Rotation of large gravity walls on rigid foundations under seismic loading

A pseudo-static model is developed for the prediction of permanent residual displacement of monolithic retaining walls in rocking. The model follows a Newmark approach, and is validated by comparison with experimental data of the behaviour of a large gravity wall subject to earthquake shaking. The experimental data show that rocking of retaining walls comprises two components, an elastic recoverable element and a permanent or residual component. The rocking model showed good agreement with the observed data, matching the total displacement closely after a series of five earthquakes. Comparison with conventional design approaches suggests that there is opportunity to reduce conservatism in the design of gravity walls prone to rocking by using a mechanism-specific model for the wall behaviour, particularly where the nature of the earthquake input motion can be defined.