Buckling stress of slender piles with rotational restraint at the pile head in liquefied soil

In our previous paper, the possibility of flexural buckling of slender piles in liquefied soil was presented, and then the boundary conditions are assumed to be ideal such as pinned or fixed end. The rotational deformation of the pile heads is, however, restrained by the footing beams in the real structures. Therefore, the boundary condition should be assumed to be arbitrary rotational spring. In this paper, flexural buckling behavior of the steel piles with rotational spring in the liquefied soil during earthquakes is clarified, and the buckling stress of piles with the soil-pile interaction is estimated by the design codes using modified equivalent slenderness ratio.