Two different analysis types are possible in DReW Seismic: these are "Dynamic" and "Pseudostatic".
Analysis type
The dynamic analysis, which represents the main feature of DReW Seismic, is an innovative calculation that allows predicting the evolution of the horizontal displacement of the top of a cantilever embedded retaining wall due to an earthquake. As required by the design codes of many countries, this analysis represents a more rational approach than the simple calculation of the safety factor of these structures. Indeed, this approach is required by many national standards as well as Eurocodes, such as in particular, Eurocode 7 Part 1 (§2.4.8, §9.8.2) and Eurocode 8 Part 5 (§7.1(1)P, §7.1(2)).
The dynamic analysis employs the method developed by Conte, Pugliese and Troncone (2022). The calculation procedure is summarized here. The results provided by this type of analysis are:
•displacement time-history owing to a given earthquake. The displacement is calculated for the top of the wall
•comparison between the ground acceleration time-history and the corresponding critical threshold, which is also updated during the earthquake
•evolution with time of the angular acceleration of the wall
•evolution with time of the angular velocity of the wall
•evolution with time of the rotation of the wall
•evolution with time of the net pressure at the wall end and comparison of this latter with the corresponding limit value
•evolution with time of the depth "X", which defines the portion of the soil in which the passive resistance is completely mobilized
•evolution with time of the center of rotation of the wall "Y"
•evolution with time and depth of the net pressure acting on the wall
For the sake of completeness, a pseudostatic calculation can be also performed. In this case, the method developed by Conte, Troncone and Vena (2017) is employed, which is based on a distribution of the stresses acting on the wall that is more realistic than the ones assumed in classical methods. The results provided by the pseudostatic analysis are:
•net pressure acting on the wall
•shear force
•bending moment
The default option for analysis type is Dynamic.