Estimation of Natural Frequencies During Earthquakes

This paper presents two different recursive prediction error method (RPEM} implementations of multivariate Auto-Regressive Moving- Average (ARMAV) models for identification of a time variant civil engineering structure subject to an earthquake. The two techniques are tested on measurements made during a pseudo dynamic test performed at the European Laboratory for StructuralAssessment (ELSA) on a full scale model of a four storey RC-building. Further, the estimated natural frequencies obtained with the two techniques are compared with natural frequencies calculated by using stiffness secant matrices estimated in a previous paper (Rytter et al.). The results obtained by the two ARMA V techniques correspond to results obtained using secant matrices