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©L.
Prie
to-P
orta
r -20
08
EGN
EGN
-- 543
9 Th
e D
esig
n of
Tal
l Bui
ldin
gs54
39 T
he D
esig
n of
Tal
l Bui
ldin
gs
Lect
ure
08Le
ctur
e 08
ASCE
7AS
CE 7
-- 02
Solv
ed P
robl
em #
1:02
Sol
ved
Prob
lem
#1:
Anal
ytic
al M
etho
d 2
(for b
uild
ings
< 6
0 fe
et h
igh)
.An
alyt
ical
Met
hod
2 (fo
r bui
ldin
gs <
60
feet
hig
h).
This
lect
ure
appl
ies t
he A
SCE
7-02
cod
e re
quir
emen
ts fo
r w
ind
(Sec
tion
6.0)
to a
sim
ple
stru
ctur
e an
d an
alyz
es it
with
,
The
ASCE
7-0
2 M
etho
d 2,
the
Anal
ytic
al M
etho
dfo
r bu
ildin
gs sm
alle
r th
an 6
0 fe
et in
he
ight
.
The
stru
ctur
e ch
osen
is a
war
ehou
se-o
ffice
bui
ldin
g in
dow
ntow
n Ta
mpa
. Its
di
men
sions
are
100
feet
long
by
50 fe
et w
ide
by 2
0 fe
et ta
ll.
A d
raw
ing
is sh
own
on sl
ide
#3 d
epic
ting
the
loca
tion
of a
ll th
ew
indo
ws a
nd d
oors
. Th
e lo
catio
n of
thes
e w
indo
ws a
nd d
oors
are
eith
er in
the
field
(or
inte
rnal
) zon
es o
r in
the
end
(or
exte
rnal
) zon
es.
The
anal
ysis
cons
ists o
f fin
ding
all
pres
sure
s affe
ctin
g ev
ery
part
of t
his s
truc
ture
that
co
me
from
all
four
dir
ectio
ns.
Fina
lly, w
hen
all t
he p
ress
ures
hav
e be
en c
alcu
late
d, th
e en
gine
er w
ill c
hoos
e th
e la
rges
t pos
itive
pre
ssur
ean
d th
e la
rges
t neg
ativ
e pr
essu
refo
r th
e de
sign
of th
e bu
ildin
g.
The
exam
ple:
a si
ngle
-sto
ry w
areh
ouse
bui
ldin
g, 1
00 fe
et lo
ng, 5
0 fe
et a
nd 2
0 fe
et ta
ll.
The
loca
tion
of th
e w
indo
ws a
nd d
oors
are
cri
tical
: are
they
in th
e “f
ield
”or
in th
e “e
nd”
zone
s; a
re th
ey “
debr
is re
sista
nt”
or n
ot, i
n w
hich
cas
e, th
is fa
ce o
f the
bu
ildin
g is
brea
ched
dur
ing
a hu
rric
ane.
The
basic
form
ula
used
to c
ompu
te th
e w
ind
desig
n pr
essu
re p
that
is a
pplie
d to
a
stru
ctur
e or
a p
ortio
n of
a st
ruct
ure
is,
The
win
d ve
loci
ty c
omes
from
Cou
nty
map
s in
lieu
of F
ig 6
-1b
pg 7
3
This
form
ula
is pe
rfor
med
upo
n 10
diff
eren
t zon
es o
f the
stru
ctur
e in
4 d
iffer
ent w
ind
dire
ctio
ns fo
r bo
th th
e tr
ansv
erse
and
the
build
ing’
s lon
gitu
dina
l dir
ectio
ns. T
he
anal
ysis
is al
so p
erfo
rmed
for
both
the
MW
FRS
and
C&
C. T
here
fore
, the
re a
re a
tota
l of
160
cal
cula
ted
pres
sure
s. Fr
om th
ese,
the
engi
neer
will
cho
ose
the
larg
est p
ositi
ve a
nd
nega
tive
pres
sure
s for
the
final
des
ign.
() (
)(
)2
000
256
zzt
dp
pip
.K
KK
VI
GC
GC
=!
A c
onst
ant /
Tab
le 6
-3 p
g 75
/ Fi
gure
6-4
pg
47+4
8 / T
able
6-4
pg
76 /
Tabl
e 6-
1 pg
73
A c
onst
ant =
0.8
5 or
Equ
atio
n 6-
4 pg
30
/ Fig
6-6
to 6
-8 p
g 50
-53
/ Fig
6-5
pg
49
()
()
=!
zp
piwh
ere
pq
GC
GC
()(
)2
000
256
=zt
zd
p.
KK
VI
fK
acto
r
The
wind
exp
osur
e ca
tego
ry c
oeffi
cien
t Kz
shal
l be
take
n fr
om A
SCE
7-02
, Sec
tion
6,
page
75,
Tab
le 6
-3. T
he E
xpos
ure
Cat
egor
y is
disc
usse
d in
ASC
E 6.
5.6,
pag
es 2
8 an
d 29
. 6.5.
6 Ex
posu
re. F
or e
ach
win
d di
rect
ion
cons
ider
ed, a
n ex
posu
re c
ateg
ory
that
ade
quat
ely
refle
cts
the
char
acte
ristic
s of g
roun
d ro
ughn
ess
and
surf
ace
irreg
ular
ities
sha
ll be
dete
rmin
ed fo
r the
site
at w
hich
the
build
ing
or s
truct
ure
is to
be c
onst
ruct
ed. A
ccou
nt s
hall
be ta
ken
of v
aria
tions
in g
roun
d su
rfac
e ro
ughn
ess
that
aris
es fr
om n
atur
al to
pogr
aphy
and
ve
geta
tion
as w
ell a
s co
nstru
cted
feat
ures
.
6.5.
6.1
Win
d D
irec
tions
and
Sec
tors
. For
eac
h se
lect
ed w
ind
dire
ctio
n at
whi
ch th
e w
ind
load
s ar
e to
be
eval
uate
d, th
e ex
posu
re o
f the
bui
ldin
g or
stru
ctur
e sh
all b
e de
term
ined
for t
he tw
o up
win
d se
ctor
s ext
endi
ng 4
5 de
gree
s eith
er s
ide
of th
e se
lect
ed w
ind
dire
ctio
n.
The
expo
sure
s in
thes
e tw
o se
ctor
s sh
all b
e de
term
ined
in a
ccor
danc
e w
ith S
ectio
ns 6
.5.6
.2
and
6.5.
6.3
and
the
expo
sure
resu
lting
in th
e hi
ghes
t win
d lo
ads
shal
l be
used
to re
pres
ent
the
win
ds fr
om th
at d
irect
ion.
6.5.
6.2
Surf
ace
Rou
ghne
ss C
ateg
orie
s. A
gro
und
surf
ace
roug
hnes
s w
ithin
eac
h 45
-deg
ree
sect
or s
hall
be d
eter
min
ed fo
r a d
ista
nce
upw
ind
of th
e si
te a
s de
fined
in S
ectio
n 6.
5.6.
3 fr
om th
e ca
tego
ries
defin
ed b
elow
, for
the
purp
ose
of a
ssig
ning
an
expo
sure
cat
egor
y as
de
fined
in S
ectio
n 6.
5.6.
3.
Surf
ace
Roug
hnes
s B:U
rban
and
sub
urba
n ar
eas,
woo
ded
area
s or
oth
er te
rrai
n w
ith
num
erou
s cl
osel
y sp
aced
obs
truct
ions
hav
ing
the
size
of s
ingl
e-fa
mily
dw
ellin
gs o
r lar
ger.
Surf
ace
Roug
hnes
s C:O
pen
terr
ain
with
sca
ttere
d ob
stru
ctio
ns h
avin
g he
ight
s ge
nera
lly
less
than
30
ft (9
.1 m
). Th
is c
ateg
ory
incl
udes
flat
ope
n co
untry
, gra
ssla
nds,
and
all
wat
er
surf
aces
in h
urric
ane-
pron
e re
gion
s.
Surf
ace
Roug
hnes
s D:F
lat,
unob
stru
cted
are
as a
nd w
ater
sur
face
s ou
tsid
e hu
rric
ane-
pron
e re
gion
s. T
his c
ateg
ory
incl
udes
smoo
th m
ud fl
ats,
salt
flats
, and
unb
roke
n ic
e.
This
Exam
ple
ASCE
7AS
CE 7
-- 02
Tabl
e 6
02 T
able
6-- 3
, pag
e 75
3, p
age
75Th
is Ex
ampl
e
K h=
K z=
0.70
Cas
e 1
(C&
C) a
nd C
ase
2 (M
WFR
S)
()(
)(
)2
000
256
070
=z
dt
Kp
..
KV
Ifa
ctor
whe
re K
ztis
the
Topo
grap
hic
Fact
or, a
nd is
app
lied
to st
ruct
ures
sitti
ng o
n hi
lls, r
idge
s an
d es
carp
men
ts (A
SCE
7-02
, Sec
tion
6.5.
7, p
ages
29
and
30).
Thi
s top
ogra
phic
fact
or
is re
quir
ed w
hen,
1. T
he h
ill, r
idge
, or e
scar
pmen
t is
isol
ated
and
uno
bstru
cted
upw
ind
by o
ther
sim
ilar
topo
grap
hic
feat
ures
of c
ompa
rabl
e he
ight
for 1
00 ti
mes
the
heig
ht o
f the
topo
grap
hic
feat
ure
(100
H) o
r 2 m
iles (
3.22
km
), w
hich
ever
is le
ss. T
his
dist
ance
sha
ll be
mea
sure
d ho
rizon
tally
from
the
poin
t at w
hich
the
heig
ht H
of th
e hi
ll, ri
dge,
or e
scar
pmen
tis
det
erm
ined
;2.
The
hill
, rid
ge, o
r esc
arpm
ent p
rotru
des
abov
e th
e he
ight
of u
pwin
d te
rrai
n fe
atur
es
with
in a
2-m
ile (3
.22-
km) r
adiu
s in
any
quad
rant
by
a fa
ctor
of t
wo
or m
ore;
3. T
he s
truct
ure
is lo
cate
d as
sho
wn
in F
igur
e 6-
4 in
the
uppe
r hal
f of a
hill
or r
idge
or n
ear
the
cres
t of a
n es
carp
men
t;4.
H /
L h
0.2;
and
5. H
is g
reat
er th
an o
r equ
al to
15
feet
(4.5
m) f
or E
xpos
ures
C a
nd D
and
60
feet
(18
m)
for E
xpos
ure
B.
Whe
n no
t req
uire
d, u
se K
zt=
1.0.
This
Exam
ple
#1.
Figu
re 6
-4 d
escr
ibes
the
para
met
ers o
f the
Top
ogra
phic
Fac
tor,
()(
)()
()
20
0025
60
701
0=
dp
..
.V
IK
fact
or
whe
re K
dis
the
Win
d D
irec
tiona
lity
Fact
or, a
nd is
onl
y ap
plie
d w
hen
used
in
conj
unct
ion
with
load
com
bina
tions
spec
ified
in S
ectio
ns 2
.3 a
nd2.
4 (p
ages
5 a
nd 6
of
ASC
E 7-
02, S
ectio
n 6.
5.4.
4, p
age
28).
The
load
com
bina
tions
can
be,
for
exam
ple,
-Liv
e lo
ad +
win
d, o
r-D
ead
load
+ w
ind,
or
-Sno
w +
win
d, e
tc, e
tc.
The
Win
d D
irec
tiona
lity
Fact
or is
obt
aine
d fr
om A
SCE
Tabl
e 6-
4, p
age
76:
This
Exam
ple
#1:
K d=
0.85
for
both
MW
FRS
and
C&
C.
()(
)()(
)()
()
20
0025
60
701
00
85=
p.
..
.I
faV
ctor
whe
re V
is th
e Ba
sic W
ind
Spee
d, a
nd is
ass
umed
to c
ome
from
any
dir
ectio
n an
d ca
n be
obt
aine
d fr
om lo
cal d
ata
(ASC
E 7-
02, S
ectio
n 6.
5.4,
pag
e 28
).
Basic
Win
d Sp
eed
ASC
E-7-
02, F
igur
e 6-
1b.
With
in th
e St
ate
of F
lori
da th
e w
ind
spee
ds a
re o
btai
ned
from
the
loca
l cou
nty
whe
re th
e pr
ojec
t is l
ocat
ed th
roug
h th
e co
unty
’s w
ind
map
s, th
roug
h,
ww
w.d
ca.st
ate.
fl.us
/fbc/
map
s/2_m
aps.h
tm
Som
e co
untie
s allo
w in
terp
olat
ion
betw
een
win
d sp
eed
lines
, whi
lst o
ther
s do
not.
To o
btai
n a
win
d m
ap o
f thi
s spe
cific
exa
mpl
e in
dow
ntow
n Ta
mpa
(Hill
sbor
ough
C
ount
y), u
se th
is ad
dres
s,
ww
w.d
ca.st
ate.
fl.us
/fbc/
inde
x_pa
ge/m
aps/c
ount
y_m
aps/h
illsb
orou
gh2.
Hill
sbor
ough
Cou
nty
does
allo
w in
terp
olat
ion,
alth
ough
it is
not
pra
ctic
al.
This
Exam
ple
#1’s
site
.U
se V
= 12
0 m
ph.
()(
)()(
)()
()
20
0025
60
701
00
8512
0=
Ip
..
..
fact
or
whe
re I
is th
e Im
port
ance
Fac
tor,
and
is b
ased
on
the
use
of th
e st
ruct
ure
as w
ell
as th
e N
atur
e of
Occ
upan
cy (A
SCE
7-02
, Sec
tion
6.5.
5, p
age
28).
The
Impo
rtan
ce F
acto
r (fr
om A
SCE
Tabl
e 6-
1, p
age
73),
Cat
egor
y II
V=
120
mph
This
Exam
ple:
I = 1
.0
()(
)()(
)()(
)()
()(
)
20
0025
60
701
00
8512
01
0
219
= =
p.
..
..
facto
r
p.
psf
facto
r
Thus
, the
“ra
w”
win
d pr
essu
re (a
lso k
now
n as
qz,
the
velo
city
pre
ssur
e) is
,
This
“raw
”w
ind
pres
sure
now
nee
ds to
be
mod
ified
by
the
inte
rnal
and
ext
erna
l pr
essu
re c
oeffi
cien
ts (t
he “
fact
or”)
in o
rder
to d
eter
min
e w
hat i
s the
act
ual
pres
sure
that
is g
oing
to b
e ap
plie
d at
diff
eren
t poi
nts o
f the
stru
ctur
e.
WIN
D
An
unbr
each
ed h
ouse
is su
bjec
ted
to p
ositi
ve a
nd n
egat
ive
pres
sure
s fro
m th
e ex
tern
al
win
d.
WIN
D
Whe
n th
e ho
use
is br
each
ed (a
bro
ken
win
dow
, or
a do
or th
at lo
ses i
ts la
tch,
etc
) the
w
ind
ente
ring
the
hous
e w
ill q
uick
ly in
crea
se th
e lo
ads o
n th
e re
mai
ning
win
dow
s, do
ors a
nd r
oof u
ntil
they
too,
fail.
WIN
D
The
pres
sure
coe
ffici
ents
will
add
pre
ssur
e on
som
e w
alls
and
roof
(see
the
win
d ef
fect
upo
n th
e ri
ght s
ide
wal
l and
roo
f) an
d su
btra
ct o
n ot
hers
. The
ana
lysis
sear
ches
fo
r th
e la
rges
t pos
itive
and
neg
ativ
e pr
essu
res o
n th
e st
ruct
ure.
()
()
() (
)(
)21
9
=!
=!
Zpi
pi
p
p
pq
GC
p.
psf
GCGC
GC
Now
the
“raw
”pr
essu
re (a
lso k
now
n as
qz,
the
velo
city
pre
ssur
e) m
ust b
e m
odifi
ed
by th
e pr
essu
re c
oeffi
cien
ts,
whe
re G
C pii
s the
Inte
rnal
Pre
ssur
e Co
effic
ient
and
is ba
sed
on th
e Bu
ildin
g En
clos
ure
Cla
ssifi
catio
n (A
SCE
07-2
, Sec
tion
6.5.
11.1
, pag
e 31
).
Wha
t is t
he w
ind
pres
sure
doi
ng in
tern
ally
? H
ow d
oes t
he w
ind
affe
ct a
n En
clos
ed
Build
ing,
whi
ch is
the
case
for
this
exam
ple?
Even
enc
lose
d bu
ildin
gs h
ave
crac
ks a
roun
d th
e do
ors a
nd th
e w
indo
ws,
so th
at th
e bu
ildin
g “b
reat
hs”
and
feel
s a p
ortio
n of
the
raw
pre
ssur
e.
A B
uild
ing
Encl
osur
e is
defin
ed in
ASC
E 7-
02, S
ectio
n 6.
2, p
age
23,
Build
ing,
ope
n:A
bui
ldin
g ha
ving
eac
h w
all a
t lea
st 8
0% o
pen.
Thi
s co
nditi
on is
expr
esse
d fo
r eac
h w
all b
y th
e eq
uatio
n Ao
0.
8 Ag
whe
re: A
o =
tota
l are
a of
ope
ning
s in
a w
all t
hat r
ecei
ves
posi
tive
exte
rnal
pre
ssur
e, in
ft2
(m2 )
Ag
= th
e gr
oss
area
of t
hat
wal
l in
whi
ch A
o is
iden
tifie
d in
ft2
(m2 )
.
Build
ing,
par
tially
enc
lose
d:A
bui
ldin
g w
hich
com
plie
s w
ith b
oth
of th
e fo
llow
ing
cond
ition
s:1.
The
tota
l are
a of
ope
ning
s in
a w
all t
hat r
ecei
ves
posi
tive
exte
rnal
pre
ssur
e ex
ceed
s th
e su
m o
f the
are
as o
f ope
ning
s in
the
bala
nce
of th
e bu
ildin
g en
velo
pe (w
alls
and
roof
) by
mor
e th
an 1
0%, a
nd2.
The
tota
l are
a of
ope
ning
s in
a w
all t
hat r
ecei
ves
posi
tive
exte
rnal
pre
ssur
e ex
ceed
s 4
ft2(0
.37
m2 )
, or 1
% o
f the
are
a of
that
wal
l, w
hich
ever
is s
mal
ler,
and
the
perc
enta
ge o
f op
enin
gs in
the
bala
nce
of th
e bu
ildin
g en
velo
pe d
oes
not e
xcee
d20
%.
Thes
e co
nditi
ons a
re e
xpre
ssed
by
the
follo
win
g eq
uatio
ns:
1. A
o >
1.10
Aoi
2. A
o >
4 ft2
(0.3
7 m
2 ) or
> 0
.01A
g, w
hich
ever
is sm
alle
r, a
nd A
oi /A
gi
0.20
whe
re: A
o, A
g ar
e as
def
ined
fo
r O
pen
Build
ing
Aoi =
the
sum
of t
he a
reas
of o
peni
ngs i
n th
e bu
ildin
g en
velo
pe (w
alls
and
roof
) not
in
clud
ing
Ao, i
n ft2
(m2 )
Agi =
the
sum
of t
he g
ross
surf
ace
area
s of t
he b
uild
ing
enve
lope
(wal
ls an
d ro
of)
not i
nclu
ding
Ag,
in ft
2(m
2 ).
Build
ing,
enc
lose
d:A
bui
ldin
g th
at d
oes
not c
ompl
y w
ith th
e re
quire
men
ts fo
r ope
n or
pa
rtial
ly e
nclo
sed
build
ings
.
This
Exa
mpl
e.
This
Exam
ple
#1:
() (
)(
)21
90
18
=
!±
pp
.G
C.
psf
whe
re G
C pis
the
Exte
rnal
Pre
ssur
e Co
effic
ient
and
is co
mpu
ted
sepa
rate
ly fo
r th
e M
WFR
S ca
ses a
nd th
e C
&C
cas
es (A
SCE
7-02
, Sec
tion
6.5.
11.2
, pag
e 31
).
Thes
e ex
tern
al p
ress
ures
are
also
det
erm
ined
and
app
lied
base
d on
whi
ch z
one
of
the
build
ing
is be
ing
eval
uate
d (th
at is
, in
the
field
or in
the
end
zone
s).
Up
to th
is po
int,
ASC
E 7-
02’s
pro
cedu
re is
iden
tical
for
both
the,
-Met
hod
2, A
naly
tical
Pro
cedu
re fo
r an
y he
ight
, and
-Met
hod
2, A
naly
tical
Pro
cedu
re fo
r th
e ro
of a
t <
60 fe
et in
hei
ght.
From
now
on,
the
met
hod
of fi
ndin
g G
C pis
diffe
rent
for
thes
e tw
o.
The
dist
ance
aof
the
end
zone
scor
resp
onds
to th
e C
ompo
nent
s and
Cla
ddin
g ca
se:
In su
mm
ary,
a =
0.10
L=
0.10
B
th
e le
ast o
f the
se=
0.40
h
a =
0.04
L=
0.04
B
bu
t not
less
than
thes
e=
3 fe
et
This
Exam
ple:
a =
(0.1
0)(5
0 ft)
= 5
feet
= (0
.40)
(20
ft) =
8 fe
et
= (0
.04)
(50
ft) =
2 fe
et=
3 fe
etth
eref
ore
a =
5 fe
et
() (
)(
)21
90
18
=
!±
pp
.G
C.
psf
Cal
cula
ting
GC p
for
the
MW
FRS
case
is re
pres
ente
d by
GC p
f,
The
valu
es o
f GC p
far
e fo
und
in A
SCE
7-02
, Sec
tion
6.5.
11.2
, pag
e 31
, Fig
ure
6-10
, pa
ges 5
5 an
d 56
.
Figu
re 6
-10,
pag
es 5
5 an
d 56
.
An
expa
nded
vie
w o
f the
ten
(10)
zon
es o
f a b
uild
ing
unde
r a
Tran
sver
se A
load
ing:
The
calc
ulat
ions
of G
C pf
for
the
MW
FRS
case
invo
lve
thes
e te
n (1
0) z
ones
; not
ice
the
valu
es g
iven
in th
e Ta
ble
for
our
Exam
ple
#1’s
flat
roo
f (
= 0°
):
This
Exam
ple:
a fl
at r
oof.
This
line
of c
oeffi
cien
ts a
re n
ow u
sed
to c
alcu
late
the
pres
sure
s sho
wn
on th
e sp
read
-sh
eet s
how
n on
the
next
slid
e.
-5.5
0-1
3.40
-0.4
321
.9 p
sf4E
-7.7
0-1
5.50
-0.5
321
.9 p
sf3E
-19.
50-2
7.40
-1.0
721
.9 p
sf2E
17.3
09.
400.
6121
.9 p
sf1E
-5.9
0-1
3.80
-0.4
521
.9 p
sf6
-5.9
0-1
3.80
-0.4
521
.9 p
sf5
-2.4
0-1
0.30
-0.2
921
.9 p
sf4
-4.2
0-1
2.00
-0.3
721
.9 p
sf3
-11.
20-1
9.10
-0.6
921
.9 p
sf2
12.7
04.
820.
4021
.9 p
sf1
Usi
ng -G
Cpi
Usi
ng +
GC
piq z
zone
Des
ign
pres
sure
sG
Cpf
Vel
ocity
pre
ssur
eB
uild
ing
The
desig
n pr
essu
res f
or th
e M
WFR
S at
all
ten
zone
s for
a T
rans
vers
e A
are
:
Con
sider
the
first
line
of c
alcu
latio
ns fo
r th
e bu
ildin
g’s z
one
#1,
Thus
, for
zon
e #1
, the
pre
ssur
es r
ange
from
+4.
82 p
sf to
+12
.70
psf;
ther
efor
e, w
e w
ould
cho
ose
+12.
70 p
sf fo
r ou
r de
sign
pres
sure
.
This
proc
edur
e no
w c
ontin
ues f
or a
ll te
n zo
nes i
n fo
ur (4
) dir
ectio
ns fo
r th
e tr
ansv
erse
w
ind
load
ing
and
the
four
(4) d
irec
tions
for
the
long
itudi
nal w
ind
load
ing,
or
a to
tal
80 c
alcu
late
d pr
essu
res f
or th
e M
WFR
S ca
se.
Cho
ose
the
larg
est p
ositi
ve a
nd th
e la
rges
t neg
ativ
e pr
essu
res.
()
()
()
()
()
()
()
()
(21.
9)
0.18
(21.
9)
0.18
Usi
ng th
e po
sitiv
e va
lue
of
yie
lds,
(21.
9)
0.40
0.18
Usi
ng th
e ne
gativ
e va
lue
of
yie
lds,
(2
0.40
4.82 12
.70
1.9
)0.
400.
18
pf
pi pi
pps
fps
f
GC
pps
GC
f
GC
p
psf p
pssf
f
=!
±=
!±
=!
=
=!
!=
+12.
70 p
sf
-19.
10 p
sf
-12.
00 p
sf-1
0.30
psf
-13.
80 p
sf
-13.
80 p
sf
+17.
30 p
sf
-27.
40 p
sf
-15.
50 p
sf
-13.
40 p
sf
The
ten
zone
s for
the
Tran
sver
se A
can
now
be
show
n w
ith th
eir
calc
ulat
ed d
esig
n pr
essu
res:
Win
d di
rect
ion
Con
sider
now
, wha
t wou
ld h
appe
n to
the
desig
n pr
essu
res i
f the
roo
f had
a sm
all
pitc
h of
=
20°(
whi
ch c
orre
spon
ds r
ough
ly to
a p
itch
of 5
:12)
,
This
new
var
iant
of E
xam
ple
#1 w
ith
= 20
°,
-10.
10-1
8.00
-0.6
421
.9 p
sf4E
-11.
20-1
9.10
-0.6
921
.9 p
sf3E
-19.
50-2
7.40
-1.0
721
.9 p
sf2E
21.5
013
.60
0.80
21.9
psf
1E
-5.9
0-1
3.80
-0.4
521
.9 p
sf6
-5.9
0-1
3.80
-0.4
521
.9 p
sf5
-5.5
0-1
3.40
-0.4
321
.9 p
sf4
-6.6
0-1
4.50
-0.4
821
.9 p
sf3
-11.
20-1
9.10
-0.6
921
.9 p
sf2
15.5
07.
700.
5321
.9 p
sf1
nega
tive
posi
tive
q zzo
ne
Des
ign
pres
sure
sG
Cpf
Vel
ocity
Pre
ssur
eB
uild
ing
Not
ice
the
sligh
t inc
reas
e in
pre
ssur
e du
e to
the
incr
ease
in th
e ro
of’s
pitc
h, a
lthou
gh
zone
#2E
has
not
cha
nged
,
The
mai
n w
ind
forc
e re
sistin
g sy
stem
(MW
FRS)
des
ign
pres
sure
s jus
t fou
nd a
re u
sed
as th
e la
tera
l for
ces u
pon
the
stru
ctur
al sk
elet
on fr
ame
of th
e bu
ildin
g, su
ch a
s the
st
eel f
ram
e, th
e re
info
rced
con
cret
e co
lum
ns, b
eam
s and
slab
s, sh
ear
wal
ls, e
tc.
The
desig
n pr
essu
res f
rom
the
MW
FRS
port
ion
are
appl
ied
to th
e co
lum
ns a
nd b
eam
s th
roug
h th
e us
e of
the
trib
utar
y ar
eas.
For
exam
ple,
if th
e co
lum
ns a
re sp
aced
at 3
0-fo
ot in
terv
als,
and
the
floor
-to-fl
oor
heig
ht is
10-
feet
, the
trib
utar
y ar
ea is
10’
x 30
’=
300
SF m
ultip
lied
by th
e la
rges
t pos
itive
or
nega
tive
desig
n pr
essu
res f
ound
in th
e tw
o pr
evio
us ta
bles
.
Now
we
will
cal
cula
te th
e de
sign
pres
sure
s for
the
Com
pone
nts a
nd C
ladd
ings
(C&
C).
The
com
pone
nts a
nd c
ladd
ing
are,
for
exam
ple,
the
roof
cov
erin
gs, w
all c
over
ings
, aw
ning
s, ca
nopi
es, e
tc, a
nyth
ing
that
is n
ot a
ffect
ed b
y th
e in
tern
al p
ress
ure
GC p
i = 0
. Th
ese
C&
C e
xter
nal p
ress
ures
are
app
lied
to si
ngle
com
pone
nts,
a“s
tand
-alo
ne”
(one
ca
nopy
, one
doo
r, e
tc) a
nd a
re a
func
tion
of th
e su
rfac
e “e
ffect
ive
area
”of
that
co
mpo
nent
. The
smal
ler
the
effe
ctiv
e ar
ea, t
he m
ore
inte
nse
the
pres
sure
, ver
sus,
the
larg
er th
e ef
fect
ive
area
, the
pre
ssur
e be
com
es sm
alle
r, e
tc.
In th
e A
SCE
Met
hod
1: T
he S
impl
ified
Met
hod
thes
e tw
o se
para
te p
roce
dure
s (M
WFR
S an
d C
&C
) are
uni
ted
into
a si
ngle
pro
cedu
re.
Con
sider
now
the
Exte
rnal
Pre
ssur
e C
oeffi
cien
ts fo
r th
e w
alls
inth
e C
&C
cas
e (A
SCE
7-02
, Fig
ures
6-1
a an
d 6-
1b, p
ages
57
and
58):
Wal
l coe
ffici
ents
Thes
e ar
e th
e C
&C
roo
f coe
ffici
ents
,
Con
sider
the
Exte
rnal
Pre
ssur
e C
oeffi
cien
ts fo
r a
wal
l com
pone
ntth
at h
as a
n ar
ea o
f on
ly 1
0 sq
uare
feet
:
The
desig
n pr
essu
res f
or a
C&
C o
f onl
y 10
SF
of w
all e
ffect
ive
area
are
,
23.3
016
.20
1.00
21.9
psf
5(-)
-24.
00-3
1.10
-1.4
021
.9 p
sf5(
+)
23.2
016
.20
1.00
21.9
psf
4(-)
-18.
10-2
5.20
-1.1
021
.9 p
sf4(
+)
Usi
ng -G
Cpi
Usi
ng +
GC
piq z
zone
Des
ign
pres
sure
sG
Cpf
Vel
ocity
Pre
ssur
eB
uild
ing
Now
wha
t hap
pens
whe
n th
e co
mpo
nent
Now
wha
t hap
pens
whe
n th
e co
mpo
nent
’’ s a
rea
is in
crea
sed
to 1
00 sq
uare
feet
?s a
rea
is in
crea
sed
to 1
00 sq
uare
feet
?
The
desig
n pr
essu
res f
or th
e 10
0 SF
wal
l are
smal
ler,
19.3
012
.20
-0.8
021
.9 p
sf5(
-)
-17.
10-2
4.20
-1.0
521
.9 p
sf5(
+)
19.3
012
.20
0.80
21.9
psf
4(-)
-15.
20-2
2.30
-0.9
521
.9 p
sf4(
+)
Usi
ng -G
Cpi
Usi
ng +
GC
piq z
zone
Des
ign
pres
sure
sG
Cpf
Vel
ocity
Pre
ssur
eB
uild
ing
Sim
ilarl
y, fo
r a
roof
effe
ctiv
e ar
ea o
f onl
y 10
squa
re fe
et, t
heco
effic
ient
s are
,
Ther
efor
e, th
e de
sign
pres
sure
s for
a r
oof c
ompo
nent
10
SF is
,Th
eref
ore,
the
desig
n pr
essu
res f
or a
roo
f com
pone
nt 1
0 SF
is,
-57.
40-6
5.30
-2.8
021
.9 p
sf3(
-)
10.5
02.
600.
3021
.9 p
sf3(
+)
-35.
50-4
3.40
-1.8
021
.9 p
sf2(
-)
10.5
02.
600.
3021
.9 p
sf2(
+)
-18.
00-2
5.80
-1.0
021
.9 p
sf1(
-)
10.5
02.
600.
3021
.9 p
sf1(
+)
Usi
ng -G
Cpi
Usi
ng +
GC
piq z
zone
Des
ign
pres
sure
sG
Cpf
Vel
ocity
Pre
ssur
eB
uild
ing
Con
tras
t the
hig
h pr
essu
res o
n a
roof
com
pone
nt 1
0 SF
with
the
sam
e co
mpo
nent
th
at is
100
SF,
Not
ice
the
drop
in d
esig
n pr
essu
res f
or th
is ca
se o
f a 1
00 S
F ro
of c
ompo
nent
, -20.
10-2
8.00
-1.1
021
.9 p
sf3(
-)
8.30
0.40
0.20
21.9
psf
3(+)
-20.
10-2
8.00
-1.1
021
.9 p
sf2(
-)
8.30
0.40
0.20
21.9
psf
2(+)
-15.
8023
.70
-0.9
021
.9 p
sf1(
-)
8.30
0.40
0.20
21.9
psf
1(+)
Usi
ng -G
Cpi
Usi
ng +
GC
piq z
zone
Des
ign
pres
sure
sG
Cpf
Vel
ocity
Pre
ssur
eB
uild
ing
Refe
renc
es.
Refe
renc
es.
1.A
mer
ican
Soc
iety
of C
ivil
Engi
neer
s, Pu
blic
atio
n A
SCE
7-02
, “M
inim
um
Des
ign
Load
s for
Bui
ldin
gs a
nd O
ther
Str
uctu
res”
, Was
hing
ton
DC
, 200
2;
2.W
. C. B
rack
en P
E, “
Win
d Lo
ad D
esig
n”, F
lori
da E
ngin
eeri
ng S
ocie
ty,
Talla
hass
ee, 2
007;
3.K
.C. M
ehta
, J.M
Del
ahey
, “G
uide
to th
e U
se o
f the
Win
d Lo
ad P
rovi
sions
of
ASC
E 7-
02”
ASC
E Pr
ess,
Was
hing
ton
DC
, 200
3.
