VULNERABILITY ASSESSMENT OF A CIVIC TOWER USING AMBIENT VIBRATION TESTS

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Gian Paolo Cimellaro ◽  
Marco Domaneschi ◽  
Ali Zamani Noori ◽  
Valentina Villa
Keyword(s):  
Vulnerability Assessment ◽  
Modal Identification ◽  
Ambient Vibration ◽  
Experimental Investigations ◽  
Collapse Mechanism ◽  
Fe Model ◽  
Dynamic Features ◽  
Ambient Vibration Tests ◽  
Vibration Tests ◽  
Output Only

This paper focuses on the vulnerability assessment of a civic tower built in 1512, which is now considered a national monument. It is the original bell tower of S. Ambrogio church that was destroyed in 1809. Experimental investigations have been carried out on this historical tower. First, detailed investigations have been carried out to identify the geometry of the tower as well as the mechanical features of the constituting materials. Then, ambient vibration tests have been applied using five Micro Electro-Mechanical Systems (MEMS) sensors to detect of the main dynamic features, e.g., modal parameters and damping. Two output-only identification methods, including Frequency Domain Decomposition and Random Decrement Techniques, have been used. The outcomes of the modal identification have been employed to inform the FE model. The numerical analysis can be used for vulnerability assessment, providing a valuable picture of possible damage evolution, tower collapse mechanism, and subsequently, useful hints for the execution of structural retrofitting strategies.

Experimental and Numerical Modal Identification of the Fossanova Gothic Cathedral

2007 ◽  
Vol 347 ◽  
pp. 351-358 ◽  
Author(s):  
Gianfranco de Matteis ◽  
I. Langone ◽  
Fabio Colanzi ◽  
Federico M. Mazzolani
Keyword(s):  
Seismic Vulnerability ◽  
Dynamic Behaviour ◽  
Shaking Table Test ◽  
Mediterranean Area ◽  
Modal Identification ◽  
Shaking Table ◽  
Ambient Vibration ◽  
Dynamic Features ◽  
Ambient Vibration Tests ◽  
Vibration Tests

This paper focuses on the dynamic behaviour of the Fossanova cathedral (Latina, ITALY), which represents a magnificent example of pre-Gothic style church, whose structural typology is largely present in the Mediterranean area, especially in many Countries characterised by a High-Medium seismic hazard. In particular, within the European research project PROHITECH, aiming at investigating the seismic vulnerability of such a structural typology, experimental and numerical analyses have been carried out. Firstly, detailed investigations have been devoted to the identification of the geometry of the main constructional parts as well as of the mechanical features of the constituting materials of the cathedral. Then, both Ambient Vibration Tests (AVT) and Numerical Modal Identification analyses by Finite Element Method (FEM) have been applied, allowing the detection of the main dynamic features. Finally, a refined FEM model reproducing the dynamic behaviour of the cathedral by using scaled physical quantities according to the Buckingham theorem has been developed. In fact, the present study has to be intended as a preliminary activity devoted to se up a shaking table test on a reduced scale physical model of Fossanova cathedral, which will be shortly carried out at the IZIIS laboratory (Skopje, Macedonia).

Structural Identification and Numerical Models for Slender Historical Structures

2015 ◽  
pp. 674-703 ◽  
Author(s):  
Dora Foti ◽  
Mariella Diaferio ◽  
Nicola Ivan Giannoccaro ◽  
Salvador Ivorra
Keyword(s):  
Model Updating ◽  
Numerical Models ◽  
Ambient Vibration ◽  
Mode Shapes ◽  
Fe Model ◽  
Detailed Structural Analysis ◽  
Ambient Vibration Tests ◽  
Great Confidence ◽  
Vibration Tests ◽  
The Time Domain

In the present chapter the theoretical basis of different methods developed for the calibration of FEMs are discussed. In general, Model Updating techniques are based on the use of appropriate functions that iteratively update selected physical properties (characteristics of the materials, stiffness of a link, etc.). In this way the correlation between the simulated response and the target value could improve if compared to an initial value. The FE model thus obtained can be used for a detailed structural analysis with a great confidence. The technique described in the first part of the chapter is applied to the evaluation of the structural properties of the tower of the Provincial Administration Building in Bari (Italy).The final purpose is to predict the performance of the tower to different combinations of static and dynamic loads, i.e. earthquakes or other induced vibrations. Ambient vibration tests have been performed on the above mentioned tower with the aim of determining its dynamic response and developing a procedure for modeling this building (Foti et al., 2012a). The Operation Modal Analysis (OMA) has been carried out both in the frequency domain and in the time domain to extract the dominant frequencies and mode shapes of the tower.

Blind Modal Identification of Non-Classically Damped Systems from Free or Ambient Vibration Records

2013 ◽  
Vol 29 (4) ◽  
pp. 1137-1157 ◽  
Author(s):  
Fariba Abazarsa ◽  
Fariborz Nateghi ◽  
S. Farid Ghahari ◽  
Ertugrul Taciroglu
Keyword(s):  
Degrees Of Freedom ◽  
Passive Control ◽  
Modal Identification ◽  
Ambient Vibration ◽  
Mode Shapes ◽  
Audio Signals ◽  
Civil Structures ◽  
Ambient Vibration Tests ◽  
Vibration Tests ◽  
Damped Systems

A significant segment of system identification literature on civil structures is devoted to response-only identification, simply because lack of measurements of input excitations for civil structures is a fairly common scenario. In recent years, several researchers have successfully adapted a second-order blind identification (SOBI) technique—a method originally developed for “blind source separation” of audio signals—to response-only identification of mechanical and civil structures. However, this development had been confined to fully instrumented classically damped systems. While several approaches have been proposed recently for extending SOBI to non-classically damped systems, they all require additional data such as velocity or analytic signals. Herein, we present a version of SOBI that requires only acceleration signals recorded during free or ambient vibration tests, and yields the system's complex mode shapes, natural frequencies, and damping ratios. Performance of the proposed technique is demonstrated through two synthetic examples: a ten-story structure possessing a passive control system, and a soil-structure system with seven degrees of freedom (seven-DOF).

scholarly journals Structural Identification and Numerical Models for Slender Historical Structures

2016 ◽  
pp. 196-222 ◽  
Author(s):  
Dora Foti ◽  
Mariella Diaferio ◽  
Nicola Ivan Giannoccaro ◽  
Salvador Ivorra
Keyword(s):  
Model Updating ◽  
Numerical Models ◽  
Ambient Vibration ◽  
Mode Shapes ◽  
Fe Model ◽  
Detailed Structural Analysis ◽  
Ambient Vibration Tests ◽  
Great Confidence ◽  
Vibration Tests ◽  
The Time Domain

In the present chapter the theoretical basis of different methods developed for the calibration of FEMs are discussed. In general, Model Updating techniques are based on the use of appropriate functions that iteratively update selected physical properties (characteristics of the materials, stiffness of a link, etc.). In this way the correlation between the simulated response and the target value could improve if compared to an initial value. The FE model thus obtained can be used for a detailed structural analysis with a great confidence. The technique described in the first part of the chapter is applied to the evaluation of the structural properties of the tower of the Provincial Administration Building in Bari (Italy).The final purpose is to predict the performance of the tower to different combinations of static and dynamic loads, i.e. earthquakes or other induced vibrations. Ambient vibration tests have been performed on the above mentioned tower with the aim of determining its dynamic response and developing a procedure for modeling this building (Foti et al., 2012a). The Operation Modal Analysis (OMA) has been carried out both in the frequency domain and in the time domain to extract the dominant frequencies and mode shapes of the tower.

scholarly journals Experimental evaluation of vibration based damage identification techniques on a pedestrian bridge

DYNA ◽  
2019 ◽  
Vol 86 (209) ◽  
pp. 9-16
Author(s):  
Angélica María Panesso Libreros ◽  
Johannio Marulanda ◽  
Peter Thomson
Keyword(s):  
Experimental Evaluation ◽  
Damage Identification ◽  
Ambient Vibration ◽  
Damage Localization ◽  
Damage State ◽  
Civil Structures ◽  
Ambient Vibration Tests ◽  
Vibration Tests ◽  
Output Only ◽  
Identification Techniques

Failures of civil structures, such as bridges, due to natural events or anthropic loads can generate significant social and economic impacts. As an alternative for the identification of damage in these structures, dynamic structural health monitoring has been proposed. This paper presents the experimental evaluation of three damage identification techniques on a full-scale footbridge. One of the evaluated techniques is based on damage localization vectors; a second technique is based on changes in the curvature of the modal shapes, while the third technique uses a numerical model and artificial neural networks for locating the damaged section. Five scenarios of controlled damage were induced in the footbridge. Output-only ambient vibration tests were performed at each damage state and the results of the identification techniques were analyzed. The three implemented techniques showed promising results for the numerical simulations, and two of these techniques produced satisfactory results in the experimental evaluation.

scholarly journals Modal identification of Karun IV arch dam based on ambient vibration tests and seismic responses

2016 ◽  
Vol 18 (6) ◽  
pp. 3869-3880
Author(s):  
R. Tarinejad ◽  
K. Falsafian ◽  
M. T. Aalami ◽  
M. T. Ahmadi
Keyword(s):  
Arch Dam ◽  
Modal Identification ◽  
Ambient Vibration ◽  
Seismic Responses ◽  
Ambient Vibration Tests ◽  
Vibration Tests

scholarly journals Dynamic Characterisation and Finite Element Updating of a RC Stadium Grandstand

Buildings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 141 ◽  
Author(s):  
Filipe Santos ◽  
Corneliu Cismaşiu ◽  
Ildi Cismaşiu ◽  
Chiara Bedon
Keyword(s):  
Finite Element ◽  
Model Updating ◽  
Three Dimensional ◽  
Modal Testing ◽  
Ambient Vibration ◽  
Fe Model ◽  
Modal Parameter ◽  
Ambient Vibration Tests ◽  
Fe Model Updating ◽  
Output Only

This paper reports on the dynamic characterisation of a Reinforced Concrete (RC) stadium grandstand module for the Sporting Stadium in Lisbon. To this aim, a three-dimensional (3D) Finite-Element (FE) numerical model, implemented according to the technical drawings of the structure, is first presented to provide preliminary estimates of the expected modal characteristics for the examined structural system. Ambient vibration tests are then carried out on the same grandstand, and used to extract the natural frequencies and vibration modes of the system, according to conventional state-of-the-art output-only modal parameter identification techniques. A sensitivity investigation and FE model updating study is hence presented for the grandstand, giving evidence of the major influencing parameters and key input data for the numerical fitting of the experimental modal testing results.

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