Action 6.3 : A better representation of the seismic motion for the engineers

State of the art / Background knowledge:

The representation of the seismic motion is nowadays mainly based either on response spectra or on Time Histories (THs). The use of response spectrum comes from its very convenient and versatile use by the structural/mechanical engineers by mid-1900. Complementarily, its simple form make it, at first, quite straightforward to compare several seismic motion in order to evaluate the more demanding one. Thus, response spectra was widely adopted by Regulators as the representation of the seismic motion that structures and equipment shall take into account in their design. As of now, it is still widely used in various international and national codes, completed with additional information to derive time histories if needed.

Limitations of current practice or knowledge (i.e. technological barrier):

However, development of computation capacities and codes tends to give access to more evolved methods for representing the seismic motion and for modelling the structural/mechanical response.

Program of research

The aim is:

  1. To investigate the potential of new approaches to evaluate the dynamic response of structures and its need in terms of definition of the seismic movement. The Random Vibration Theory is such a candidate,
  2. In link with SIGMA2 Work-Package 3, to evaluate the possibility to use or to develop adequate Ground Motion Parameters’ Equations (GMPEs) in line with the first objective.

Work plan includes 3 main topics:

  1. To make some bibliography on the use of RVT for the propagation of the seismic motion into a mechanical system,
  2. To investigate any potential methods with similar principles to RVT: use of an advanced seismic motion representation (e.g. Power Spectra Density or Fourier Amplitude Spectra) in a method transferring itself directly at various location of interest into a building,
  3. To perform study cases in order to compare:
  • the use of RVT for evaluating the seismic response of buildings, taking into account Soil-Structure Interaction (SSI) and the need to access to various levels of confidence,
  • More traditional approaches using THs and resolution in the frequency domain.

The deliverable is a report synthesizing:

  • The bibliography relative to the RVT and other similar methods,
  • The results of the study cases.


  • Type: Internship
  • Collaboration:
  • Status: In progress (started 2018)