B.K.Raghuprasad^{1}, N.Lakshmanan^{2}, N.Gopalakrishnan^{2}, K.Muthumani^{2}

*Structural Durability & Health Monitoring*, Vol.4, No.3, pp. 117-144, 2008, DOI:10.3970/sdhm.2008.004.117

Abstract The reduction in natural frequencies, however small, of a civil engineering structure, is the first and the easiest method of estimating its impending damage. As a first level screening for health-monitoring, information on the frequency reduction of a few fundamental modes can be used to estimate the positions and the magnitude of damage in a smeared fashion. The paper presents the Eigen value sensitivity equations, derived from first-order perturbation technique, for typical infra-structural systems like a simply supported bridge girder, modelled as a beam, an end-bearing pile, modelled as an axial rod and a simply… More >