Environmental effects on natural frequencies of the San Pietro bell tower in Perugia, Italy, and their removal for structural performance assessment

Ubertini, Filippo; Comanducci, Gabriele; Cavalagli, Nicola; Pisello, Anna Laura; Materazzi, Annibale Luigi; Cotana, Franco

doi:10.1016/j.ymssp.2016.05.025

Cited by 167 publications

(109 citation statements)

References 34 publications

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“…The recent improvement and diffusion of effective automated operational modal analysis (OMA) techniques [8][9][10][11][12][13] have further contributed to elect frequencies as privileged damage detection parameter. On the other hand, natural frequencies are often not especially sensitive to local damage, while they are strongly affected by environmental and operational conditions, such as temperature, humidity [5,14], and, particularly in the case of tall structures, wind intensity [15].…”

Section: Introductionmentioning

confidence: 99%

Effect of Environmental Conditions on the Modal Response of a 10‐Story Reinforced Concrete Tower

Regni

Arezzo

Carbonari

et al. 2018

Shock and Vibration

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We analyse the effect of temperature and wind velocity on the natural frequencies and modal damping ratios of the Faculty of Engineering Tower at the Università Politecnica delle Marche, a 10-story reinforced concrete frame building, permanently monitored with low-noise accelerometers. The data recorded over the first 5 months of monitoring demonstrate that temperature variations and wind intensity have a clear effect on the first three natural frequencies and the corresponding damping ratios. Temperature is positively correlated to the first and second frequencies, corresponding to shear displacement modes and negatively correlated to the third frequency, corresponding to a torsional mode. All frequencies are positively correlated to wind velocity and changes in damping ratios are inversely correlated to any change in frequency. A mechanical explanation of these phenomena is offered, based on a critical review of literature case studies. These results suggest that using changes in modal parameters for damage detection always requires accurate knowledge of the correlation between modal parameters and environmental quantities (temperature, humidity, and wind velocity), an information which is only available through long-term continuous monitoring of the structural response.

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Section: Introductionmentioning

confidence: 99%

Effect of Environmental Conditions on the Modal Response of a 10‐Story Reinforced Concrete Tower

Regni

Arezzo

Carbonari

et al. 2018

Shock and Vibration

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“…The effect of environmental conditions has been investigated [49] and various methods are adopted to remove this effect, such as principal component analysis (PCA) [50,51], factor analysis [52], nonlinear PCA based on unsupervised support vector machine [53], the Cointegration concept for non-stationary time series [54], PCA method in time-varying systems [55], etc. Moreover, the novelty detection and outlier analysis are used to perform the lowest level of damage identification in operational conditions [56,57], and the multivariate statistical analysis method becomes popular for automatically revealing the damage existence using vibration data under changing environmental and operational conditions [58][59][60].…”

Section: Methods For Changing Environmental Conditionsmentioning

confidence: 99%

The State-of-the-Art on Framework of Vibration-Based Structural Damage Identification for Decision Making

2017

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Abstract:Research on detecting structural damage at the earliest possible stage has been an interesting topic for decades. Among them, the vibration-based damage detection method as a global technique is especially pervasive. The present study reviewed the state-of-the-art on the framework of vibration-based damage identification in different levels including the prediction of the remaining useful life of structures and the decision making for proper actions. This framework consists of several major parts including the detection of damage occurrence using response-based methods, building reasonable structural models, selecting damage parameters and constructing objective functions with sensitivity analysis, adopting optimization techniques to solve the problem, predicting the remaining useful life of structures, and making decisions for the next actions. For each part, the commonly used methods were reviewed and the merits and drawbacks were summarized to give recommendations. This framework is aimed to guide the researchers and engineers to implement step by step the structure damage identification using vibration measurements. Finally, the future research work in this field is recommended.

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“…Saisi et al [21,22] present the results of continuous dynamic monitoring for Gabbia Tower in Italy during a period of 8 months. Identified natural frequencies are observed to vary by 5-11% when the measured temperatures range from 2 ∘ C to 45 ∘ C. Ubertini et al [23] monitor the modal frequencies of San Pietro Bell Tower during more than nine-month period. Temperature variation produces significant changes in natural frequencies, up to 16 MHz/ ∘ C, while effects of air humidity were relatively marginal.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Temperature Effect on Modal Frequency of Concrete Beam Based on Field Monitoring Data

Shan

Wang

Jiao

2018

Shock and Vibration

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Temperature variation has been widely demonstrated to produce significant effect on modal frequencies that even exceed the effect of actual damage. In order to eliminate the temperature effect on modal frequency, an effective method is to construct quantitative models which accurately predict the modal frequency corresponding to temperature variation. In this paper, principal component analysis (PCA) is conducted on the temperatures taken from all embedded thermocouples for extracting input parameters of regression models. Three regression-based numerical models using multiple linear regression (MLR), back-propagation neural network (BPNN), and support vector regression (SVR) techniques are constructed to capture the relationships between modal frequencies and temperature distributions from measurements of a concrete beam during a period of forty days of monitoring. A comparison with respect to the performance of various optimally configured regression models has been performed on measurement data. Results indicate that the SVR exhibits a better reproduction and prediction capability than BPNN and MLR models for predicting the modal frequencies with respect to nonuniformly distributed temperatures. It is succeeded that temperature effects on modal frequencies can be effectively eliminated based on the optimally formulated SVR model.

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Environmental effects on natural frequencies of the San Pietro bell tower in Perugia, Italy, and their removal for structural performance assessment

Cited by 167 publications

References 34 publications

Effect of Environmental Conditions on the Modal Response of a 10‐Story Reinforced Concrete Tower

Effect of Environmental Conditions on the Modal Response of a 10‐Story Reinforced Concrete Tower

The State-of-the-Art on Framework of Vibration-Based Structural Damage Identification for Decision Making

Modeling of Temperature Effect on Modal Frequency of Concrete Beam Based on Field Monitoring Data

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