asce wind load examples.pdf
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Wind Loads for Solid Signs,
Other Structures, Roof-TopStructures & Equipment, and
Other Special ConditionsBo !aullus, !"E", S"E"
!aullus Structural Consultants
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#" #" Chapter $% Other Structures '(W)RS
*irectional (ethod+a" Conditions
" Limitationsc" Solid )reestanding Walls or Signs
d" Solid ttached Signs
e" *esign Wind Loads on Other Structures
f" *esign Wind Loads on Rooftop Structures
and Equipment on Buildings
g" !arapets
h" Roof Oerhangs
i" (inimum *esign Wind Loadings
Outline
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#" $" Chapter ./ !art 0 - Components &
Cladding for Building ppurtenances
and Rooftop Structures and Equipment
'*irectional !rocedure+a" !arapets
" Roof Oerhangs
c" Rooftop Structures and Equipment for
Buildings 1ith h 2 0/ ft '#3". m+$" ." E4amples
Outline
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5 #" The structure is a regular-shaped
structure as defined in Section $0"$"$"
Section 26.2.2 - BUILDING OR OTHER
STRUCTURE, REGULAR-SHAPED:
uilding or other structure haing no
unusual geometrical irregularit6 in spatialform"
Section $%"#"$ - Conditions
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5 $" The structure does not hae response
characteristics ma7ing it su8ect to across-
1ind loading, orte4 shedding, or instailit6
due to galloping or flutter9 or it does not
hae a site location for 1hich channeling
effects or uffeting in the 1a7e of up1ind
ostructions 1arrant special consideration"
Section $%"#"$ - Conditions
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5 #" This chapter *OES consider: load
magnification effect caused 6 gusts in
resonance 1ith along-1ind irations of
fle4ile structures"
5 $" This chapter *OES ;OT consider:
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5 ." =f 6our structure does not fall 1ithin the
listed limitations, it should proal6 e the
su8ect of Wind Tunnel Stud6"
Section $%"#". Limitations
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5 #" ;o reductions allo1ed for apparent
shielding 6 uildings, other structures, or
terrain features"
a" =ndiidual hills
" =ndiidual trees or small groes of
trees
c" =ndiidual leees and similar
features"
5 $" Reductions are afforded for Terrain
)eatures in determining E4posure
Categories in Chapter $0"
Section $%"#"> Shielding
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Steps
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5 #" Steps #-> are the same as in Chapters
$0-./"a" Chapter $%, li7e Chapters $0-./, has its
o1n tale, Tale $%".-#, for ?h and ?@" Step A: Eq" $%".-#
q@ /"//$A0?@?@t?d$ 'lDft$+
5 $" Be careful to use q@ or qh, as directedunder each section"
Steps to *etermine Wind Loads
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5 #" ollo1 Signs and Walls are not coered"
a" Signs 1hich hae openings that can epressuri@ed
#+ Bo4ed signs
$+ Signs made from sea containers
.+ Signs 1ith large internal areas for lights
1ith translucent panels
$" Research is eing conducted at Te4asTech
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5 ." Solid Signs can hae openings up to
./F of the Gross rea"
a" Reduction factor can e applied to solidsigns 1ith openings"
" Reduction factor '# - '# - H+#"A+
c" H ratio of solid area to gross area
>" =f the area of openings e4ceeds ./F of
the gross area, it is an open sign" !roceed to Section $%"A - *esign Wind
LoadsIOther Structures
Section $%">"# Solid )reestanding Walls
and Solid )reestanding Signs
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5 A" Basic Equation: 'Eq" $%">-#+
) qhGCfs 'l+5 a" qh the elocit6 pressure ealuated at
height h 'defined in )ig" $%">-#+ as
determined in accordance 1ith
Section $%"."$
h top of the 1all or sign
;ote: qh
is at the top of the sign or 1all
and ?d in Eq $%".-# is the ?d of Solid
)reestanding Walls and Solid )ree-
standing and ttached Signs in Tale
$0"0-#
Section $%">"# Solid )reestanding Walls
and Solid )reestanding Signs
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5 " G gust-effect factor from Section $0"%
c" Cf net force coefficient from )ig" $%">-#
d" s the gross area of the solid free-
standing 1all or freestanding solid sign, in
ft$ 'm$+
Section $%">"# Solid )reestanding Walls
and Solid )reestanding Signs
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)igure $%">-#
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)igure $%">-#
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)igure $%">-#
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5 Load Cases to Consider
Case Load applied to the centroid of
the area Case B Load applied 1ith an
eccentricit6 of /"$JB '1idth of the 1all or
sign+
Case C Stepped application of reduced1ind pressures as the distance decreases
from the 1ind1ard edge"
Section $%">"# Solid )reestanding Walls
and Solid )reestanding Signs
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Case C
Reduction in loads for 1alls or signs 1ith
returns at the ends
/ F reduction
)or Eleated Signs or 1alls: 1here sDh K /"3,
force coefficients shall e multiplied 6 the
reduction factor '#"3 - sDh+
ccounts for reduced 1ind pressures1hen free air flo1 under the 1all or sign
is reduced"
Section $%">"# Solid )reestanding Walls
and Solid )reestanding Signs
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Section $%">"# Solid )reestanding Walls
and Solid )reestanding Signs
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a"#" Requirements to use method in Section
$%">"#
a" The plane of the sign is parallel to and incontact 1ith the supporting 1all
" Edges of the sign do not e4tend past the
supporting 1all
c" "# $ - Solid ttached Signs
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a" $" !rocedure can also e used for
signs attached to ut not in contact
1ith the supporting 1all"
a" Sign must e parallel to the supporting 1all"" Sign must not e more than three '.+ feet
from the 1all"
c" Edges of the sign must e at least '.+ feet in
from the free edges of the supporting 1all:a" Top of the supporting 1all"
" Bottom of the supporting 1all
c" Side Edges of the supporting 1all
Section $%">"# $ - Solid ttached Signs
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Section $%"A: *esign Wind LoadsIOther
Structures
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Basic Equation: 'Eq" $%"A-#+
) q@GCff'l+ ';+
a" q@ elocit6 pressure ealuated at height @ as
defined in Section $%"., of the centroid of area f
;ote q@ is at the centroid of the area and ?d in
Eq $%".-# is the ?d of the structure t6pe in
Tale $0"0-#
" G gust-effect factor from Section $0"% 'these
structures ma6 often e fle4ile+
c" Cf force coefficients from )igs" $%"A-#
Section $%"A: *esign Wind LoadsIOther
Structures
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d" f pro8ected area normal to the 1ind e4cept
1here Cfis specified for the actual surface area,
in ft$ 'm$+
Section $%"A: *esign Wind LoadsIOther
Structures
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)igure $%"A-#
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)igure $%"A-#
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)igure $%"A-$
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)igure $%"A-$
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)igure $%"A-.
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)igure $%"A-.
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#" ;o guidance is gien for rooftop
structures on uildings K 0/ feet"
$" Research in the SCE committee
suggests that it is proal6 acceptale to
use loads from this section for rooftop
structures on uildings K 0/ feet, ut this
has not een confirmed 6et"." Equation $%"A-$ gies lateral pressure
on the rooftop structure"
Section $%"A-# Rooftop Structures and
Equipment )or Buildings 1ith h 0/ feet
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Lateral Wind force on Rooftop Structures
Basic Equation: 'Eq $%"A-$+
)h qh'GCr+f'l+ ';+
'GCr+ #"% for rooftop structures and
equipment 1ith fless than '/"#Bh+" 'GCr+
shall e permitted to e reduced linearl6
from #"% to #"/ as the alue of fis
increased from '/"#Bh+ to 'Bh+"
qh elocit6 pressure ealuated at mean
roof height of the uilding
Section $%"A-# Rooftop Structures and
Equipment )or Buildings 1ith h 2 0/ feet
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Lateral Wind force on Rooftop Structures
;ote, qh is at the mean roof height and ?d
in Eq $%".-# is the ?d of the uilding, in
Tale $0"0-#, on 1hich the rooftop
structure sits"
f ertical pro8ected area of the rooftop
structure or equipment on a plane normal
to the direction of 1ind, in ft$ 'm$+
Section $%"A-# Rooftop Structures and
Equipment )or Buildings 1ith h 2 0/ feet
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ertical Wind force on Rooftop Structures
Basic Equation: 'Eq $%"A-.+
) qh'GCr+r 'l+ ';+
'GCr+ #"A for rooftop structures and
equipment 1ith r less than '/"#BL+" 'GCr+
shall e permitted to e reduced linearl6
from #"A to #"/ as the alue of r is
increased from '/"#BL+ to 'BL+" qh elocit6 pressure ealuated at mean
roof height of the uilding
Section $%"A-# Rooftop Structures and
Equipment )or Buildings 1ith h 2 0/ feet
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ertical Wind force on Rooftop Structures
;ote qh is at the mean roof height and ?d in
Eq $%".-# is the ?d of the uilding, in Tale
$0"0-#, on 1hich the rooftop structure sits"
r hori@ontal pro8ected area of rooftop
structure or equipment, in ft$ 'm$+
Section $%"A-# Rooftop Structures and
Equipment )or Buildings 1ith h 2 0/ feet
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Lateral C & C pressure 'psf+ shall e equal
to the lateral force 'Ls+ calculated 1ith
equation '$%"A-$+ *==*E* BM the
RES!ECT=E WLL Surface area of the
Rooftop Structure considered"
)orces 'psf+ shall e considered to act in1ard
and out1ard
Section ./"## Component & Cladding
Loads for Rooftop Structures and
Equipment for Buildings 1ith h 2 0/ feet
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ertical C & C pressure 'Ls+ shall e
equal to the ertical force 'Ls+ calculated
1ith equation '$%"A-.+ *==*E* BM the
ori@ontal pro8ected area of the roof of
the Rooftop Structure considered"
The pressures are O;LM required to econsidered to act in the
Loads for Rooftop Structures and
Equipment for Buildings 1ith h 2 0/ feet
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Comment: =f the Rooftop Structure is
large '#/N4$/N or larger+, consider loo7ing
at the do1n1ard pressures from the
uilding C&C loading figures and ma7e
some 8udgment aout do1n1ard 1ind
loading rooftop structures that resemle
small uildings 'penthouses for instance+" ertical Wind Load 1ould act in addition to
*ead and Roof Lie Loads or Sno1 Loads"
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Other Resources
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Other Resources5 !repared 6: Tas7
Committee on Wind-
=nduced )orces of the
!etrochemical Committee
of the Enginer6 *iision ofSCE
5 Seeral of those on the
Tas7 Committee are on
the SCE Wind
Sucommittee
5 Based on SCE -/A
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Wind loads on parapets are specified in
Section $">"A for uildings of all heights
designed using the *irectional !rocedure
and in Section $3">"$ for lo1-rise
uildings designed using the Enelope
!rocedure"P
(ethod presented is the *irectional!rocedure
Section $%"0 !arapets '(W)RS+
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Chapter $3 The Enelope (ethod, is
e4actl6 the same"
Chapter $3 uses the elocit6 pressure
determined 1ith the Enelope (ethod,
rather than the elocit6 pressure in Chapter
$ using the *irectional (ethod"
Section $%"0 !arapets '(W)RS+
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(W)RS pressures due to parapets
Rigid or )le4ile Buildings
pplies to )lat, Gale, or ip Roofs
Section $">"A - !arapets
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Basic Equation: 'Eq $">->+
pp qp'GCpn+ 'lDft$+
pp comined net pressure on the parapet
due to the comination of the net pressures
from the front and ac7 parapet surfaces"
!lus 'and minus+ signs signif6 net pressure
acting to1ard 'and a1a6 from+ the front
'e4terior+ side of the parapet
Section $">"A !arapets '(W)RS+
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qp elocit6 pressure ealuated at the top of
the parapet
'GCpn+ comined net pressure
coefficient Q#"A for 1ind1ard parapet
#"/ for lee1ard parapet
Section $">"A !arapets '(W)RS+
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Section $">"A !arapets '(W)RS+ )=G
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pplicale to ll Building T6pes
pplicale to ll Building eights
E4cept Where the !roisions of !art >
are used 'Simplified (ethod for
Buildings 1ith h 2 #0/ feet+
Section ./"% C & C Loading on !arapets
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Basic Equation: 'Eq" ./"%-#+
p qp''GCp+ 'GCpi++
qp elocit6 pressure ealuated at the top of
the parapet
'GCp+ e4ternal pressure coefficient gien in
)ig" ./">-# for 1alls 1ith h 2 0/ ft '>3"3 m+
)igs" ./">-$ to ./">-$C for flat roofs,
gale roofs, and hip roofs
)ig" ./">-. for stepped roofs
Section ./"% C & C Loading on !arapets
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'GCp+ e4ternal pressure coefficient gien in
)ig" ./">-> for multispan gale roofs
)igs" ./">-A and ./-AB for monoslope
roofs )ig" ./">-0 for sa1tooth roofs
)ig" ./">- for domed roofs of all heights
)ig" ./"0-# for 1alls and flat roofs 1ith h K
0/ ft '#3". m+ )ig" $">-. footnote > for arched roofs
Section ./"% C & C Loading on !arapets
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'GCpi+ internal pressure coefficient from
Tale $0"##-#, ased on the porosit6 of the
parapet enelope"
Consider T1o '$+ Load Cases 1hen
ealuating C & C pressures on parapets
Case !ressures on the surfaces of the
Wind1ard parapet
Case B !ressures on the surfaces of the
Lee1ard parapet
Section ./"% C & C Loading on !arapets
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Specifics of Case :
Wind1ard !arapet shall consist of appl6ing the
applicale positie 1all pressure from )ig" ./">-#
'h 2 0/ ft '#3". m++ or )ig" ./"0-# 'h K 0/ ft '#3".m++ to the 1ind1ard surface of the parapet 1hile
appl6ing the applicale negatie edge or corner
@one roof pressure from )igs" ./">-$ ', B or C+,
./">-., ./">->, ./">-A ' or B+, ./">-0, ./">-, )ig"
$">-. footnote >, or )ig" ./"0-# 'h K 0/ ft '#3".
m++ as applicale to the lee1ard surface of the
parapet"
Section ./"% C & C Loading on !arapets
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Specifics of Case B:
Lee1ard !arapet shall consist of appl6ing the
applicale positie 1all pressure from )ig" ./">-#
'h 2 0/ ft '#3". m++ or )ig" ./"0-# 'h K 0/ ft '#3".m++ to the 1ind1ard surface of the parapet, and
appl6ing the applicale negatie 1all pressure
from )ig" ./">-# 'h 2 0/ ft '#3". m++ or )ig" ./"0-#
'h K 0/ ft '#3". m++ as applicale to the lee1ard
surface" Edge and corner @ones shall e arranged
as sho1n in the applicale figures" 'GCp+
Section ./"% C & C Loading on !arapets
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Section ./"% C & C Loading on !arapets )=G
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Step #: *etermine ris7 categor6 of uilding,
see Tale #"A-#
Step $: *etermine the asic 1ind speed, ,
for applicale ris7 categor6, see )igure $0"A-
#, B or C
Tale ./"%-# Steps to *etermine C&C
Wind Loads on !arapets
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Step .: *etermine 1ind load parameters:
Wind directionalit6 factor, ?d , see Section $0"0
and Tale $0"0-#
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Step >: *etermine elocit6 pressure
e4posure coefficient, ?h, at top of the
parapet see Tale ./".-#
Step A: *etermine elocit6 pressure, qp, at
the top of the parapet using Eq" ./".-#
Tale ./"%-# Steps to *etermine C&C
Wind Loads on !arapets
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Step 0: *etermine e4ternal pressure
coefficient for 1all and roof surfaces
ad8acent to parapet, 'GCp+
Walls 1ith h 2 0/ ft", see )ig" ./">-#
)lat, gale and hip roofs, see )igs" ./">-$ to
./">-$C
Stepped roofs, see )ig" ./">-.
(ultispan gale roofs, see )ig" ./">->
(onoslope roofs, see )igs" ./">-A and ./">-AB
Sa1tooth roofs, see )ig" ./">-0
Tale ./"%-# Steps to *etermine C&C
Wind Loads on !arapets
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Step 0: 'Continued+
*omed roofs of all heights, see )ig" ./">-
Walls and flat roofs 1ith h K 0/ ft", see )ig" ./"0-#
rched roofs, see footnote > of )ig" $">-.
Step : Calculate 1ind pressure, p, using Eq"
./"%-# on 1ind1ard and lee1ard face of
parapet, considering t1o load cases 'Case
and Case B+ as sho1n in )ig" ./"%-#"
Tale ./"%-# Steps to *etermine C&C
Wind Loads on !arapets
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Section ./"% C & C Loading on !arapets
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)igure ./"0-#
5 ;ote defines parapets K . feet as tall
parapets Reduced corner pressures on parapet
Similar note on other figures
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Wind loads on roof oerhangs are
specified in Section $">"> for uildings of
all heights designed using the *irectional
!rocedure and in Section $3">". for lo1-
rise uildings designed using the Enelope
!rocedure"P
!resent *irection (ethod in Section $">"# Enelope (ethod in Section $3"."# is similar
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The positie e4ternal pressure on the
ottom surface of 1ind1ard roof
oerhangs shall e determined using Cp
/"3 and comined 1ith the top surface
pressures determined using )ig" $">-#"
Section $"> Roof Oerhangs '(W)RS+
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Section $"> Roof Oerhangs '(W)RS+
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Section $"> Roof Oerhangs '(W)RS+
(ust consider cases 1ith positie internal
pressure and negatie internal pressure
)rom )igure $"0-.
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Section ./"#/ C & C Loading on Roof
Oerhangs pplicale to ll Building T6pes
pplicale to ll Building eights
E4cept Where the !roisions of !art >
are used 'Simplified (ethod for
Buildings 1ith h 2 #0/ feet+
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Section ./"#/ C & C Loading on Roof
Oerhangs Basic Equation: 'Eq" ./"#/-#+
p qh''GCp+ 'GCpi++
qh elocit6 pressure from Section ./"."$
ealuated at mean roof height h using
e4posure defined in Section $0"".
'GCp+ e4ternal pressure coefficients for
oerhangs gien in )igs" ./">-$ to ./">-$C
'flat roofs, gale roofs, and hip roofs+,
including contriutions from top and ottom
surfaces of oerhang"
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Section ./"#/ C & C Loading on Roof
Oerhangs The e4ternal pressure coefficient for the
coering on the underside of the roof
oerhang is the same as the e4ternal
pressure coefficient on the ad8acent 1allsurface, ad8usted for effectie 1ind area,
determined from )igure ./">-# or )igure
./"0-# as applicale
'GCpi+ internal pressure coefficientgien in Tale $0"##-#
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)igure ./">-$
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)igure ./">-#
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Step #: *etermine ris7 categor6 of uilding,
see Tale #"A-#
Step $: *etermine the asic 1ind speed, ,
for applicale ris7 categor6, see )igure $0"A-
#, B or C
Tale ./"#/-# Steps to *etermine C&C
Wind Loads on Roof Oerhangs
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Step .: *etermine 1ind load parameters:
Wind directionalit6 factor, ?d , see Section $0"0
and Tale $0"0-#
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Step >: *etermine elocit6 pressure
e4posure coefficient, ?h, see Tale ./".-#
Step A: *etermine elocit6 pressure, qh, at
mean roof height h using Eq" ./".-#
Tale ./"#/-# Steps to *etermine C&C
Wind Loads on Roof Oerhangs
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Step 0: *etermine e4ternal pressure
coefficient, 'GCp+, using )igs" ./">-$
through C for flat, galed and hip roofs"
Step : Calculate 1ind pressure, p, using Eq"
./"#/-#" Refer to )igure ./"#/-#
Tale ./"#/-# Steps to *etermine C&C
Wind Loads on Roof Oerhangs
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)igure ./"#/-#
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The design 1ind force for other structures
shall e not less than #0 lDft$ '/" 7;Dm$+
multiplied 6 the area f"
#0 psf is #/ psf from SCE -/A times #"0 to ring
the load to a strength leel load"
ppl6 to the full pro8ected area in each
orthogonal direction"
Section $%"3 (inimum *esign Wind
Loading '(W)RS+
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Loads on man6 shapes in industrial plants
Tan7s, Silos, !ipe rac7s, !artiall6 Clad
)rames, etc"
See SCE report: Wind Loads for
!etrochemical and Other =ndustrial
)acilitiesP
Wind Loads on roof mounted Solar!hotooltaic rra6s
See ne1 SEOC Guide
(aterial in Chapters $% ;ot Coered
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Other Ressources
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5 Office Com!e"
Loc#tion: $ic%it#, &S
'(ee)t#n*in+ Si+n
-Sto( Office
-foot t#!! #(#et
Roof To Unit
$e!! P/m 0 1#inten#nce B/i!*in+Roof Oe(%#n+
C%emic#! Sto(#+e Si!o
E4ample
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5 Site P#(#mete() Common to A!! E"#m!e)
E"o)/(e 3Te((#in Ro/+%ne))4: C Loc#tion: N 5.5, $ 75.869
Section 26.5. 3Oen '#(m!#n*4
Ri) C#te+o( II St(/ct/(e) T#;!e 8.-8
$in*
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E4ample
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5 So!i* Bi!!;o#(* Si+n #t G(o/n* Lee! Dimen)ion): @ $i*e " 8@ Hi+%
Refe(ence 'i+/(e 27.-8 31$'RS4
)8@
B@
%8@
&% .9 3T#;!e 27.-84
&* .9 3So!i* '(ee)t#n*in+ $#!!) 0 Si+n)43T#;!e 26.6-84
% .26 &?&?t&*%e(e )=% F .9, Cf m# ;e m/!ti!ie* ; t%e
(e*/ction f#cto( 38.9 )=%4
)=% 8. F .9
38.9 )=%4 38.9 8.4 .9
' %GCfA) 3L;4 3E 27.-84 '8 32.6)f43.9432.643.9438@"8@4 2 L;)
'2 32.6)f43.9438.543.9438@"8@4 2929 L;)
' 32.6)f43.9438.843.9438@"8@4 878 L;)
A! '8, '2, #n* ' #t !#n C.L. of e#c% !#n !en+t%, ),
f(om e#c% en* of )i+n. See 'i+/(e. A! '8, '2 #n* ' #t .@ #;oe ;#)e of e#c% !#n
!en+t%, )
E4ample-)reestanding Sign
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E4ample-)reestanding Sign
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5 P#(#et 31$'RS4 3Section 27.64
Office B/i!*in+ L 2 ft., B 8 ft.
Roof Hei+%t: % ft. P#(#et Hei+%t: % ft.
Roof S!oe, '!#t: .2:82
Ri*+e #(#!!e! to 2@ )i*e
E"o)/(e C#te+o(: C
Section 27.6 (efe(ence) Section 25.. fo(*i(ection#! (oce*/(e fo( 1$'RS P#(#et !o#*
*ete(min#tion.
E4ample-!arapet '(W)RS+
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3GCn4 3)f4
.26&%&?t&*in*>#(* #(#et 3Section 25..4
GCn -8. fo( !ee>#(* #(#et 3Section 25..4
$in*>#(* P#(#et
3.6 )f438.4 .79 )f #ctin+ to>#(* ;/i!*in+
Lee>#(* P#(#et
3.6 )f43-8.4 -.6 )f #ctin+ #># f(om
;/i!*in+
E4ample-!arapet '(W)RS+
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5 P#(#et 3C 0 C Lo#*)4 3Section .74
Office B/i!*in+ )#me #) (eio/)
.2638.6438.43.9438842 .6 )f
f(om #(#et 1$'RS, #;oe 33GC4 3GCi44 3E .7-84
P#(#et c#n ;e (e))/(i?e* #!on+ >it% ;/i!*in+
See 'i+/(e
GCi .89 3Enc!o)e* B/i!*in+ T#;!e 26.88-84
E4ample-!arapet 'C & C+
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E4ample-!arapet 'C & C+
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St/*) 86J o.c. 3;ot% f#ce)4
Dete(mine Effectie $in* A(e# of St/*)
G(e#te( of T(i;/t#( A(e# o( Effectie $i*t%
Effectie $in* A(e# Definition 3Section 26.24
G(e#te( of 86J=82J 8.@ o( Len+t%= @= 8.65@ 3+oe(n)4
Effectie $in* A(e#: l2= 2= 9. ft2
If Effectie $in* A(e# F 5 ft2, /)e 1'$RS !o#*)
Dete(mine >%ic% fi+/(e to (efe(ence f(om T#;!e .7-8,
Ste 6 'i+/(e .-8 fo( >#!! (e))/(e), % K 6 ft.
E4ample-!arapet 'C & C+
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'i+/(e .-2A fo( (oof !o#*), % K 6 ft. #n* +#;!e (oof)
K 5
Dete(mine M#J *i)t#nce 3'i+/(e .-8 #n* .-2A4
Le))e( of 8 of B .838@4 8@ #n* .%
.3@4 86@
8@ +oe(n)
Not !e)) t%#n t%e +(e#te( of of B .38@4 @
o( @
# 8@
Ente(in+ 'i+/(e .-8 fo( (e))/(e coefficient) on
e"te(io( )/(f#ce) of t%e #(#et):
one Po)itie P(e))/(e: GC 8.
one Po)itie P(e))/(e: GC 8.
E4ample-!arapet 'C & C+
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one Ne+#tie P(e))/(e: GC -8.8
one Ne+#tie P(e))/(e: GC -8.
Note )#) t%#t #!/e) of GC m# ;e (e*/ce*
; 8 >%en K 8
one Po)itie P(e))/(e: GC 3.748. .7 one Po)itie P(e))/(e: GC 3.748. .7 one
Ne+#tie P(e))/(e: GC 3.74-8.8 -8.
one Ne+#tie P(e))/(e: GC 3.74-8. -8.26
Ente(in+ 'i+/(e .-2A fo( (e))/(e coefficient) on
inte(io( 3(oof )i*e4 )/(f#ce) of #(#et:
Effectie $in* A(e#: A 2= 9. ft2
# 8 ft. #) in 'i+/(e .-8
one 8, 2, #n* Po)itie P(e))/(e: GC .
E4ample-!arapet 'C & C+
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one 8 Ne+#tie P(e))/(e: GC -8.
one 2 Ne+#tie P(e))/(e: GC -8.9
one Ne+#tie P(e))/(e: GC -2.9
Note : MIf # #(#et e/#! to o( %i+%e( t%#n ft
3.7m4 i) (oi*e* #(o/n* t%e e(imete( of t%e
(oof >it% K 5, t%e ne+#tie #!/e) of GC in
one )%#!! ;e e/#! to t%o)e fo( one 2 #n*
o)itie #!/e) of GC in one) 2 #n* )%#!! ;e
)et e/#! to t%o)e fo( >#!! one) #n*
(e)ectie! in 'i+/(e .-8.J
P#(#et %ei+%t % @ F @ one Ne+#tie GC i) Not A!ic#;!e
one 2 #n* one Po)itie P(e))/(e GC #(e
t%o)e of $#!! one #n* one , (e)ectie!.
E4ample-!arapet 'C & C+
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Ste 5: C#!c/!#te >in* (e))/(e, /)in+ E .7-8 on
>in*>#(* #n* !ee>#(* f#ce) of #(#et, con)i*e(in+ t>o
!o#* c#)e) 3CASE A #n* CASE B4 #) )%o>n in 'i+/(e .7-8
Note: A) >in* *i(ection c%#n+e), e#c% #(#et >it% )%ift
f(om # >in*>#(* #(#et to # !ee>#(* #(#et.
CASE A $in*>#(* P#(#et E"te(io( '#ce $#!! St/*)
33GC4 3GCi44 3E .7-84
$it% Po)itie Inte(n#! P(e))/(e
one one
P 3.6 )f433.74-3.8944 22.6 )f
$it% Ne+#tie Inte(n#! P(e))/(e
one one
3.6 )f433.74-3-.8944 .8 )f
E4ample-!arapet 'C & C+
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A! to T(i;/t#( A(e#, not Effectie $in* A(e#
.8 )f38.@4 .82 !f
Inte(io( '#ce 3(oof )i*e4 P#(#et St/*)
33GC4 3GCi44 3E .7-84
$it% Po)itie Inte(n#! P(e))/(e one 2 3one #!)o t(e#te* #) one 24
3.6 )f433-8.94-3.8944 -6.67 )f
$it% Ne+#tie Inte(n#! P(e))/(e
one 2 3one #!)o t(e#te* #) one 24
3.6 )f433-8.94-3-.8944 -.6 )f
A! to T(i;/t#( A(e#, not Effectie $in* A(e#
-6.67 )f38.@4 -9.52 !f
E4ample-!arapet 'C & C+
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CASE B Lee>#(* P#(#et
Inte(io( '#ce P#(#et St/*) 3!o#* to>#(* #(#et4
33GC4 3GCi44 3E .7-84
$it% Po)itie Inte(n#! P(e))/(e
S/;)tit/te one #n* one (e))/(e) fo( (oofone 2 #n* one (e))/(e), (e)ectie!. one
one
P 3.6 )f433.74-3.8944 22.6 )f
$it% Ne+#tie Inte(n#! P(e))/(e
one one
3.6 )f433.74-3-.8944 .8 )f
A! to T(i;/t#( A(e#, not Effectie $in* A(e#
.8 )f38.@4 .82 !f
E4ample-!arapet 'C & C+
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E"te(io( '#ce $#!! St/*) 3!o#* #># f(om #(#et4
33GC4 3GCi44 3E .7-84
$it% Po)itie Inte(n#! P(e))/(e
one (e))/(e
3.6 )f433-8.4-3.8944 -6.85 )f one (e))/(e
3.6 )f433-8.264-3.8944 -.8 )f
$it% Ne+#tie Inte(n#! P(e))/(e
one (e))/(e
3.6 )f433-8.4-3-.8944 -2.8 )f
one (e))/(e
3.6 )f433-8.264-3-.8944 -.8 )f
E4ample-!arapet 'C & C+
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A! to T(i;/t#( A(e#, not Effectie $in* A(e#
one
-6.85 )f38.@4 -9.88 !f
one
-.8 )f38.@4 -9.58 !f S/mm#(
E"te(io( $#!! St/*) e"ten*e* #)t (oof into #(#et:
one : .82 !f 3to>#(* ;/i!*in+4
one : -9.88 !f 3#># f(om ;/i!*in+4
one i) #nt%in+ >it%in 8ft of t%e co(ne(
one : .82 !f 3to>#(* ;/i!*in+4
one : -9.58 !f 3#># f(om ;/i!*in+4
E4ample-!arapet 'C & C+
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Inte(io( 3(oof )i*e4 P#(#et St/*)
one : .8 !f 3to>#(* #(#et4
one : -9.52 !f 3#># f(om #(#et4
one i) #nt%in+ >it%in 8ft of t%e co(ne(
one : .8 !f 3to>#(* #(#et4 one : -9.72 !f 3#># f(om #(#et4
E4ample-!arapet 'C & C+
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5 Roofto E/iment fo( B/i!*in+) 31$'RS4
3Section 27..84
Office B/i!*in+ )#me #) (eio/)
P!#n Dimen)ion): 8@ >i*e " 2@ !on+
RTU Hei+%t: @ oe( 8@ t#!! c/(;
P(oecte* Hei+%t: @8@@
L#te(#! 'o(ce: '% %3GC(4Af3L;4 3E 27.-24
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Pe(en*ic/!#( to !on+ )i*e
'% 327.7 )f438.743 ft24 29 L;) 3E 27.-24
P#(#!!e! to !on+ )i*e
Ho(i?ont#! >in* fo(ce) #!ie* to +eomet(ic cente( of
e(tic#! (oecte* !#ne of /nit
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5 Roofto E/iment fo( B/i!*in+) 3C0C4
3Section .884 Lo#*) fo( De)i+nin+ t%e E/iment c#;inet enc!o)/(e o( t%e
>#!! comonent) fo( # ent%o/)e
L#te(#! C 0 C (e))/(e)
'% 695 L;) 3f(om (eio/)4
C 0 C L#te(#! Lo#*): '%=Af 695 L;)=8 ft2 6.95 )f
Lo#* i) #!ie* to>#(* o( #># f(om /nit on #!! )i*e)
C 0 C
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Pe()on#! Recommen*#tion 3Not in t%e St#n*#(*4
If t%e /nit i) !#(+e 3oe( 2 ft24, con)i*e( # minim/m
*o>n>#(* >in* !o#*.
C 0 C Lo#*in+ f(om 'i+/(e .-2A
GC .2 3*o>n>#(* comonent4 ' %GC 327.7)f43.24 6 )f
'o( %i+%e( >in* !o#*) #n* !o> )no> !o#*),
#(tic/!#(! !e)) t%#n 8 )f, t%i) m# (o*/ce #
cont(o!!in+ !o#* com;in#tion
E4ample-Rooftop Equip" 'C & C+
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5 Roof Oe(%#n+ 31$'RS4 3Section 27.54
E/iment B/i!*in+ L 6 ft., B ft.
E#e Hei+%t: 8 ft.
Oe(%#n+ $i*t%: ft.
Roof S!oe: .5:82 3 24
Ri*+e #(#!!e! to 6@ )i*e
E"o)/(e C#te+o(: C
Ae(#+e B/i!*in+ Hei+%t: % 8.29@ Q 8@ Section 27.5 (efe(ence) Section 25.. fo(
*i(ection#! (oce*/(e fo( 1$'RS Roof Oe(%#n+
!o#* *ete(min#tion.
E4ample-Roof Oerhang '(W)RS+
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U)e C .9 in E 25.-8 fo( *ete(minin+ (oof #n* >#!!
!o#*) oe( #n* #*#cent to (oof oe(%#n+
GC-i3GCi4 3)f4 3E 25.-84
G .9 3(i+i* )t(/ct/(e4 3Section 26.74
&?t 8. 3fo( com!e"4 &* .9 3B/i!*in+ 1$'RS43T#;!e 26.6-84
< 88 m% 3fo( com!e"4
&? ? 8@ fo( )offit, &? .9 3T#;!e 25.-84
? .26&?&?t&*it% S#me Inte(n#!
P(e))/(e Con*ition)
Note: )i+n) in*ic#te (e))/(e to>#(* o( #>#
f(om )/(f#ce
C%#n+e )i+n) )o 34 i) /, +!o;#!! C%#n+e )i+n) )o 3-4 i) *o>n, +!o;#!!
E4ample-Roof Oerhang '(W)RS+
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Po)itie Inte(n#! P(e))/(e
o% 82.2 )f - .2 )f 88.77 )f
o% 82.2 )f 8.6 )f 22.95 )f
oe(#!! o% i) />#(*
Ne+#tie Inte(n#! P(e))/(e o% 28. )f 9.6 )f 82.9 )f
o% 28. )f 8.9 )f 22.95 )f
oe(#!! o% i) />#(*
Note: Net effect of inte(n#! (e))/(e) i) ?e(o )o
t%#t t%e tot#! /!ift on t%e oe(%#n+ i) t%e )#me.
E4ample-Roof Oerhang '(W)RS+
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Oe(#!! (e))/(e on t%e Lee>#(* Oe(%#n+ i)
c#!c/!#te* t%e )#me >#, ;/t /)e) t%e ne+#tie
(e))/(e on t%e >#!! imme*i#te! #*#cent to
t%e oe(%#n+ fo( *o>n>#(* (e))/(e) on )offit.
B in)ection, tot#! fo(ce on >in*>#(*
oe(%#n+ >i!! cont(o!.
E4ample-Roof Oerhang '(W)RS+
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E4ample-Roof Oerhang
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5 Roof Oe(%#n+ 3C 0 C4 3Section .84
E/iment B/i!*in+
Un!e)) ot%e(>i)e !i)te*, #(#mete() #(e
i*entic#! to t%o)e fo( t%e 1$'RS c#!c/!#tion) Dete(mine C 0 C !o#*) fo( oe(%#n+) of (oof
t(/))e), )#ce* #t 2@-J o.c.
%3GC4 3GCi4 )f 3E .8-84
&*
.9 3B/i!*in+ C0C4 3T#;!e 26.6-84
A!! ot%e( #(#mete() fo( % #(e )#me #) fo(
1'$RS
E4ample-Roof Oerhang 'C & C+
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% .263.9438.43.9438842 2.6 )f
Ente( 'i+/(e .-2B fo( Roof Oe(%#n+ C 0 C coefficient)
Dete(mine Effectie $in* A(e# of St/*)
G(e#te( of T(i;/t#( A(e# o( Effectie $i*t%
Effectie $in* A(e# Definition 3Section 26.24 G(e#te( of 2.@ o( 3+oe(n)4
Len+t%= @= 8.@
Effectie $in* A(e#: @"2@ 6. ft2
If Effectie $in* A(e# F 5 ft2, /)e 1'$RS !o#*)
Dete(mine M#J *i)t#nce 3'i+/(e .-8 #n* .-2A4
Le))e( of 8 of B .83@4 @ #n* .%
.38.29@4 .8@
@ +oe(n)
E4ample-Roof Oerhang 'C & C+
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Not !e)) t%#n t%e +(e#te( of of B .3@4 8.2@
o( @ 3@ cont(o!)4
# @ 3e/#! to >i*t% of oe(%#n+ t%e(efo(e, one 8
(e))/(e) #(e not #!ic#;!e to #n #(t of t%e
oe(%#n+4
one 2: GC -2.2
32.6 )f43-2.24 3.894 -9.28 )f
>it% o)itie inte(n#! ;/i!*in+ (e))/(e
32.6 )f43-2.24 3-.894 -7.8 )f
>it% ne+#tie inte(n#! ;/i!*in+ (e))/(e
one : GC -.5
32.6 )f43-.54 3.894 -7.7 )f
>it% o)itie inte(n#! ;/i!*in+ (e))/(e
E4ample-Roof Oerhang 'C & C+
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32.6 )f43-.54 3-.894 -96.8 )f
>it% ne+#tie inte(n#! ;/i!*in+ (e))/(e
'o( t%e oe(%#n+ o(tion of t%e t(/)):
T(i;/t#( $i*t% 2@
U>#(* fo(ce on t%e enti(e t(/)) en* i): one 2: 3-9.28 )f432@4 -886.2 !f
3/>#(*4
one : 3-7.7 )f432@4 -897.7 !f
3/>#(*4
T%e)e #(e NOT t%e !o#*) on t%e )offit m#te(i#! .
E4ample-Roof Oerhang 'C & C+
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Section .8 )t#te) t%#t t%e e"te(n#! coefficient fo( t%e
coe(in+ on t%e /n*e()i*e of t%e (oof oe(%#n+ 3)offit4 i) t%e
)#me #) t%e e"te(n#! (e))/(e coefficient on t%e #*#cent
>#!! )/(f#ce, *ete(mine* f(om 'i+/(e .-8 o( 'i+/(e .6-
8, #) #!ic#;!e.
U)e of t%e GC >it% ne+#tie inte(n#! (e))/(e ie!*) t%e
+(e#te)t />#(* !o#* on t%e m#te(i#! on t%e /n*e()i*e of
t%e oe(%#n+ on t%e >in*>#(* >#!!.
U)e of t%e GC >it% o)itie inte(n#! (e))/(e ie!*) t%e
+(e#te)t *o>n>#(* !o#* on t%e m#te(i#! on t%e
/n*e()i*e of t%e oe(%#n+ on t%e !ee>#(* >#!!. 'o( t%i) ;/i!*in+, #))/min+ effectie >in* #(e# i) t%e
)#me #) fo( t%e t(/)) oe(%#n+:
E4ample-Roof Oerhang 'C & C+
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$in*>#(* $#!! Soffit 1#te(i#! 3'i+/(e .-84
one #n* one : GC 8.
32.6 )f438.4 3-.894 29.96 )f
#ctin+ />#(*
Lee>#(* $#!! Soffit 1#te(i#! 3'i+/(e .-84 one : GC -8.8
32.6 )f43-8.84 3.894 -8.8 )f
3#ctin+ *o>n>#(*4
one : GC -8.
32.6 )f43-8.4 3.894 -9.6 )f3#ctin+ *o>n>#(*4
E4ample-Roof Oerhang 'C & C+
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5 C%emic#! Si!o 3Ot%e( St(/ct/(e 1$'RS4
3Section 27.4
Si!o Dimen)ion): % 2@, D .@
$e!*e* Stee! T#n: )moot% )i*e), no !#**e( Roof S!oe: 8:82 3conic#!4
1#"im/m (i)e: 2. inc%e) 3con)i*e(
cont(i;/tion to >in* !o#*, ne+!i+i;!e4
Un!e)) ot%e(>i)e !i)te*, #(#mete() fo(
c#!c/!#tion of ? #(e i*entic#! to t%o)e fo( t%e1$'RS c#!c/!#tion) fo( e/iment ;/i!*in+.
' ?GCfAfL;) 3E 27.-84
E4ample- Chemical S=LO '(W)RS+
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? .26&?&?t&*
%=D 2@=@ .
1/)t inte(o!#te ;et>een %=D8. #n* %=D 5.
Cf .5
' 329.7 )f43.943.54 Af 389. )f4Af ' 389. )f4AfQ 386)f4Af
E4ample- Chemical S=LO '(W)RS+
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Af @"2@ 8 ft2
' 389. )f438 ft24 89 L;)
T%i) i) con)e(#tie, OR c#!c/!#te ' fo( inc(e#)e in
(e))/(e #) %ei+%t inc(e#)e)
8
.263.9438.43.74882 25. )f
38-24 .23.7438.43.74 38842 29.7 )f
'o( -8@: D=V ? @=S(t325.)f4 .76 Q 2.
Cf .5
'-8 325. )f43.943.54Af 85. )f AfF 86 )f Af '-8 385. )f43@438@4 85 L;).
'8-2 389. )f43@43@4 68 L;).
Tot#! ' on Si!o: 85 L;) 68 L;) 8569 L;)
E4ample- Chemical S=LO '(W)RS+
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Con)e(#tie OT1: 389 L;)438@4 89, ft-!;)
1o(e Det#i!e* OT1: 385 L;)438@=24368
L;)438@@=24 85,95 ft-!;)
T%e t#!!e( t%e )t(/ct/(e i), t%e mo(e imo(t#nt it i) to
/)e t%e )tee* >in* fo(ce #(o#c%.
E4ample- Chemical S=LO '(W)RS+
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uestions