On the Issue of Dynamic Coefficients in Seismic Impact Problems

Abstract

In the first issue of ACADEMIA journal in 2019, an article "Dynamic coefficients or spectra of reactions (responses) of structures to seismic effects?" was published. In the article it was noted that the outdated concept of "dynamic coefficient" continues to be used in the Russian Federation Code.

But in none of the of the Russian Federation seismic Code (SP 14.13330.2018, SP 268.1325800.2016, etc.) there is no definition of this concept. The authors of the project of Code 14.13330.2019 tried to fill this gap and to determine the dynamic coefficient through static displacement during an earthquake.

We believe that such a definition does not have physical meaning. For a seismic impact it is impossible to correctly determine the static impact which must be multiplied by the dynamic coefficient. It does not define anything and, most likely, is entered into the text only for the sake of formal filling of the corresponding section. The presence of such meaningless concept in normative documents impedes normal work on improving the regulatory framework and can not only divert one from understanding the phenomenon, but also lead to incorrect decisions.

We propose to exclude "dynamic coefficients" from the Russian codes relating to seismic effects and replace them with response spectra. This article, is devoted to the rationale for this proposal.

The concept of response spectra is recognized throughout the world, including Russia. It is known that the number of countries where this concept is used in the national codes is more than fifty.

After the publication of the article "Dynamic coefficients or spectra of reactions (responses) of structures to seismic effects?" we received many reviews, both from designers and from well- known scientists who were affected by the topic that we raised. Therefore, we consider it necessary to continue its discussion.