ABSTRACT A vibration isolation system using spring units and visco ...

5.3 Comparison of the shaking table test and the simulation
5.3.1 Vibration properties
The natural frequencies are in both cases very similar. The amplitude of the simulation is a little
smaller than that of the shaking table test.
5.3.2 Seismic excitation
The Y direction response time history for the three dimensional Taft wave excitation is shown in
Fig. 17. The amplitudes of the simulation are smaller than those of the table test. But acceleration
and displacement are very similar. The similarity confirms the accuracy of the model.
The maximum response acceleration ratio of the model at the maximum acceleration of the
shaking table is shown in Table 4. In the cases of El Centro wave and Hachinohe wave the results
are for one dimensional excitation. In the case of Taft wave those are for one, two and three
dimensional excitation.
The response acceleration ratio increased only a little bit horizontally, but vertically more for the
three dimensional excitation than for the two dimensional one.
Fig. 17 Y-direction time history response (for TAFT 3-D) Table 4 Maximum acceleration response amplitude
6. CONCLUSION
A four story building was designed and certified for the maximum response. From our
investigations the following can be concluded.
1) In the vibration isolated building supported by springs and visco-elastic dampers vibration and
structure borne noise levels caused by traffic will be effectively reduced.
2) The characteristics of the dampers can be modelled properly by a 4 parameter model
respectively those of the springs by a multi-direction shear spring.
3) The 3 dimensional analysis of the models shows a good coincidence with the shaking table test,
so that it can be used for analyzing a real building with a vibration isolation system.