The Use of Limestone Sand for the Seismic Base Isolation of Structures

<div>(a) First period of free oscillation of the columns determined after the end of each base excitation. (b) Normalized stiffness of the columns after the end of each successive base excitation.</div>

Advances in Civil Engineering

fig12

Figure 12

Figure 12: The Use of Limestone Sand for the Seismic Base Isolation of Structures 