Prutkova Eugenia and Ryabchenkov Sergei Represent Report on the theme: JASS-2006

Prutkova Eugenia and Ryabchenkov Sergei

Represent

Report on the theme:

JASS-2006

The wind loadsin building

Presented on JASS – 2006, Saint-Petersburg

JASS-2006

Part I: Wind loads

Content

JASS-2006

by Prutkova Eugenia and Ryabchenkov Sergei

Part II: Effects from wind loads Part III: Influence of wind loads on the

exploitation of the building

Wind loads

Part I

JASS-2006


The normative valueof wind pressure

Part I: Wind loads

JASS-2006


Part I: Wind loads Figure 1: Map of wind zoning

JASS-2006

Part I: Wind loads

Figure 2: Map of wind zoning (part)

JASS-2006

Table 1: Calculated values of wind pressure on the height of buildings

Height, meters Coefficient K for city’s

≤5 0.4

10 0.4

20 0.55

40 0.8

60 0.8

80 1.0

100 1.15

Part I: Wind loads

JASS-2006


Figure 3: The scheme is used for collection loads of building

Part I: Wind loads

JASS-2006


the coefficient of dependability is:1,4f

The averaging interval 10 min 2 min 1 min 10 sec 3 sec

The correction coefficient on the average speed K1

1,00 1,10 1,15 1,29 1,41

The correction coefficient on the average wind

pressure К2

1,00 1,21 1,32 1,66 1,99

0 1 2*= K K - the normative value of wind pressure at the level of 10 metres over the surface of the ground, which corresponds 10-min. interval of averaging.

(2)

0

Part I: Wind loads

Table 2: Dependence coefficients K1 and K2 from averaging interval

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К1Н- value of cofficient К1 on height Н under ground level

(3)

Part I: Wind loads

JASS-2006


0 1Н 2= K KH

The determination of the resulted wind loads, acting on buildings and

structures

Part I: Wind loads

JASS-2006


( );

( );

( );

x H x

y H y

z H z

F L C

F B C

F H C

2

2

2

( );

( );

( );

x H x

y H y

z H z

M L m

M B m

M H m

Figure 4: The design scheme for tall buildings

forces from action of the wind, according to the axes X,Y,Z

moments, caused action of the wind, about this axes

Wind

Part I: Wind loads

JASS-2006


(4)

Part I: Wind loads Figure 5: Level of pressure by streamlines of air flow

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-1

1

relative dimensionlessvalue of the

pression

relative unit of length

windre

lati

ve u

nit o

f le

ngth

Some words about aerodynamic tube

Part I: Wind loads

Figure 6: The principal scheme of aerodynamic tube

JASS-2006


wind

micro-manometers

The determination of distributed wind loads, acting on surface of the

building

Part I: Wind loads

JASS-2006


p p1C = C + 1

p H pF S C

Ср1 - the absolute peak (maximum) meaning of the coefficient rarefaction on the surface of the building

S – the square of the element

Part I: Wind loads

JASS-2006


(5)

(6)

Effects from wind loads

Part II

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Part II: Effects from wind loads

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Resonance cases

N - the frequency of break-down vortex, in Hertz ; D - the specific size of object ;V - the speed of incoming air flow ;Sh - is determinated of the shape by traversal sectional

view of streamlined building, the angle of incoming air flow α

N DSh

V

(7)

GallopingPart II: Effects

from wind loads

JASS-2006


movement

wind

Figure 7: The principal scheme of ”Galloping” case

- selfrelative constructional damping action; - frequency of the self oscillations of the building; - the density of the air;V - the velocity of the incoming flow;В - the specific size of traversal sectional view of the building; - the speed movement of the element of the building in the

direction, perpendicularly to the speed V; - coefficients of the elevating forces and resistance of the

element of the building in axes, connected with the resulted speed vector of air flow (figure 8).

12

2L

D

dCm VB C y

d

dyy

dt

V LC DC


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(8)

Figure 8: Cross-section of elastic-fixed body

measure Glauert-Den Gartog

0LD

dCC

d

sin cos

cos sin

L x y

D x y

C C C

C C C

The connection CL and CD with final speed vector of the air flow


JASS-2006


(9)

(10)

vx

v v

y y

x x

12 0

2L

D

dCm VB C

d

From this two formulas the extreme meaning of the speed V could be found, which starts the condition

of galloping:

4k

LD

mV

dCB C

d


measure of Glauert-Den Gartog

characteristics of the building

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(11)

(12)


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DivergencyFigure 9: Collapse of Tacoma bridge

2H z aw HL m G

210 1 2

1

2Hw V K K - the normative value of the speed pressure at the height of building H,

- the angle of coming to the building air flow,- the change of the angle due to the

intertwisting of the building,- the stiffness coefficient of the building in

the case of twisting

0

aG

0

0z

z z

dmm m

d


JASS-2006


(13)

(14)

0

2 210 1 2 0

2 210 1 2

12

12

z

za

V K K HL m

dmG V K K HL

d

according to this the change of the angle can be found:


0

2 210 1 2 0

1

2z

z a

dmV K K HL m G

d

otherwise :

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(15)

(16)

Influence of wind loads on the exploitation

of the building

Part III

JASS-2006


JASS-2006


Figure 10: The scheme of tall building

movement

wind

Part III: Influence of wind loads onthe exploitation of the building

The level of discomfort.oscillations:

acceleration (in percent from acceleration gravity force)

insensible 0,5

appreciable 0,5 – 1,5

stimulated 1,5 – 5

extremely stimulated 5 – 15

intolerable >15

JASS-2006


Table 3: Dependence the level of discomfort from the value of acceleration

Part III: Influence of wind loads onthe exploitation of the building

Documents

Prutkova Eugenia and Ryabchenkov Sergei Represent Report on the theme: JASS-2006