ABSTRACT
Block vibration tests were conducted on two test blocks measuring 3.0m × 1.5m × 0.7m and 1.5m × 0.75m × 0.70m, cast on level ground. The blocks were excited into vertical vibrations and the amplitudes of vibration at different frequencies of excitation were measured using acceleration transducers mounted on appropriate faces of the block. Dynamic shear modulus at this site was also determined by conducting in-situ tests. The natural frequencies and the vibration amplitudes of the test blocks were calculated by (i) the linear spring method, (ii) the elastic half space method and (iii) the impedance function method. A comparison was then made of the observed and computed natural frequencies and the vibration amplitudes of the blocks. The results of this comparison showed that for the cases of vertical vibrations, the natural frequencies in this case could be reasonably predicted by either of the methods used. The calculated and observed amplitudes, however, showed a wide variation.
