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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
by Prutkova Eugenia and Ryabchenkov Sergei
The normative valueof wind pressure
Part I: Wind loads
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
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
by Prutkova Eugenia and Ryabchenkov Sergei
Figure 3: The scheme is used for collection loads of building
Part I: Wind loads
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
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
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
К1Н- value of cofficient К1 on height Н under ground level
(3)
Part I: Wind loads
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
0 1Н 2= K KH
The determination of the resulted wind loads, acting on buildings and
structures
Part I: Wind loads
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
( );
( );
( );
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
by Prutkova Eugenia and Ryabchenkov Sergei
(4)
Part I: Wind loads Figure 5: Level of pressure by streamlines of air flow
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
-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
by Prutkova Eugenia and Ryabchenkov Sergei
wind
micro-manometers
The determination of distributed wind loads, acting on surface of the
building
Part I: Wind loads
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
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
by Prutkova Eugenia and Ryabchenkov Sergei
(5)
(6)
Effects from wind loads
Part II
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
Part II: Effects from wind loads
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
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
by Prutkova Eugenia and Ryabchenkov Sergei
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
Part II: Effects from wind loads
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
(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
Part II: Effects from wind loads
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
(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
Part II: Effects from wind loads
measure of Glauert-Den Gartog
characteristics of the building
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
(11)
(12)
Part II: Effects from wind loads
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
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
Part II: Effects from wind loads
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
(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:
Part II: Effects from wind loads
0
2 210 1 2 0
1
2z
z a
dmV K K HL m G
d
otherwise :
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
(15)
(16)
Influence of wind loads on the exploitation
of the building
Part III
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
JASS-2006
by Prutkova Eugenia and Ryabchenkov Sergei
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
by Prutkova Eugenia and Ryabchenkov Sergei
Table 3: Dependence the level of discomfort from the value of acceleration
Part III: Influence of wind loads onthe exploitation of the building