Retaining structures are susceptible to failure during strong earthquakes
and are damaged frequently. Such failures are documented in
almost all post-earthquake damage reports, e.g., the 1960 Chilean earthquake
damage reported on by Duke and Leeds (2), the 1964 Alaska
earthquake reported on by Ross, et al. (13), and the 1971 San Fernando
earthquake reported on by Clough and Fragaszy (1).
Many earthquake-damage surveys contain accounts of movement or
failure of bridge abutments due to the seismic lateral pressures. The wall
movement causes distortion or even collapse of the bridge superstructure.
Although this form of failure is not as dramatic as other types of
earthquake damage, the seismic behavior of earth retaining structures is
an important design problem in seismic regions.
Gravity retaining walls that support dry cohesionless backfills form a
major group of the earth retaining structures. These walls are damaged
during strong earthquakes because of seismically induced lateral earth
pressures and inertial effects on the wall itself. The present paper is concerned
mainly with the seismic behavior and design of these walls.
Two design methods are currently available for the seismic design of
gravity retaining walls. The first method, which has been the common
practice for many years, is based on design rules suggested in a paper
by Seed and Whitman (15). In their paper use is made of the MononobeOkabe
analysis which is an extension of the Coulomb sliding wedge theory
in which horizontal and vertical inertia terms take into account the
earthquake loading. In this method the design is controlled by a strength
criterion.
An alternative design method, which is based on the earthquake-induced
displacement of the wall was proposed by Richards and Elms (12)
in late 1970's. Richards and Elms suggest that an acceleration less than
the expected peak ground acceleration be used in design. This means