Estimation of Young's Modulus of Buried Timber Piles by Bending Vibration

Abstract

The vibration method with additional mass (VAM), by which the mass of a specimen can be obtained without weighing the specimen, was applied to buried timber piles to develop a simple testing method to estimate the deterioration of a buried timber pile. Small, clear rectangular bars with dimensions of 25 mm (Radial) × 5 - 25 mm (Tangential) × 275 mm (Longitudinal, span) and timber piles with a diameter of 140 mm and length of 4000 mm were used as the specimens. Bending vibration tests were implemented on the small, clear rectangular bars and timber piles with and without a concentrated mass. In the vibration test, the 1000-mm length part from the pile head emerged from the ground. The timber piles were not seriouly deteriorated during burying. The degree of ideality of the end condition (DI) of the timber pile at the initial stage could be used for about 10 years after burying. The estimation accuracy of the VAM was affected by DI and was improved based on DI. A simple method was proposed for the onsite estimation of the mass of a timber pile using the VAM. The uniformity of the ground could be estimated using the vibration test.