Online-estimation of vibratory driven piles’ bearing capacity: a first approach

Bearing capacity is an important attribute of driven piles. For centuries pile hammers have been used and their number of blows can be interpreted with respect to piles’ bearing capacity and soil characteristics. However, currently no method exists to interpret process parameters of vibratory pile driving with respect to a pile’s bearing capacity. In a first step laboratory piling experiments using a vibrator and a hammer are carried out. The bearing capacities of the used model piles are determined by static load tests and secondary pile hammerings. In a second step large-scale piling experiments are carried out to enlarge and verify the results of the laboratory tests. For these experiments piles of different lengths have been driven using a diesel hammer and a vibrator. Apart from usual vibratory pile driving parameters the acceleration and the force between vibrator and clamping device are measured in realtime. Based on this data a specific driving energy can be determined and interpreted as a number of blows of a pile hammer. This allows the online-estimation of a vibratory driven pile’s bearing capacity