SPSI analysis of cement silos exposed to liquefaction

The paper presents some simplified SPSI methods, as well as static analysis and the effect of liquefaction. During the Hokkaido Nansei-Oki earthquake with a magnitude of 7.8, in Japan in 1993, liquefaction occurred on the filled soil in Hakodate Port. Of the 2 silos, one larger with a mass capacity of 5,000 t, and the other in the immediate vicinity, with a mass capacity of 2,500 t, the smaller experienced significant settlement and rotation. Due to local lateral spreading, 1/20 tilt and 90 cm differential settlement occurred. Cement silo with a mass capacity of 2,500 t was supported on 64 pre-stressed concrete piles. All piles experienced fracture. The damaged silo superstructure was urgently demolished, so as not to damage neighbouring buildings. Mori and Numata performed detailed analyses of piles of this silo, after demolition, including displacement, acceleration, shear stress, shear strain and excess pore water pressure ratio. The same authors also provide models of interaction with the spring system, such as Gazetas, Mylonakis, Tazoh, Novak, Nogami, Penzien, Wilson.