Geotechnical Seismic Isolation
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acceleration was beyond around 0.11g, implying a static friction coefficient of 0.11. After the table acceleration exceeded 0.11g, the transmitted acceleration was maintained at around 0.08g regardless of frequency, indicating a dynamic friction coefficient of 0.08. Moreover, larger slip displacements were resulted from lower excitation frequencies (Figure 7).
Transmitted Acceleration (g)
0.3 0.25 0.2 0.15 0.1 0.05 0 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Table Acceleration (g)
Figure 6. Variation of transmitted acceleration with table acceleration from rigid block tests on geotextile/UHMWPE interface under harmonic excitations (Yegian and Kadakal, 2004). 5 1 Hz Slip Displacement (cm)
4
2 Hz 3 Hz 4 Hz
3
5 Hz
2
1
0 0
0.2
0.4
0.6
0.8
1
Table Acceleration (g)
Figure 7. Variation of slip displacement with table acceleration from rigid block tests on geotextile/UHMWPE interface under harmonic excitations (Yegian and Kadakal, 2004).