Comparaison entre calculs de vuln\'erabilit\'e sismique et propri\'et\'es dynamiques mesur\'ees

TL;DR

This study compares seismic vulnerability calculations with measured dynamic properties of buildings, highlighting discrepancies and suggesting ambient vibration recordings as a calibration tool.

Contribution

It provides an experimental comparison between theoretical resonance frequency formulas and actual measurements for diverse buildings.

Findings

Variability in resonance frequencies is underestimated by formulas.

Type and height are significant factors affecting frequencies.

Ambient vibrations can help calibrate capacity curves for better accuracy.

Abstract

Large-scale seismic vulnerability assessment methods use simplified formulas and curves, often without providing uncertainties. They are seldom compared to experimental data. Therefore, we recorded ambient vibrations and estimated modal parameters (resonance frequencies, modal shapes and damping) of 60 buildings in Grenoble (France) of various types (masonry and reinforced concrete). The knowledge of resonance frequencies in the linear domain is essential in the seismic design. Hence, we compared resonance frequency formulas given in the design code with this experimental data. The variability is underestimated and only two parameters (type and height of the building) seem to be statistically significant. Moreover, we compared the linear part of capacity curves used in European Risk-UE method to the measured frequencies. The variability is still very large and these curve are often not relevant for the French buildings. As a result, ambient vibration recordings may become an interesting tool in order to calibrate the linear part of capacity curves.