Output-Only Parameters Identification of Earthquake-Excited Building Structures with Least Squares and Input Modification Process

Abstract

Damage detection and system identification with output-only information is an important but challenging task for ensuring the safety and functionality of civil structures during their service life. In this paper, a relatively simple and efficient iteration identification method consisting of the least squares estimation (LSE) technique and an input modification process is proposed for the simultaneous identification of structural parameters and the unknown ground motion. The spatial distribution characteristics of ground acceleration on earthquake-excited building structures are considered as additional information for parameters identification in each iterative step. First, the unknown input is estimated using the measured responses and the initial guesses of the structural parameters. The estimated input is then modified on the basis of the property of its spatial distribution. This modified input is further employed for providing the updated estimation of structural parameters. The iterative procedure would continue until the preset convergence criterion is satisfied. The accuracy of the proposed approach is numerically validated via a shear building model under the El Centro earthquake. The effects of signal noise, the number of sample points, and the initial guesses of structural parameters are discussed. The results show that the proposed approach can satisfactorily identify the structural parameters and unknown earthquakes.

Which Are the Effects of Hard and Soft Equality Constraints on the Iterative Outlier Elimination Procedure?

“…A of Equation (42). In that case, the false decisions are restricted to Type I error and Type II error.…”

“…where |∇ i | is the Minimal Detectable Bias (MDB 0 (i) ) for the case in which there is only one single alternative hypothesis, which can be computed for each individual alternative hypothesis according to Equation (42). For a single outlier, the variance of an estimated outlier, denoted by…”

“…The well-known least-squares (LS) has been widely used as a standard method of model parameters estimation in geodetic applications and many others branches of modern science [29][30][31][32][33][34][35][36][37][38][39][40][41][42]. This is due to the flexibility of the LS, since no concepts from probability theory are used in formulating the least-squares minimisation problem.…”

The Spatial Perspective in Post-Earthquake Evaluation to Improve Mitigation Strategies: Geostatistical Analysis of the Seismic Damage Applied to a Real Case Study

“…[1]. These variables tend to belong to different fields of knowledge, such as structural dynamics [2], earthquake engineering [3], geotechnics and geology [4], seismology [5], or even the urban configuration of cities [6]. On many occasions, this situation requires addressing clearly multidisciplinary problems, such as the forensic analysis of building damage levels resulting from the earthquake in the whole city, using approaches subjected to the limitations of each field of knowledge [7].…”

Structural Damage Detection and Health Monitoring

“…Examples include the flexural testing of high-performance steel beams, steel bar corrosion [26], testing of bonding behavior in reinforced concrete [27], among others [28,29]. At a higher level, using the current understanding of system mechanical behaviors, investigators have developed methods to identify, extract features, and classify the health of different structures using minimal knowledge of system behavior [30][31][32][33][34][35]. Supporting such work are other researchers that specialize in the long-term monitoring of damage and help strategize everything from sensor placement to understanding what the key parameters that need to be monitored are.…”