Author(s)

Y. Ariga

Abstract

Safety evaluation against surface earthquake faults is an important subject for long and large structures such as railways, highways, tunnels, banks, dams, and so forth. Normal faults, reverse faults, strike-slip faults and rotational faults, for instance, can be supposed in regard to the modes of surface faults. However, an analytical method for evaluating the safety against surface earthquake faults has not yet been established. So, I devised an evaluation method for safety against various modes of surface earthquake fault by applying a 3-D dynamic analysis method. Applicability of the method proposed was examined by the case study in regard to a concrete gravity dam. As a result, the discontinuous behavior of damfault- foundation system can be simulated by the method proposed. Vertical behavior of a dam by the normal fault or a reverse fault can be analyzed by inputting an acceleration wave in the vertical direction from the half of the rigid base of the 3-D FEM model. Horizontal behavior of the dam by a strike-slip fault can be analyzed by inputting an acceleration wave in the horizontal direction. Discontinuous behavior of the dam against various modes of surface faults can be simulated by combining a horizontal input and a vertical input of acceleration wave. Keywords: safety evaluation, surface fault, 3-D dynamic analysis, concrete dam. 1 Introduction The Upper Crystal Dam, the Upper Howell Dam, and the Old San Andreas were damaged by the surface displacement of the San Andreas Fault during the San Francisco Earthquake in 1906 [1, 2]. The Shih-Kang Dam was destroyed by the vertical relative displacement of about 7.6m during the Taiwan Chi-chi Earthquake in 1999 [3]. These historical cases show clearly that the safety

Keywords

safety evaluation, surface fault, 3-D dynamic analysis, concrete dam