Vertical and combined loading tests for sheet pile foundation

The authors proposed a new foundation-type, named sheet pile foundation, which combines a footing with sheet piles. Sheet pile foundation can be constructed more economically than pile foundation, and can be applied to wider ground conditions than shallow foundations. To investigate the fundamental characteristics of the sheet pile foundation, a series of static loading tests were conducted on both shallow foundation and sheet pile foundation. Two different loading procedures – vertical loading and combined loading – were implemented. The combined loading tests can simulate earthquake conditions by applying the horizontal force and moment caused by the inertia of a superstructure while maintaining an appropriate vertical dead load. The model tests were conducted in a 1g gravitational field using model ground with the plane strain condition. To satisfy the similitude of the model, the relative ratios of bending rigidity for the sheet piles and the ground rigidity were taken into consideration. It was shown that the sheet pile foundation offers outstanding performance in terms of both bearing capacity and earthquake resistance. In addition, it was clarified that the axial force of the sheet piles provided a strong resistive effect under the combined loading condition during an earthquake.