DYNAMIC ANALYSIS OF AN EMBANKMENT DAM MAKING USE OF INCREASED TIME STEPPING

Abstract eng:
Seismic design of embankment dams may include dynamic numerical analysis, which is commonly a time consuming task. The typically huge geometry of dams and relatively fine meshing required based on the input motion and geometry configurations, increase analyses costs. To avoid such computational severity, a previously defined convergence-based technique -which has successfully been utilized in numerous structural dynamic analyses- is examined in a geotechnical dynamic calculation. In this regard finite element analysis of an embankment dam located in a seismically active region is conducted using PLAXIS 2D 2016 code. The dam model is first evaluated by comparing the frequencies of initial natural vibration modes with those obtained from shear beam analysis. The strong ground motion events, recorded in the seismic zone were then selectively exerted on the dam via a set of primary dynamic analyses. To accurately model wave propogation, the calculation time step was defined small enogh based on material properties, element size and sampling frequency of digital records of input motion. The time-consuming primary analyses were then repeated, here called secondary analyses, making use of input motions digitized with larger time steps. The increase of time step size in these secondary analyses is based on a new convergence-based redefinition of digitized excitation technique. The results of the primary and secondary analyses are satisfactorily similar; the decrease of the computational cost is noticeable, while the sacrifice of precision is negligible.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket