Recently, there are few construction works in vacant lot. Many construction works take place after demolishing the existing building. In such case, reuse of the existing piles is reasonable. We need a way to verify the performance of the existing piles for reuse. Therefore, in this paper, we proposed a simple method for estimating the static elastic pile-head spring using the impulse response excited by human power. We also proposed a simple method to simulate the impulse response of the pile-head.
The steps for the proposed estimation method are as follows:
1. Attach the accelerometer to the target pile-head.
2. Hit the pile-head with an impulse hammer to obtain the time series data of the input and response of the pile-head.
3. Calculate the impulse response of the pile-head by using the data.
4. Pile-head spring we want is the reciprocal of the impulse response.
Dynamic model proposed to simulate pile-head response is a beam-on-Winkler-foundation considering its own inertial force. Assuming homogeneous subgrade and applying some boundary conditions to the model, closed-form solutions of pile-head response can be obtained. By using these solutions, we can simulate the pile-head response easily.
As a verification examination, we compared results of the proposed methods with results of static load tests. We conducted the examination on a total of five piles at three locations. As a result, we confirmed that the results of proposed methods agree with the results of static load test.
