2024 年 10 巻 36 号 p. 1389-1394
Pier is a key member in the bridge structure as it must transfer superstructure loads to the foundation safely. However, there is always risk of it getting damaged under the events of ground excitations and this makes researchers find new ways of designing a ductile, lightweight, and economical pier along with its foundation. This study presents such a pier consisting of multiple steel pipes integrated by shear links. It is supported by either a conventional pile group foundation with a footing (F-type) or by connecting column pipes directly to piles interconnected by an underground beam (S-type). The study focuses on the dynamic soil-structure interaction to determine the influence of kinematic and inertial effects on the behaviour of both types of structures. A series of dynamic simulations are conducted by using a sinusoidal wave of amplitude 200 gal and frequency of 2Hz. Comparison of pile’s response at key instances such as corresponding to maxima of inertia, ground deformation and pile head bending moment identifies the influence of kinematic and inertial action. The qualitative action of inertia force and far-field ground deformations is established by applying inertia force and ground deformation profile as loadings in separate static analysis. A match of correlation of inertial or kinematic action with corresponding dynamic analysis determines the dominant action. The contribution of kinematic action towards pile moment is discovered by the dynamic analysis without superstructural mass and columns. Kinematic action has a maximum contribution of 30% only towards pile bending moment for D-S and 17% for D-F type. Inertial action is determined as most influential for both types of structures for an input motion of 2Hz; however, the kinematic action should be deemed serious as well due to the similar direction of action of inertia and earth pressure in F-type structures.
