Environmental considerations 207
powerful depth vibrator or a modification of the foundation method would
have to be considered. Vibration measurement can, by all means, serve as
preservation of evidence in order to prove the admissibility of vibrations.
In Figure 6.3 results of such direct vibration measurements are shown
from a project area in Berlin where vibro compaction was to be carried out
in loose-to-medium dense medium sand for the foundation of a housing
project. Buildings and commercial structures situated at the perimeter of
the foundation site were potentially exposed to the vibrations emanating
from the construction work. Vibro compaction was to be carried out with
two different depth vibrators operating at frequencies of 49.5 Hz (Type A)
0.1
1
10
100
10
100
1
Distance r (m)
PPV
G (mm/s)
Type B
0.1
1
10
100
10
100
1
Distance r (m)
PPV
G (mm/s)
Type A
Figure 6.3 Vibration measurement (PPV) in medium sand exposed to depth vibrator
vibrations. (Courtesy of GuD, Berlin, Germany.)