Comparison of static lateral behavior of three pile group configurations using three-dimensional finite element modeling

The lateral resistance of three pile group configurations was investigated using three dimensional (3-D) finite element modeling. The three pile groups considered in the study were a vertical pile group, a battered pile group, and a mix of vertical and battered piles in a group. The study was motivated by the full-scale static load test that was conducted on the M19 pier foundation in the I-10 twin span bridge in Louisiana. The static lateral resistance of the M19 battered pile group was investigated previously using a 3-D finite element simulation and verified with the aid of experimental results. In the present study, the M19 battered pile group model was used as the basis for the vertical and mixed pile groups for developing their 3-D finite element models. The nonlinear material behavior was accounted for using elastoplastic constitutive models such as the concrete damaged plasticity model and the anisotropic modified Cam clay model. The lateral resistance of the pile groups was investigated in terms of load-displacement, axial load, bending moment, pile damage, soil resistance, and p-multipliers. The results show that the battered pile group had the largest lateral resistance, followed by the mixed and vertical pile groups, respectively. The largest lateral load share was carried by the two middle rows in the battered pile group, while it was in the leading row in the vertical and mixed pile groups. The soil resistance profiles show that the vertical pile group mobilized greater soil resistance than the battered and mixed pile groups at the same lateral load. The back-calculated p-multipliers are the highest in the battered pile group case, followed by the mixed and vertical pile groups, respectively.