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1
DISPLACEMENT (m)
0.1
Morgan Hills
Kern County
Landers
El Centro
Loma Prieta
0.1
Michoacan Mexico
Saguenay *
Loma Prieta *
* from Lok & Riemer (1999)
and Riemer et al. (1996)
0.01
0.5 1.0 1.5 2.0 2.5
GMI=0.1
FACTOR OF SAFETY
GMI=0.2
GMI=0.3
GMI=0.4
1
DISPLACEMENT (ft)
Figure 7.7: Displacement versus Static, Post-earthquake Factor of Safety
The data in Figure 7.7 are broadly separated by ranges of the GMI factor. The width of the GMI
bands reflects the influence of site-specific factors such as the thickness of the potentially
liquefiable soils, the embankment geometry, and the characteristics of the ground motions. This
chart facilitates reasonable estimates for the lateral deformation of an embankment using the
post-earthquake factor of safety and the GMI value for the design level earthquake. Given the
factor of safety and the GMI value, a range of displacements is indicated. As a screening and
preliminary analysis tool, it is recommended that the mean displacement be selected (Figure 7.8).
The upper boundary for the representative GMI should be used for estimating the permanent
deformation for the following conditions: (a) thick layers of liquefiable soils, (b) tall
embankments, (c) seismic hazard consisting of ground motions with enhanced long-period
components, (d) seismic hazard involving near-fault conditions. A simplified design chart based
on the data in Figure 7.7 is shown in Figure 7.8.
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