Theme introduction and report on papers

Journal of Wind Engineering and Industrial Aerodynamics, 29 (1988) 3-17

3

Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands

THEME

I N T R O D U C T I O N AND R E P O R T ON P A P E R S

Carl K r a m e r Fachhochschule

Aachen,

Fluid Mechanics

Laboratory

and

Ingenieurgemeinschaft WSP

The

problem

structures as

has

of

wind

effects

on

e v i d e n t by the n u m b e r of p a p e r s

ference.

Whereas

at p r e v i o u s

d e v o t e d to this topic, about

areas of

I. W i n d

and

the

The

geometries

like p a r a p e t s

con-

3 sessions

important

and

low-rise

"main"

problem

load d i s t r i b u t i o n

and

designs which

equilibrate wind

accurate description

load d i s t r i b u t i o n on v a r i o u s investigates

the e f f e c t

of

low-rise

of

building

and canopies.

i m p o r t a n c e of this

weight

in this

are c o n c e r n e d w i t h

The three

and

researchers

only a few papers were

conference

in this a r e a f o c u s e s on the

load and the w i n d

structure add-ons

buildings

are as follows:

load and w i n d

wind

must

at the p r e s e n t

structures.

interest

Research

rise

and m o r e

on this s u b j e c t

conferences

20 % of all the c o n t r i b u t i o n s

buildings

low

lately b e e n a t t r a c t i n g m o r e

p r o b l e m area

lies

in the fact that

are c o m m o n l y a p p l i e d to loads by s t r u c t u r a l

low rise

forces

low

buildings

locally,

without

the a v e r a g i n g effects.

2. W i n d

load f l u c t u a t i o n s

Investigations

of w i n d

load f l u c t u a t i o n s

d e t e r m i n a t i o n of d y n a m i c r e s p o n s e components which

3. W i n d e f f e c t s on b u i l d i n s Here, roofing which,

we and

and

to the

building

in o r d e r to d e t e r m i n e

f a t i g u e effects.

components

see the w i n d e f f e c t s on b u i l d i n g c l a d d i n g elements,

due to t h e i r p r o p e r t i e s

flow field

important

and for b u i l d i n g s

are not p r o n e to v i b r a t i o n

the p o s s i b i l i t y of s t r u c t u r a l

are

and p o r o u s

and f u n c t i o n s

components insulation change

s u c h as blocks

the b u i l d i n g

locally or are s u b j e c t e d to a local f l o w f i e l d e q u i l i -

bration

process

Five

papers

three

paper

edges

The

gions

by T.

and

Kind

close

as

in F i g u r e an

pressure

taps.

The

similar

to

poulos H/W

those

other

buildings

Surry

and

base

i.

of

roof

of

Djakovich

tall

buildings"

by

of

the

with

wind on

and

b y E.D.

data than

our

own

and

own

data

building

H/W

spaced

height

loads

Jancauskas

= 0,17

forces

models"

on

canopies

and

J.D.

and

2.

and wind

building

is

Statho-

in F i g u r e

pressures

as

these

closer

researchers.

tall

"Wind

the less

verifies

with

shown

re-

(4) . In 1986,

his

heights

are

various

are

(3)

with

model

relative

suctions

(2)

Kind

other

flat

corner

example,

Colloquium

relative

by

on

by

in t h e

Stathopoulos

contours

(6)

pressure

Surry

R.

tunnel

with

dealing

area,

i.

For

and

Aachen

earlier

"Extreme

problem

reported

edges.

paper

wind

models

D.

roofs

Stathopoulos

In h i s

pressure

"Wind

especially

3rd

influence

papers are

data

reported

Typical

flat

measured

1978

building.

flrst

in c a t e g o r y

on

the

improved

investigated

= 0,5. Two

on

the

the

using

entitled

Stathopoulos

values

at

entire

the

in full.

falls

to

by

the

compared

presented results

presented

(i)

the

with

significantly,

published

presented

affect

5 deal

coefficients

regions

(5)

not

Stathopoulos

differ

as h i g h

results

be

corners"

pressure

previously half

shall

and

researchers

does

in s e s s i o n

of w h i c h

The roof

which

by D. at

the

Eddleston

(7). The

paper

studies

of

information is q u i t e ences

the

tion

of

facing

a

on

the

loading

the

the

wind

Due

vortex

load.

However,

case

maximum

important

to tall

by

the

the and the and

and

results minimum

wind

on

low r i s e

be

the

are

shown

on

of

(see

experi-

rise to

the

the of

buildposi-

building the

build-

but,

under

in d e t a i l

in t h e

paper,

buildings

may

in F i g u r e with

are

curtain Figure

increase 3.

a tall

4 concerning

distributions,

cladding,

buildings

is d u e

deals

in F i g u r e

pressure

finding

canopy

upstream

presented (6)

reported

decreased,

two

tunnel

comprehensive

high

surface

discussed

Djakovich

loading

This

the

on w i n d

a

the

for

building

between

results

The

buildings

load m a y are

gives

whereas

downwards.

wind

which

is b a s e d

and

canopies.

force

a smaller

system

Surry

on

streamline

to

Typical

model

low rise

wind

directed

canopy

paper

both

are

circumstances

ing.

for

For

dividing

wind.

standing

The

wind

directed

forces

ing w i t h certain

Eddleston

building

interesting.

the

and

isolated

an u p w a r d

ings

the

by Jancauskas

an

4).

build-

the also

walls, The

worst very etc.,

authors

5

/

,

x/h.

/

~0

x/h 3

"21 I'G

-0"4 -0"3

"~ •

"

-,1

""S

/

(b)

I I /

"0"5

-0"2

0-6

"~4

(a)

0

~ .~. 1-,.T -is

i (>8

,s .k

., ~' .,.i •

O~

~"

.;. d ~,

I.,

-,

\

x/h

• =

0-4

•

~ 0 3

0-2

,

o~s'

o.,

,.¢¢ / -o~s

•

.oa~

•

-o z3

¢ + d '"

. .

%~ '-" .°"

~

.o~

,o4

°2

© Height/Width

0

v~O

I

0.2

,

z/h

0-4

=

.2

i

0.6

Fig. 3. Comparison of mean pressure results of refs. 6 and 9. (a) Contours of mean pressure coefficient for low-rise building in built-up terrain; hp -- 0, from ref. 6 (crosshatching shows area with pressure taps in experiments of ref. 9). (b) Enlargement of cross-hatched portion of (a), including mean pressure coefficients measured in experiments of ref. 9: (e) pressure taps and Cp values of ref. 9; (c) pressure taps of ref. 6; (--) contours of ref. 6.

Figure I

(taken from KIND /5/)

6

U[ND PRESSURES Oil FLAT ROOF: EDGES AND CORNERS T.

STATHOPOULOS

Centre

for

Building

Studies,

Concordia

University,

Montreal,

Quebec,

H3G !ME',

(Canada)

xr~J/

C~) H:I"

C~) H = l'.,S-~

~T~2-~ .\.~2--"~-h

f

.F~/

>

-1"3

C~) H:3"

C~) H:3"

,

3-%

C~) H:3.~mf. ~-s 11 Height/Width

Fig. 4.

= I/6 and 3/6

Contours of mean pressure c o e f f i c i e n t s .

m
C~) H =1"

0"12 -~

...... 0-8" ~,~)

p if> ~ I

q pT-~c.;~s Q

0

,~ .~-

o,'S

c~

~:~'~

2.5 2.0

v 2,::

e~ C~ H =3°,~L Figure

Fig. 5.

Contours of instantaneous negative peak pressure c o e t f i c i e n t s .

WIND LOADS ON CANOPIES AT THE BASE OF TALL BUILDINGS

E.D. JANCAUSKAS and J.D. EDDLESTON Department of Civil & Systems Engineering, James Cook University of North Queensland, Townsville (Australia)

Fig. I Wind loading of attached canopies for B = 0° (a) Low h/hc (b) High h/b

b

d

5h

Fig. 2 Nomenclature

Fi@ure 3

3

tu u_

2

-----~

•

i -1°;/ tilHnNnHmn

PEAKDOWN

--

I

Q) 1

0

ABCDEFGH

C~=z o

0

-1 -2 0

-2

-3 30

60

90

WIND

Fig. 3(a)

120

DIRECTION,

Canopy load as a f u n c t i o n ation ( ~ = 4~0rm; 6 =

150

180

ABCDEFGH

0

CANOPY BAY

o f wind d i r e c t i o n

~0rn,

f o r the basic c o n f i g u r -

h e =~rtn i W 4 = ~ m )

(b) Distribution of peak upward load across the canopy for 8 = 90 ° (c) Distribution of peak downward load across the canopy for @ = 0 °

v

V -t.5

-1.0

CF z -1.2

~'~

-1.4

\\\ ",

I

HEIGHTOF UPSTREAMBUILDING(m) '~ 10 ~. 21 • 25 D 37 ~, 75

CF z .1.6

b

-1,7

"........

.

.1.8

-1.6

.i.9

.1.8

-2.0

~Noup ..... building

\b...// ~..~ I

-2,0

-2.1 -2.2

-2.2 10

20

30

40

SEPARATION BETWEEN BUILDINGS (metres)

•

.

,

20

•

.

,

•

40

.

,

•

.

60

80

UPSTREAMBUILDINGHEIGHT(melres)

Fig. 7. (a) Peak downward c o e f f i c i e n t as a f u n c t i o n o f the h e i g h t and l o c a t i o n o f an upstream b u i l d i n g , (b) maximum peak downward c o e f f i c i e n t as a f u n c t i o n o f upstream b u i l d i n g h e i g h t

Figure

3

(cont.)

EXTREME

SUCTIONS

ON TALL BUILDING

MODELS

D. Surry t and D. Djakovieh 2 Boundary Layer Wind Tunnel Laboratory, The University of Western Ontario, London, Ontario (Canada) ~Research Director, ~Graduate Student

MINIMUM

MINIMUM I 0

tl~,k " ~ . -TZf

-14~1

'

)-in~

~1

N/fi

,

-14

o,{

"-,.o \

i

i r-m

v

.1~ \

1

O!~ t, 3-~4( .s~'l I I

i

ttt

-7~\/ I I

L\I ....

-t4

.~ .76C'~I'

-Ib .J

I-zo

-3

,

I

'1 (o,.~ ,z/ ( ; ]

I'lZ-12

o/t t~< ~,!! \__AL (a)

(b)

(c)

(a)

(b)

(c)

i 3 , MINIMUM

MINIMUM

f

,6

-'~

~-,z

Q,.z0<

\v.,6Ji -fZ

....

/e.

) o'°o/ I<

)

r ~wl (a) Fig. I

(b)

(c)

(a)

(b)

(c)

P r e s s u r e coe[l~cient c o n t o u rs of w o r s t m i n i m u m v a l u e s [or all f o u r m o d e l s a n d for t h r e e t e r r a i n s ; (a) o p e n c o u n t r y , (b) s u b u r b a n a n d (c) u r b a n

Fi,~u r e 4

10

o ~ -q

o!----.~-:

-2:

:

-4J ...... TAPT. _,_

CRITICAL

T A P ~

(3)

5~'~ I

WIND

z

o

~

-2 4

~

~/.-| ~L//l-~"

/L.~]-J

.........

[.TAp3

-4 4 : T A ,P S i.

-50

0

:

Fig. 2

~

,.

;

,

i ' TAP 2

.4 4

,

j TA:L

-~ ,

i" TAPS

,--,

4

0 50 -50 0 50 FULL SCALE TIME (SECONDS)

An example of extreme peak Sklctions associated with complex local geometry

. . . . . . . . . . .

~

. . . . . . . . . . . . .

SUBURBAN -40

~

-2: 4:

~ .4L,.,

"

Fig. 7

o

...;T.A%

-20

0

20

40 -40 -20 0 20 40 -40 DIMENSIONLESS TIME tVH/B

URBAN ,

J

-20

'

L

0

,

T

20

•

1

40

Typica] pressure signals obtained from the same location (xJB = 0.3 I, z/H = 0.15) on the side parallel to the wind (n = 1)

Figure 4 (cont.)

ii

use

an

to

16

interesting pressure

the

pressure

on

one

of

certain

signals these

time

interesting large

coefficient Larger

This

may

Six

~cp/cp

be d u e

ins e d g e s ,

in

wind

detail

(i0)

for

cribed due

to

the

it

tests

and

shingles tiles the

local

session

paper,

concrete

edge

the

The

may

only

the

with

the

satisfactorily

a test

roofing

as

investigated group

is

des-

works,

which

to be

produces

a

a suction

zone

5).

our

earlier

the

shingle

From between

plywood

behind

substructure

for

plate

for

batten

whereas

space

procedure

reproduces

and roof-

to b u i l d i n g

mechanism

roof

in t h e

2 or

lead-

asphaltic

earlier

difference

describe

of

tile,

and

impermeable

of

changes.

later by our own

(Figure

is t h a t

over

vortices.

uplift

the

edge

a An

pressure

geometry

problem

in c i t e d

around

the

(8) r e l a t e s

and

The

as

coherent

of

at t h e y a w i n g

concerned

(9)

for

event.

in the o r d e r

separation

equilibrate

authors

are

tiles.

that

tests

are

the b u i l d i n g

are

shingle

is a w i n d

pressure

which

known

suctions

is a s i m i l a r

flow field

tile

peak value

accumulation

triggering

and Cermak

similarly

of t h e

A pre-set

"Wind resistance

Lamb

This

the

up

averaging

seperation

at the w i n d w a r d

normally

testing

underneath

f o r the

the d a m a g i n g

shingle

history

in

field. The

last

typical

roof

paper due

the

surface

b y H.J.

mean

of t h e

for

in d e t a i l

papers

are d e v o t e d

Nieman

6).

In a w i n d

and f l u c t u a t i n g

- calculation

author

of s t a t i c of

mean

and response (ii)

tunnel

response and

deals

This

response

of

of

a cantilevered a

grandstand

a 1:200

at the u p p e r

and

is a n e c e s s a r y

calculation

consists

of

with

study with

pressures

measured.

a comprehensive

calculation

"Loads

turbulence"

roof were

b y the

to the d y n a m i c a l

buildings.

to t h e w i n d

(see F i g u r e

model,

tion

two

low r i s e

The roof

-

zone

tiles.

the

and

is w e l l

the

flow

by Hazlewood

authors

leading

work,

local

this

loading.

clay

height where

examining and

The variations

occur

by Peterka,

by the

peak

to s t r o n g e r

The

in E u r o p e

stagnation the

in

the d a t a

after

the

per unit

rise

elements.

ing s h i n g l e s " element

is t h a t

to the

giving

papers

cladding

and

of the b u i l d i n g .

variations

of runs.

triggers

before

technique,

simultaneously

a number

over

finding

sampling

channels

channels

span

heights

3 %.

conditional

measuring

which

scale lower

informa-

is d e s c r i b e d

3 steps

response square

of q u a s i

static

response

to

back

]2 WIND F ~ I S T A N C E

OF ASPHA/]?IC ROOFING SHINGLES

J. A. p ~ l , G. D. LAMB 2 and J. E. 1 Professor of Civil Engineering, Fluid Mechanics and Wind Eh~gineerh~ Colorado State University,

Fort Collins,

2Research Engineer, Owens C o m i n g

Fiberglas,

3University Distinguished Professor, Colorado State University,

Progrmn,

Colorado, USA. Granville,

Ohio, USA.

Fluid Mechanics and Wind Engineering,

Foz~c Collins,

Colorado, USA.

j ~

Fig. i.

~pical shingle i in. = 2.54 c~.

Fig. 5.

Separation Flow R e g i o n ~

/~kocal

/ \

//

/

~

flow over a shingle.

Velocity

Measurement

1?18,,

1.0

ACp=Cp(bottom)-Cp(tOp)= Net Uplift Coefficient-,%~ //

0.8 0.6 0.4 c m

E

/ Cp(top)--.~ ~Xo /

Cp(bottom)\

"~

0.2

.......

~

0 -0.2

Cp:(P-Ps)/( O.5pVR2 )

-0.4 -0.6 -0.8

File U 12002_

('Flow

....

,, Tap

Fig. 6.

R LO

Pressure C o e f f i c i e n t s

/

.

:

---r-,

0cations on a s h i n g l e before u p l i f t .

Figure

5

13 LOADS AND RESPONSE OF A CANTILEVERED ROOF DUE TO WIND TURBULENCE H.-J. Niemann Professor D r . - I n g . ,

B u i l d i n g Aerodynamics Laboratory,

R u h r - U n i v e r s i t ~ t Bochum

I

~

I Pylon

(o) model cross-secfions,dmensionsin rnm

Q-G

-g

~

~-Smndsat~nd

133

[

(b) [eyou~of g~ands~andd~m~sionsn m Fig. I. Overall full-scale and model dimensions

The above considerations suggest, that the complete description of the wind load requires three sets of data: (i) (ii)

The static loads are determined in terms of mean pressure coefficients; The quasi-static load is given in terms of the covariance matrix or in a normalized manner by correlation coefficients Pkl: Ok] = Pkl" % ' ° I

(10)

( i i i ) The spectral densities, Spkk, of loads k and the Co-SDF, COpkI, of every two loads k and I as functions of frequency and point of attack.

Figure 6

]4

tube ¢) 325£ x 25

0]5

Mg 8.983

~'~")'~"

!

lump moss IPE 750xlZ,7 7"ZM9 ~. rz~68 26.161

toto{ moss: 20.068

Mg

(o) structural system

(b) mode I, fl = 2.434 Hz

(c) mode 2, 12= 2.603 Hz

Fig. 6. System and mode shapes

~yQ/?

GRF

compressive f o r c e in t e n s i o n bar, S

386 kN/kPa

1.21 - I u

1.30

1.93

t i p deflection of girder, w

5 cm/kPa

1.77 • I u

1.61

2.68

370 kNm/kPa

1.40 • I u

1.60

2.32

bending moment o f g i r d e r at suspension, M

qH - mean o f s t a g n a t i o n pressure a t r o o f top I u - turbulence i n t e n s i t y

a t r o o f top

Figure

6

(cont.)

15 AERODYNAMIC DAMPING AND S T I F F N E S S OF A SEMI-CIRCULAR ROOF IN T U R B U L E N T WIND D. J. Daw ~and A. G. Davenport 2 ~Civil Engineer, Acres International Ltd., Niagara Fails, Ontario (Canada) (formerly Graduate Student, The University of Western Ontario) =Director, Boundary Layer Wind Tunnel Laboratory, The University of Western Ontario, London, Ontario, (Canada) m~b

Xu..*l F~oot

~-7~'.."/ir~V /

<

/

Fig. 1 Side view ofsemi-elrcular cylindrical model with shaker mechanism

%.

%%

\\ ms'2 kg/m2 ~.S=5%

%

\ \ U,~-15 \ U. - zo \ i

i

%.

Arch Roof

U.- 10 m/s~ ~'~

ms=6

kg/m

/~ ]

/ Vacuum

"~ \\o..2o\

2

x i

10-3 Fig. 4

In

10-1 Frequency f

b

101

Dynamic magnificaUon curves for a typical a/r-supported structure and an arch roof, of smooth seml-circular shape in turbulent wind. with and without aeroelasdc forces included.

Fi@ure 7

(a)

- -

a,Jl'} 10.0

~ x

I-.OI~R,UM-g~S, I-.OI~R z-,oala -

,

z-01m

-

;.,o2sA. uN. T

z-.os~R a-.o21A z-.0ZSR~ SIIJ-AJF ~ .... z-.010a

*-.o~sR. u..~

I-.0STR-

SlIH'A~lt

ii)z.

/

,-.ol~R

/

/

z-.o11~ *-,o2m z-02SR z-,OS;R

/

/

Ou*,L-S1,*dy P',d~c"o', Sllll-Xl.

Fig. 2

S"tt- A¢,

I n-phase aeroelutlc eoetlicients of semLclrcular mode[, swaying in turbulen I winds expre~ecl u (a) aerodynamic mass Ind (b) aerodynamic stir'hess

cross

i- o l m ~ " I-.021R

l-,ols. 1.0Z 2m z-.O ~R

z-.OST~

,-.01$R

l-0ZSR I.,0$7R

,o i ..... .1 P-fR/U N Fig. 3

,or

\

,i f'-IRIU.

Aerodynamic damping coefficienLt for the oscillating semi.circuiar model. swaying in turbulent cross wind

Figure 7 (cont.)

17

ground turbulence

and

c a l c u l a t i o n of m e a n s q u a r e

-

The

paper,

c i r c u l a r roof

"Aerodynamic

is an e x p e r i m e n t a l

type

buildings

wind

tunnel

speed, A

which

measurements,

The r e l a t i o n comparison

gives

an

effect was

is

with

and

difference

without

result

is

level.

L IT E R A T U R E 1 2 3 4 5 6 7 8 9 i0 ii 12

e i t h e r by

air

(see F i g u r e

dome

supported

a

forced

the v a r i a t i o n of the

aero-

are e x p o s e d to

reduced frequency

or

reduced

amplitudes. and

arch-roof

possible

Reynolds-number line by a bar on

Whereas

A

wind

the s e p a r a t i o n

no i n f l u e n c e w a s f o u n d for the

aerodynamic

stiffness

aerodynamic damping

this d e f i n e d s e p a r a t i o n

line.

air-supported

already decreases

Davenport

cylindrical

air-supported structure

for the

that for the

magnification top

and the

semi-

For the

linear for small

the top of the structure.

a

7).

the m o d e l s

information.

of

D a w and A,G.

arch-roof

e l i m i n a t e d by d e f i n i n g

aerodynamic mass ficant

by D.J.

investigate

between

interesting

and s t i f f n e s s

can be r e a l i s e d

in o r d e r to

coefficients

response.

s t u d y on s e m i - c i r c u l a r

or by a light w e i g h t

oscillation elastic

damping

in t u r b u l e n t w i n d "

(12)

structures

of r e s o n a n t

at

there

is a

signi-

coefficients

A further

structure,

with

interesting the

lower w i n d v e l o c i t i e s

dynamic at roof