Use of Bouc-Wen model for seismic analysis of concrete piles

Single concrete piles subjected to free field motion and ground lateral spreading are studied using the beam on Winkler foundation method. Soil loads on the pile are modeled based on nonlinear soil springs combined with a distributed viscous dashpot placed in parallel. These springs and dashpots are modeled using the modified Bouc-Wen model, which is also used to incorporate the variation of the pile stiffness beyond cracking loads. Three numerical examples are presented to study the importance of taking the concrete cracking effect into account in concrete pile analysis. Comparison of the predicted results with available test results shows that the presented method accurately modeled the static and seismic concrete pile behavior.