Variational solution for the effect of vertical load on the lateral response of offshore piles

• An approach for effects of vertical loads on lateral response of piles is proposed.
• Pile responses are determined by using the principle of minimum potential energy.
• Disagreement existing between the analytical and numerical solution is explained.
• Influence of related parameters on lateral response of piles has been studied.

Pile foundations supporting offshore and coastal structures are usually simultaneously subjected to vertical loading from the superstructures and lateral loading due to wind or wave actions. An analytical model is presented to investigate the effects of vertical loads on the lateral responses of piles applied in such cases. In this model, the response of the soil is given by the fundamental Mindlin׳s solution for half-space subjected to both concentrated horizontal and vertical loads. The deformations and reaction pressures of the pile are represented by finite series. The responses of the pile are determined by using the principle of minimum potential energy. The proposed model is validated by comparison with the results of field load tests and laboratory load tests. The influence of related parameters including lateral load level, ratio of the vertical to the horizontal loads, pile slenderness ratio and pile flexibility factor has also been studied in this paper.