identificazione del danno

  • Special Issues

    • DAMAGE LOCALIZATION IN A HIGH-RISE BUILDING USING SEISMIC EXCITATION

    Maria Pina Limongelli, Luca Martinelli, Alessandra Zambrano

    The size of high-rise buildings and the significant expenses associated to using repeatedly ad hoc excitation sources make appealing the adoption of natural phenomena as sources of the excitation even if their randomness makes quite challenging the assessment of the accuracy of the damage identification algorithms implemented to check the structural health. in this paper the sensitivity of the interpolation damage detection method (IDDM) to the randomness of the base excitation is studied with reference to the case of an high-rise wall-frame building lately designed to be built in Salerno (Italy). a detailed numerical model of the building was used to simulate several damage scenarios and a recently proposed numerical procedure was applied to calculate a large set of realistic base inputs, corresponding to low intensity earthquakes complying with the Italian code for the location of the building. structural responses to the entire set of input calculated by the numerical model were used to check the reliability of the damage identification algorithms. results show that the interpolation damage detection method allows to take into account the effect of the variability of the input and provides a reliable detection of a damaged location both in the case of single and of multiple damage scenarios in case of medium to severe damages. The investigation on multiple damaged locations pointed out also a relationship between the severity of damage, the global damage pattern and the values of the damage index that can influence the reliability of the method in case of multiple light damages.

     

     

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  • Special Issues

    • NUMERICAL AND EXPERIMENTAL VALIDATION OF A STRUCTURAL HEALTH MONITORING TECHNIQUE FOR CRITICAL INFRASTRUCTURE

    Gianmario Benzoni, Noemi Bonessio, Giuseppe Lomiento

    Damage Identification method developed for infrastructure equipped with seismic response modification devices is hereafter summarized and validated through numerical and experimental case studies. The output-only method was tested via Finite Element analyses of two bridge structures, the Vincent Thomas Bridge and the Benicia Martinez Bridge, equipped with viscous dampers and friction pendulum bearings, respectively. The application of the method to real ambient vibration data from the Vincent Thomas Bridge proved successful in identifying early stages of degradation of seismic response modification devices. The Level III damage detection method was also applied to a three-span cable-stayed bridge, the Yokohama Bay Bridge, based on accelerometric records from the 2011 East Japan Earthquake. The integration of the method in an innovative monitoring systems aimed at the real-time remote assessment of the structural adequacy of aging critical infrastructure is under development.

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  • Uncategorized

    • FINITE ELEMENT ANALYSIS MODEL OF YING-XING TIMBER PAGODA BASED ON THE CONFORMATION CHARACTER AND DAMAGED CONDITION

    Jianli Yuan, Yingcai Fang, Ying Shi, Wei Chen, Jue Wang

    Ying-Xian timber pagoda is the existing oldest and highest wooden pagoda in China. Because of strong earthquake action and material aging, Ying-Xian timber pagoda is severely damaged and needs to be strengthened urgently. Aiming at the characteristics of complicated structural conformation and numerous damaged types of the pagoda, this paper discussed practical expression technology of computer simulation, determined the conformation character of layers-superposition and the modeling method of the pagoda based on the construction rule of traditional Chinese timber structures, and proposed the adjustment method to sectional area or elastic modulus of members according to the damage degree and position by the recognition research on damaged condition and stiffness variation of the pagoda. The finite element model of Ying-Xian timber pagoda was constructed and the dynamic behavior was analyzed by program ANSYS. The analysis results indicate that this FEA model is effective to describe the conformation character and damaged condition of the pagoda, and can be applied to seismic behavior study and security evaluation for the strengthening project of the pagoda.

  • Uncategorized

    • MULTI-SITE DAMAGE LOCALIZATION IN A SUSPENSION BRIDGE VIA AFTERSHOCK MONITORING

    Marco Domaneschi, Mariapina Limongelli, Luca Martinelli

    In earthquake affected areas the speed and reliability in assessing the damage suffered by strategic structures, such as long-span bridges, is of paramount importance both for civil protection operations and for organization and coordination of immediate remedial measures for the structure safety. In this paper we present the results obtained by applying a damage identification method termed Interpolation Damage Detection Method to a numerical model of the Shimotsui-Seto bridge, a suspension bridge with a long span steel truss deck (940 m). The method allows to detect localized reductions of stiffness along the bridge deck on the base of accelerometric responses recorded on the main girder during a damaging seismic event, or during an aftershock following the onset of damage. This is possible as long as responses recorded at the same locations on the undamaged structure are available. The response of the suspension bridge, subject to seismic excitation, has been calculated in the ANSYS framework using a finite element model derived from the original design data. In order to reproduce real life conditions, the numerical results in terms of temporal responses are artificially modified by including a background noise characteristic of classes of Micro Electro-Mechanical Systems type sensors. The reliability of the Interpolation Damage Detection Method has been numerically verified by simulating the damage through a reduction of stiffness in one or more elements of the deck. Several different locations of damage have been considered in order to study the influence on damage location the results provided by this Structural Health Monitoring methodology.