A note on predetermined earthquake damage scenarios for structural health monitoring

Abstract

SUMMARYIt is shown that the damage scenarios for site-specific building models, responding in highly nonlinear manner to strong earthquake ground-motion pulses, can be used in real-time health-monitoring systems. When it can be shown that such predictions produce robust results and are not sensitive to the details of the complete time history of strong ground motion, the predetermined earthquake damage scenarios (PEDS) method can produce reliable predictions of the location(s) and the degree(s) of structural damage in essentially real time. It is shown that for a full-scale building, damaged during the 1994 Northridge earthquake in California, PEDS based on onedimensional wave propagation in the layered building model would have produced accurate and realistic predictions of damage. In contrast to the vibrational health-monitoring methods that track changes in the frequency and stiffness of the characteristic functions, PEDS methods provide invaluable information for spatial and temporal identification of damage.

Nonparametric estimation of wave dispersion in high‐rise buildings by seismic interferometry

“…The linear seismic response of a building can be alternatively represented as superposition of its modes of vibration, characterized by their frequency, or as superposition of waves, characterized by their velocity of propagation . The latter approach has some advantages for prediction of response to impulsive loads as well as for SHM and has been gaining increasing interest . In both the forward and inverse analyses, with the exception of , it was assumed that the building deforms in shear only and that the wave propagation is predominantly one‐dimensional, vertically through the structure.…”

1D System identification of a 54‐story steel frame building by seismic interferometry

“…The wave methods for structural system identification and health monitoring are based on the view of the response as a wave propagation process and characterization of the structure by its velocities of wave propagation. The latter are directly related to the structural rigidity, for example, shear wave velocity , where μ is shear modulus, and ρ is mass density, and their decrease can be used as an indicator of the loss of stiffness, possibly caused by damage . The wave velocities, as well as their changes, can be inferred from the time lag τ between motions recorded at some distance h , as β = h / τ .…”

Detection thresholds in structural health monitoring

“…SDOF models with nonlinear properties can identify only the overall occurrence of some change in the model parameters, but the nature of the model is not suitable for detecting the location of that change. In contrast, even the simplest models that use wave propagation can identify accurately where the strain localizations have occurred, and they can be used to compare and verify the identified weak links with the observed damage in full-scale structures [36][37][38][39][40]. Fig.…”