Civil Engineering Reference
In-Depth Information
2
K
=+⋅
=+ ⋅ +⋅
8.7
5.7
M
(dB),
12
(9.43)
2
K
8.7
17.1
M
5.7
M
( dB),
13
where
M
is the logarithmic ratio
⎡
⎤
mass/area of element
j
(
⊥
i
)
M
=
lg
⎥
.
(9.44)
⎣
mass/area of element
i
It should be noted that these expressions are assumed to be frequency independent.
9.3.2.3
Some examples of D
v,ij
and K
ij
Expressions given in the standard EN 12354 are based on a number of measurement
results, both from laboratory experiments and from in situ observations. As expected,
data for massive, heavy constructions are more commonly available than for lightweight,
multilayered type of constructions. Estimating transmission along lightweight façades
may be a real challenge. One should expect that the amount of data will increase with a
prolonged use of prediction models such as given in EN 12354.
80
No layer
On upper side
On lower side
On both sides
70
60
50
40
125 mm
30
150 mm
7 mm
rubber
20
10
120 mm
0
63
125 250 500 1000 2000 4000
Frequency (Hz)
Figure 9.21
Measured vibration level differences in a test building of aerated aggregate concrete. Elastic layers
(foam rubber) between wall and floor slabs.
After Huse (1972).
