Environmental Engineering Reference
In-Depth Information
shock waves plays the most important role for the damage of buildings. The writer
designed an experiment of nitro n-butyl nitrate for buildings
'
damage.
Figure
2.31
indicates that
the damage of
n-butyl nitrate to brick structure
building is very clear/obvious. When tþ=T
þ
=
T
10, the damage of air shock waves to
building is determined by the super pressure of shock waves.
The positive pressure action time t
+
in the explosion of liquid explosive is very
long. The boundary conditions of buildings to explosion center is a topic which is
worth the study. According to energy conservation law:
r
BW
r
h
p
3E
q
R ¼
ð
2
:
93
Þ
Here, R is the distance of one building to explosion center; E is the elastic
modulus of building materials;
˃
is the stress of building materials;
ˁ
is the density
of building materials; B is a coef
cient; and W is the mass of an explosive.
], the resulted R is the
nearest distance with building not being damaged, or safe distance. If the stress is
replaced by limit strength
If the stress
˃
in Eq.
2.93
is replaced by allowance stress [
˃
˃
B, the resulted R is the destruction range. Table
2.4
lists
the limited strengths of common construction materials.
Table 2.4
˃
B
, E, and volume
-
weight values
ʳ
of construction materials
E (kg/m
2
)
˃
B
(kg/m
2
)
Volume
-
weight
ʳ
(kg/m
3
)
Materials
10
9
3
×
10
6
Wood
600
10
9
10
6
Concrete
2
×
5
×
2,600
10
10
10
6
Steel
2
×
2
×
7,800
Table 2.5 k values of several objectives
Objectives
k
Damage degree
Plane
1
Complete damage of airplanes
Locomotive
4
-
6
Ship
0.44
Damage of buildings on a ship
Nonarmored ship
0.375
Damage of ships (W < 400 kg)
Assembly glass
7
9
Broken into pieces
-
Wood siding wall
0.7
Damage (W > 250 kg)
q
, h is the thickness of wall with unit
Anil wall
0.4
Breaches (R
¼
k
m, W > 250 kg)
Anil wall
0.6
Cracks
Non
rm wood
-
stone
buildings
2.0
Damage
Concrete all
0.25
Severe damage
