Identification and application of locally updated nonlinear damping models for reinforced concrete beams

Abstract

By studying the position and magnitude of earthquakes, that hit the French territory between 1962 and 2020, in parallel with the location of nuclear power plants that are among the structures at risk, a correlation can be found. So, standards have been developed to consider the seismic risk in structure dimensioning. Particularly, since May 1, 2011, new zoning of the French territory has existed. However, because some French regions were not considered at risk before 2011, structures were not designed to meet seismic standards. Today, to ensure the resistance of risk structures or extend their lifespan, it is necessary to perform new fine computations.

Particularly, in the case of reinforced concrete structures, the EC8 requires that the energy dissipations occurring in the structural elements are correctly described when nonlinear time history analyses are performed. However, the classical viscous damping models, classically used, are not based on physical considerations. That is why this paper aims to evaluate effective damping ratio transient variations as functions of variables representative of nonlinear behaviour. Then, those functions are re-used to develop a physic-based and locally updated nonlinear damping model for cracked reinforced concrete beams.