO 80038
530-864-7055
projects@domusstruc.com
Appendix A:General Notes
GENERAL
• The contractor shall verify all dimensions,property setbacks,AHJ/HOA CC&R's,elevations and site conditions before
starting work and shall notify Domus Structural Engineering,LLC of any discrepancies.
• All report conclusions represent Domus Structural Engineering,LLC's best professional judgment based upon industry
standards.
• Resolve any conflicts on the drawings with Domus Structural Engineering,LLC before proceeding with construction.
• The design criteria used for this project&listed on the first page of the report is based on the engineers best judgement
and/or provided by the ATC council.AHJ specific requests may differ.Please contact our team if the design criteria needs to
be modified.
• A site visit was not physically conducted by Domus Structural Engineering,LLC.The accompanying calculations and
certification are provided with the understanding that the site building and construction standards meet an acceptable level of
industry standards.It shall be the contractors responsibility to identify any irregularities such as inconsistent framing
conditions,water damage,fire damage,cracked,split or noticeably deflecting framing members.
• Domus Structural Engineering,LLC is not responsible for enforcing safety measures or regulations.The contractor shall
design,construct,and maintain all safety devices including shoring and bracing,and shall be solely responsible for
conforming to all local,state and federal safety and health standards,laws and regulations.The contractor shall take
necessary precautions to maintain and insure the integrity of the structure during construction.If a lawsuit is filed by one of
the contractor's or subcontractor's employees,or any one else,the contractor will indemnify,defend and hold the owner and
Domus Structural Engineering,LLC harmless of any and all such claims.
• Any and all waterproofing shall be provided by the contractor.Domus Structural Engineering,LLC is not responsible for
waterproofing.
• All hardware shall be installed per manufacturer specifications and within specified design limitations.Domus Structural
Engineering,LLC assumes no responsibility for incorrectly installed hardware or hardware installed outside of the
manfacturer specifications.
USER RELIANCE
• Domus Structural Engineering,LLC was engaged by Blue Raven Solar(Client)to perform this assessment.This report and
the information therein,are for the exclusive use of the Client.This report has no other purpose and shall not be relied upon,
or used,by any other person or entity without the written consent of Dous Structural Engineering,LLC.Third parties that
obtain this report,or the information within shall have no rights of recourse or recovery against Domus Structural
Engineering,LLC,it's officers or employees.
ROOF MOUNTED ARRAYS
• If an analysis of a supporting stucture is included in our scope of work,the structural assessment only applies to the section
of the roof that is directly supporting the proposed solar PV system.
• No structural members can be cut for conduit,etc.,unless specifically shown.Obtain prior written approval for installation of
any additional conduit,etc.
• It is assumed that a standard quality of construction care was used to construct the original building.It shall be the
contractors responsibility to field verify any and all framing member supporting the proposed PV array are in adequate
condition.The contractor shall field inspect for sub-standard construction means,signs of dry rot,mold,fire damage,etc.and
notify engineer if any compromised material is found on site prior to starting construction.
• It is assumed that there have been no additional loads(HVAC or MEP equipment,additional layers of roofing,etc)added to
the building over the course of the structures histroy.The contractor and/or client shall verify this with the property owner and
notify Domus Structural Engineering,LLC if additional load has been added to the structure already.
• Flexible utility connections must be used at any building seismic joint.
• Care should be taken to ensure that PV arrays do not preclude drainage of rain water.
• Unless otherwise noted,construction material shall be evenly distributed if placed on framed floors or roofs.Loads shall not
exceed the allowable loading for the supporting members and their connections.
• All lags or wood screws at the roof shall be stainless steel and installed withing the middle 1/3 of the dimensional width of the
framing members.
• All fasteners shall be a minimum of 6"away from any truss panel or hinge joints,truss plates and/or member ends.Field
verify location of fasteners prior to starting construction.All fasteners shall be pre-drilled to avoid splitting existing lumber.
• Domus Structural Engineering,LLC is not responsible for downslope effects of snow shedding or sliding off of the PV array
nor any damage to downslope decks,roofs,walkways,landscaping,automobiles,pets,people,etc..If snow guards are
requested by the customer,notify Domus Structural Engineering,LLC.
Quie Minneapolis MN 5