Detection of Building Damage Using Helmholtz Tomography

Abstract

High-rise buildings with dense permanent installations of continuously recording accelerometers offer a unique opportunity to observe temporal and spatial variations in the propagation properties of seismic waves. When precise, floor-by-floor measurements of frequency-dependent travel times can be made, accurate models of material properties (e.g., stiffness or rigidity) can be determined using seismic tomographic imaging techniques. By measuring changes in the material properties, damage to the structure can be detected and localized after shaking events such as earthquakes. Here, seismic Helmholtz tomography is applied to simulated waveform data from a high-rise building, and its feasibility is demonstrated. A 52-story dual system building-braced-frame core surrounded by an outrigger steel moment frame-in downtown Los Angeles is used for the computational basis. It is part of the Community Seismic Network and has a three-component accelerometer installed on every floor. A finite-element model of the building based on structural drawings is used for the computation of synthetic seismograms for 60 damage scenarios in which the stiffness of the building is perturbed in different locations across both adjacent and distributed floors and to varying degrees. The dynamic analysis loading function is a Gaussian pulse applied to the lowest level fixed boundary condition, producing a broadband response on all floors. After narrowband filtering the synthetic seismograms and measuring the maximum amplitude, the frequency-dependent travel times and differential travel times are computed. The travel-time and amplitude measurements are converted to shear-wave velocity at each floor via the Helmholtz wave equation whose solutions can be used to track perturbations to wavefronts through densely sampled wavefields. These results provide validation of the method's application to recorded data from real buildings to detect and locate structural damage using earthquake, explosion, or ambient seismic noise data in near-real time. Electronic Supplement: Table and figures describing nine additional velocity imaging tests that were run using the same procedure described in the main article.

Structural change detection applying long-term seismic interferometry by deconvolution method to a modern civil engineering structure (New Zealand)

“…As other researchers suggested (e.g. Kohler et al 2018), detection of the velocity-based variation might indicate the location of the potential damage. In this study, changes of the time delay are located at sensors 4 and 5 and only sensor 5 in transverse and longitudinal direction, respectively, corresponding to a change of the floor design, i.e.…”

“…SIbyD had since been applied to earthquake data (e.g. Kohler et al 2007Kohler et al , 2018Todorovska and Trifunac 2008;Newton and Snieder 2012;Wen and Kalkan 2017;Michel and Guéguen 2018;Guéguen et al 2019) and ambient vibrations (e.g. Prieto et al 2010;Nakata and Snieder 2014;Mordret et al 2017).…”

A trajectory mechanics approach for the study of wave propagation in an anisotropic elastic medium

“…The technique was recently applied to construct frequency-dependent rays for several numerical examples (Protasov and Gadylshin 2017). A data analysis and imaging procedure known as Helmholtz tomography, based upon similar ideas, was applied to surface wave observations by Lin and Ritzwoller (2011) and used for the study of building vibrations by Kohler et al (2018). Our work, and that presented in Vasco and Nihei (2019), can be considered as an extension of the work of Foreman (1989, as well as a generalization of related efforts in quantum mechanics and physics (Orefice et al 2009), to the full vector elastodynamic equations of motion.…”