Foundation Damage of Structures

Abstract

ABSTRACT The 1995 Hyogoken-Nambu earthquake caused heavy damage to many super- and sub-structures of elevated highways in the Kobe, Ashiya, and Nishinomiya area. The majority of the elevated highways are founded on piles, most of which are cast-in-place reinforced large diameter concrete bored piles. The bore-hole television (BHTV) system was the most reliable method applied to the inspection of the soundness of cast-in-place bored piles. It was revealed that some cracks occur not only around the top of a pile but also between the pile top and tip. It was also noted that the degree of pile damage does not necessarily correspond to that of super- and sub-structures. In addition, the lateral resistance of damaged piles is discussed herein, based on the results of an available full-scale static load test on a pile group. Some case histories of raft foundations, caisson foundations, steel pipe pile foundations and precast prestressed concrete pile foundations are presented. Finally, it was concluded that the foundation damage to structures is sometimes caused not only by seismic force of super- and sub-structures, but also by liquefaction and/or lateral flow of the subsoil below the ground surface.