Monitoring the Modal Properties of an RC School Building during the 2016 Central Italy Seismic Swarm

Gara, Fabrizio; Arezzo, Davide; Nicoletti, Vanni; Carbonari, Sandro

doi:10.1061/(asce)st.1943-541x.0003025

Cited by 20 publications

(6 citation statements)

References 27 publications

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“…A very low structural damping, calibrated through Rayleigh formulation as 𝜁𝜁 = 0.005 at the 1.30Hz and 5.45 Hz, equal to 𝛼𝛼 = 0.06595 for the mass-proportional coefficient and 𝛽𝛽 = 2.35785e − 04 for the stiffness-proportional coefficient is used. Small values of damping are consistent with the low amplitude of the seismic input(Gara et al, 2021), as further confirmed by the damping analysis performed on the recordings. Comparisons between the recordings and the simulated time-histories in acceleration and the related Fourier transforms are shown for each sensor in Figures11-14.…”

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confidence: 76%

“…The epicentre of the first event (denominated Event 1) is 35 km far from the Bell Tower at a latitude of 38.1332 and longitude of 15.1643, with depth of the hypocentre of 10 km; the second event (indicated as Event 2) is located at latitude 38.1328 and longitude 15.9537, 35 km away from the Bell Tower and hypocentre depth of 14 km.The time-histories recorded at the foundation (Sensor 1) are used as seismic inputs applied at the same location in the finite element model including the soil underneath as prescribed accelerations, rather than applied to the bedrock after a pertinent back propagation. It is worth emphasising that the signals on the 3 principal directions, recorded at the base do not correspond to the free-field seismic motion at the building location, owing to kinematic and inertial soil-structure interaction effects(Gara et al 2021), hence, they cannot be applied at the soil bedrock as conventional done in soil-structure interaction analyses. Therefore, the input acceleration time-histories about the 3 principal directions, 𝑢𝑢̈𝑥𝑥, 𝑢𝑢̈𝑦𝑦, and 𝑢𝑢̈𝑧𝑧, are exactly those from the recordings at foundation level, depicted in Figure11.…”

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Seismic response of nonlinear soil-structure interaction systems through the Preisach formalism: the Messina Bell Tower case study

Cacciola

Caliò

Fiorini

et al. 2021

Bull Earthquake Eng

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In this paper the seismic response of linear behaving structures resting on compliant soil is addressed through the application of the Preisach formalism to capture the soil nonlinearities. The novel application of the Preisach model of hysteresis for nonlinear soil-structure interaction problems is explored through the study of the seismic response of a real structure. Through a harmonic balance procedure, furthermore, simplified nonlinear springs and dashpots are derived in closed form for a ready and accurate evaluation of the nonlinear soil-structure interaction response. The selected case study is the bell tower of the Messina Cathedral in Italy. The Bell Tower hosts the largest and most complex mechanical and astronomical clock in the world and it has been recently equipped by a permanent seismic monitoring system. A pertinent finite element (FE) model including the superstructure and the soil underneath, has been defined using authentic drawings and engineering design reports. The modal properties of the FE model have been compared with the experimental ones, identified from environmental noise recorded through the seismic monitoring system.Furthermore, the FE model has been validated by means of acceleration time histories recorded at different floors during two independent seismic events. A nonlinear incremental dynamic analysis of the Bell Tower has been also performed. The seismic response obtained by the complete FE analysis, has been compared with the proposed Preisach lumped parameter model, assembled with nonlinear 2 springs and nonlinear dashpots. The results are well in agreement, offering an alternative promising strategy for the nonlinear soil-structure interaction studies.

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confidence: 76%

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confidence: 99%

Seismic response of nonlinear soil-structure interaction systems through the Preisach formalism: the Messina Bell Tower case study

Cacciola

Caliò

Fiorini

et al. 2021

Bull Earthquake Eng

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“…The accuracy of the identified model in reproducing the building response is evaluated comparing the predicted and measured time histories of accelerations through the comparison metrics proposed by Kavrakov et al [20], which consider several signal properties such as phase, peak, root mean square, and frequency contents. A detailed explanation of the approach can be found in Gara et al (2021) [21].…”

Section: Description Of the Linearization Proceduresmentioning

confidence: 99%

The Tracking of Modal Parameters for a Reinforced Concrete Building During Low-Medium Intensity Earthquakes

Arezzo¹,

Nicoletti²,

Carbonari³

et al. 2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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This paper presents the results of the dynamic monitoring carried out on a school building in central Italy during the seismic sequence following the first main shock of the 2016 Central Italy earthquake. The building is located in the historical centre of Camerino and consists of a reinforced concrete frame structure with masonry infill walls. The school, dating back to the 60s, underwent seismic retrofit in 2013 through the construction of 2 dissipative towers, a recent patented system for seismic protection of buildings. In August 2016 a dynamic monitoring system was installed on the building, positioning an array of accelerometers both on the top two floors of the structure and on the foundation level; this made it possible to record the building response to the aftershocks that occurred during the monitoring period, and the corresponding seismic input. The dynamic characteristics of the structure during the monitoring period are identified starting from the response of the structure subjected to the seismic swarm following the main event, and to the environmental vibrations between two subsequent events. Although during the monitoring days the building did not suffer any damage, the response of the structure proved to be nonlinear and strongly dependent on the amplitude of the accelerations to which it was subjected; in this work, a procedure to linearize the structural response and carry out the dynamic identification in terms of modal parameters starting from the nonstationary response of the structure is proposed.

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“…However, although this strategy is widely recognised to be of useful application, a relatively low number of works can be found dealing with applications on real or scaled structures. Some authors performed vibration-based tests on real buildings during the gradual artificially induced damage to both structural and non-structural components [5][6][7] or due to earthquakes, [8,9] while others investigated the modal property evolutions of laboratory specimens representative of Reinforced Concrete (RC), [10][11][12][13][14] steel, [15,16] and steel-concrete composite structures [4,17] subjected to displacements and forces such as to produce structural and non-structural damage. However, a lack of works dealing with damage evaluation of infilled structures by using vibration-based techniques can be observed in the literature.…”

Section: Introductionmentioning

confidence: 99%

Detection of infill wall damage due to earthquakes from vibration data

Nicoletti

Arezzo

Carbonari

et al. 2022

Earthq Engng Struct Dyn

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Vibration‐based methodologies are nowadays gaining increasing application for the structural health monitoring and damage detection on buildings, especially damage due to earthquakes. A fast and efficient damage recognition on structural and non‐structural components can support the decision‐making process after exceptional events and may contribute to reduce troubles due to the inoccupancy of buildings. The paper offers insights on the usefulness of vibration data for the damage detection in infilled frame structures starting from the tracking of the stiffness and modal properties of an infilled laboratory steel‐concrete composite mock‐up subjected to vibration‐based tests. The mock‐up has been object of an extensive experimental campaign that involved both quasi‐static cyclic and dynamic tests characterized by different level of excitation provided to the structure. Cyclic load tests are performed to simulate the effects of earthquakes by progressively increasing the imposed displacement to the cracking and then to the failure of infills. The dynamic tests are executed at the various steps to capture the effects of the infill damage on the global dynamic response triggered by excitations of different amplitudes. Results of dynamic and quasi‐static tests are used to correlate the infill damage with the mechanical properties and the modal parameters of the mock‐up, as well as with the vibration amplitude, providing information about the damage expected during low and moderate seismic events as a function of the registered dynamic response of the building by structural health monitoring systems.

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Monitoring the Modal Properties of an RC School Building during the 2016 Central Italy Seismic Swarm

Cited by 20 publications

References 27 publications

Seismic response of nonlinear soil-structure interaction systems through the Preisach formalism: the Messina Bell Tower case study

Seismic response of nonlinear soil-structure interaction systems through the Preisach formalism: the Messina Bell Tower case study

The Tracking of Modal Parameters for a Reinforced Concrete Building During Low-Medium Intensity Earthquakes

Detection of infill wall damage due to earthquakes from vibration data

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