Seismic performance based design of reinforced earth

The seismic design of structures based on their expected performance is becoming very widespread in civil engineering, as it is reasonable to accept different levels of damage in proportion to the return period of the earthquake. This approach, however, is still little developed for composite and mixed works, such as for reinforced soil with geosynthetics; the subject itself is not properly encoded within European laws. This paper suggests some practical aspects to be considered in the seismic designing of geosynthetically- reinforced earth based on expected performance. Generally speaking, seismic design may be carried out according to different approaches, gradually increasing in complexity, from the pseudo-static to full dynamic. The purpose of these methods can be quite different: some purport to the study of the ultimate limit state, while others to the study of serviceability limit states. Nevertheless, all methods of analysis are routinely used without a proper distinction regarding the levels of accuracy in forecasting. In this paper, numerical modelling was used in order to study the seismic performance of geosynthetically-reinforced earth works under the effects of different earthquakes. The purpose was to quantify the reduction factor of PGA for global ductile behaviour of the structure. Consequently, lower pseudo-static forces may be used in a similar way as for concrete structure