Rational and practical method for determination of seismic-induced earth pressure on non-yielding walls

Okabe and Mononobe proposed a pseudo-static method in late 1920s, the so-called Mononobe– Okabe (M–O) method, to determine the seismic-induced earth pressure (SIEP) on a wall. Because of its simplification and ease of use, this method has been widely used since its introduction. Since the M–O method is intended for yielding or flexible walls, it is questionable to extend it to non-yielding or massive walls such as bridge abutments. Due to the lack of a better method, engineers have the tendency to keep using the familiar M–O method, raising the concern on wall design safety. In the modern era, some authorities arbitrarily specified an unjustified constant SIEP value for designing a rigid/massive wall. Others advocated a fairly complex equation or numerical approach to handle the issue. This paper closely examines the suitability of the M–O method first, followed by the proposal of a rational and practical method for determining SIEP. The proposal method is verified by the finite element method. Effects of superstructure and various system parameters on SIEP are also discussed. The proposed method is particularly suitable for non-yielding walls with the rear face sloping downward away from the backfill.