2019 Volume 75 Issue 1 Pages 35-48
In this study, we tried to evaluate the durability of wooden piles which have been applied to structure foundations and were constructed at approx. 100 years ago. The objective wooden piles have been located in sandy strata and above water table. In order to evaluate the durability, we conducted the visible confirmation of wooden pile surfaces, the soil investigations around wooden piles, and pilodyn tests. Furthermore, in order to confirm the strength and the bearing capacity, we conducted the uni-axial compressive tests of sampled wooden piles, the vertical compressive tests for cubic cut specimens of wooden piles, and vertical loading tests.
According to these test results, we can confirm that the wooden piles are sound excluding approx. 1.5m from the pile head and good enough to have the strength and the bearing capacity to the design value set at the time of construction. The wooden piles have been above water table for more than 90 years, are made of pines whose water content is 45-80%. And the soil around them are sandy soil whose fine-grained fraction content is 15-25%, and natural water content is 20-30%. These results indicate that the wooden piles which have the similar characteristics and exist in similar conditions would not be severely deteriorated.