Experiment of demolition method of foundation for reusing existing piles

What is it about?

In case of reusing only existing piles other than foundation, it is necessary to select a demolition method of the foundation that doesn’t damage the piles. There is no study to examine the relation between the extent of the pile damage and the working efficiency in the demolition method. This paper describes the experiments of the relation using the foundations and the piles of building under demolition. The method with cutter is the most reasonable because its working efficiency is equivalent to the method with crusher and its effect on the pile soundness is equivalent to the method with wire-saw.

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Why is it important?

The demolition methods examined were crushing demolition, which has excellent workability using a crusher and breaker, demolition with a wire saw, which is less likely to damage the pile, and demolition with a cutter, which has both of these features. For underground beams, the crushing demolition and the demolition with cutter were equivalent in terms of workability and influence on the integrity of the existing piles. As for the pile caps, it was confirmed that the dismantling with cutters was the most reasonable method, although the effect on the integrity of the existing piles was small as in the case of the dismantling with wire saws, but the workability was not significantly different from the dismantling with crushing. In some cases, pile tests are conducted before demolition of buildings in order to utilize existing piles, but the results are different from those obtained after demolition because of the difference in the method of testing. The results of the seismic waveforms obtained before and after dismantlement were compared, and it was shown that the waveforms before dismantlement were characterized by the presence of the pile cap and the impact input at the bottom of the test hole in the pile body, but they did not affect the damage evaluation of the piles.