Impulse response analysis of the Van Nuys 7-storey hotel during 11 earthquakes and earthquake damage detection

Abstract

Wave travel times of vertically propagating waves are measured in the Van Nuys 7‐storey hotel, located in the Los Angeles metropolitan area, from impulse response functions computed by deconvolution of the recorded earthquake response. East‐West response data from 11 earthquakes over a period of 24 years are analysed. Changes in wave travel times are used to infer about local (between sensors) and global changes of structural stiffness, from one event to another, and with time during the earthquakes that damaged the building (San Fernando and Northridge). Also, wave travel times are used to estimate the fundamental fixed‐base frequency of the building, f1, which is compared with independent estimates of the soil–structure system frequency fsys during the same earthquakes and during five ambient vibration tests. The analysis shows that monitoring only the changes of fsys can be misleading for structural health monitoring and can lead to erroneous alarms, while monitoring changes of f1 over suitably chosen time windows (before, during, and after excitation by strong earthquake motions) can be a powerful and robust tool for structural health monitoring. It is concluded that, under favourable conditions, this method can be used as a tool for global and local structural health monitoring. Copyright © 2007 John Wiley & Sons, Ltd.

Rotations in a shear-beam model of a seven-story building caused by nonlinear waves during earthquake excitation

“…Gicˇev and Trifunac [18,19] used the energy and power of nonlinear waves to identify the location of damage. The first applications of the impulse-response functions computed by deconvolution [20] for detecting local changes in stiffness, and for earthquake damage detection in general, appeared in the studies of the seven-story Van Nuys Hotel [21,22] and the Imperial County Services Building [23][24][25].…”

Parametric Estimation of Wave Dispersion for System Identification of Building Structures

“…The posterior estimates obtained from equation (15) should be corrected to satisfy the constraints shown in equation (8). For this purpose, the posterior Gaussian pdf that is resulted from equation (15) is truncated at the constraint edges.…”

“…The velocity of shear waves, which are induced by seismic base excitation and propagating along the building height, can be estimated from the impulse response functions (IRFs) of the building structure, e.g., [1][2][3][4][5][6] to name only a few. Considering that the shear wave velocity is related to the lateral stiffness of the building structure, several studies have been able to detect structural damage in terms of loss of effective lateral stiffness by comparing estimated shear wave velocities from the pre-and post-damage IRFs (e.g., [7][8][9]). …”

Fundamental period elongation of a RC building during the Pollino seismic swarm sequence

“…This approach is more important when considering the increasing number of aging structures and infrastructures, especially exposed to seismic prone activity for seismic risk. In the last two decades several innovative techniques have been proposed to identify the dynamic characteristics of real engineering structures [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Fast monitoring procedures are gaining ground; they obtain useful information about the extent of damage in a large number of strategic buildings during and after seismic events by using the records from a limited number of sensors located in the structure.…”