System identification and modeling of a dynamically tested and gradually damaged 10‐story reinforced concrete building

Abstract

SummaryThis paper discusses the dynamic tests, system identification, and modeling of a 10-story reinforced concrete building. Six infill walls were demolished in 3 stages during the tests to introduce damage. In each damage stage, dynamic tests were conducted by using an eccentric-mass shaker. Accelerometers were installed to record the torsional and translational responses of the building to the induced excitation, as well as its ambient vibration. The modal properties in all damage states are identified using 2 operational modal analysis methods that can capture the effect of the wall demolition. The modal identification is facilitated by a finite element model of the building. In turn, the model is validated through the comparison of the numerically and experimentally obtained modal parameters. The validated model is used in a parametric study to estimate the influence of structural and nonstructural elements on the dynamic properties of the building and to assess the validity of commonly used empirical formulas found in building codes. Issues related to the applicability and feasibility of system identification on complex structures, as well as considerations for the development of accurate, yet efficient, finite element models are also discussed.

Nonlinear dynamic tests of a reinforced concrete frame building at different damage levels

“…A similar frequency drop was also observed in the dynamic response of another structure. 13 However, the drop is more significant in the case of this building due to its deterioration.…”

“…Actual buildings have been instrumented to obtain their response to seismic excitations as part of the California Strong Motion Instrumentation Program (CSMIP) program, 10 and in rare cases tested. [11][12][13] However, in most cases, the excitations were not strong enough to push the structures into the nonlinear response range. Even in the few cases the buildings behaved nonlinearly, the data were obtained from a single state of damage.…”

Evolution of modal characteristics of a mid‐rise cold‐formed steel building during construction and earthquake testing

“…Vibration-based structural identification studies have initially focused on using data simulated by numerical models (e.g., other studies [6][7][8][9] ) or recorded from small-scale experiments of structural systems and assemblies (e.g., other studies [9][10][11] ). More recently, a large amount of research has been extended to use recorded data obtained from real structures (e.g., buildings and bridges) to monitor their dynamic characteristics under operational conditions (e.g., other studies [12][13][14][15][16] ) or during construction and demolition (e.g., other studies [17,18] ). However, the monitoring data of real structures do not often involve structural damage induced by extreme loading events (e.g., earthquakes and fire).…”

Sparse Sum-of-Squares Optimization for Model Updating Through Minimization of Modal Dynamic Residuals

“…Although these approaches are straightforward and easy to implement, only using the resonance frequency data could not ensure successful model updating (Salawu 1997). Alternatively, other modal properties, such as mode shapes and modal flexibility, are included in the optimization objective function to utilize more information and thus provide better updating results (Jaishi and Ren 2006;Koh and Shankar 2003;Moaveni et al 2013;Nozari et al 2017;Sanayei et al 2001;Yousefianmoghadam et al 2018;Zhang and Johnson 2013). To this end, the modal dynamic residual approach accomplishes FE model updating by forming an optimization problem that minimizes the residuals of the generalized eigenvalue equations in structural dynamics (Farhat and Hemez 1993;Kosmatka and Ricles 1999;Zhu et al 2016).…”