Abstract:Civil engineering structures are constructed for strength, serviceability and durability. The structures thus constructed involve huge investment and labour work. In order to protect the structure from various damages, periodic monitoring of structures is necessary. Hence Structural Health Monitoring (SHM) plays a vital role in diagnosing the state of the structure at every moment during its life period. For this purpose, sensors are deployed in the structures for its efficient health monitoring. Sensors canno… Show more
“…A random function compiled on the basis of arrays of measurement data of vibration parameters ϕ is considered stationary (in the broad sense), i.e., with the average of M ϕ(t) → const, while the covariance function depends solely on the difference between arguments τ − K ϕ (τ) Discrete Fourier transformation [16][17][18][19][28][29][30][31][32] may be used to process digital signals. Auto-covariance function of one data array or inter-covariance function of two arrays K ϕ (τ) is expressed as follows [78]:…”
Section: Covariance Model Of Vibration Signal Parametersmentioning
confidence: 99%
“…The purpose of the information received is to identify structural defects or to provide information on structural changes (usually using modal analysis). Artificial Neural Networks (ANNs), Pattern Search (PS) and Evolutionary Strategies (ES), such as the Genetic Algorithms (GA) [5], the Particle Swarm Optimization (PSO) [6], and the Covariance-Matrix Adaptation Evolution Strategy (CMA-ES) are some of the countless examples available in the literature [7,[16][17][18]. This article focuses on analysing hard-to-reach significant points (because the examined object is an old-structure bridge that is not adapted for dynamic research) by performing dynamic load tests (with a train moving at different speeds).…”
This article analyses the dispersion of vibration accelerations of a railway bridge during the passage of a train, and presents an analysis of their parameters after the application of the theory of covariance functions. The measurements of vibration accelerations at the fixed points of the beams of the overlay of the bridge were recorded in the time scale as digital arrays (matrices). The values of inter-covariance functions of the arrays of data of measurements of digital vibration accelerations and the values of auto-covariance functions of the individual arrays, changing the quantization interval in the time scale, were calculated. The compiled software Matlab 7 in the operator package environment was used in calculations. This article aims at determining the interdependencies of results of vibrations of bridge points rather than at the impact which a train makes on a bridge without emphasizing the modal parameters of the bridge. The aforementioned interdependencies make it possible to predict the results of hard-to-reach points.
“…A random function compiled on the basis of arrays of measurement data of vibration parameters ϕ is considered stationary (in the broad sense), i.e., with the average of M ϕ(t) → const, while the covariance function depends solely on the difference between arguments τ − K ϕ (τ) Discrete Fourier transformation [16][17][18][19][28][29][30][31][32] may be used to process digital signals. Auto-covariance function of one data array or inter-covariance function of two arrays K ϕ (τ) is expressed as follows [78]:…”
Section: Covariance Model Of Vibration Signal Parametersmentioning
confidence: 99%
“…The purpose of the information received is to identify structural defects or to provide information on structural changes (usually using modal analysis). Artificial Neural Networks (ANNs), Pattern Search (PS) and Evolutionary Strategies (ES), such as the Genetic Algorithms (GA) [5], the Particle Swarm Optimization (PSO) [6], and the Covariance-Matrix Adaptation Evolution Strategy (CMA-ES) are some of the countless examples available in the literature [7,[16][17][18]. This article focuses on analysing hard-to-reach significant points (because the examined object is an old-structure bridge that is not adapted for dynamic research) by performing dynamic load tests (with a train moving at different speeds).…”
This article analyses the dispersion of vibration accelerations of a railway bridge during the passage of a train, and presents an analysis of their parameters after the application of the theory of covariance functions. The measurements of vibration accelerations at the fixed points of the beams of the overlay of the bridge were recorded in the time scale as digital arrays (matrices). The values of inter-covariance functions of the arrays of data of measurements of digital vibration accelerations and the values of auto-covariance functions of the individual arrays, changing the quantization interval in the time scale, were calculated. The compiled software Matlab 7 in the operator package environment was used in calculations. This article aims at determining the interdependencies of results of vibrations of bridge points rather than at the impact which a train makes on a bridge without emphasizing the modal parameters of the bridge. The aforementioned interdependencies make it possible to predict the results of hard-to-reach points.
“…Recently some optimisation methods based on analogies with biology and physics have been introduced. Artificial Neural Networks (ANNs), Pattern Search (PS), and Evolutionary Strategies (ES), such as the Genetic Algorithms (GA) [5], the Particle Swarm Optimization (PSO) [6], and the Covariance-Matrix Adaptation Evolution Strategy (CMA-ES), are only some of the countless examples present in the literature [7].…”
Section: Optimisation Algorithms For Optimal Sensor Placementmentioning
Effective diagnostic and monitoring systems are highly needed in the building and infrastructure sector, to provide a comprehensive assessment of the structural health state and improve the maintenance and restoration planning. Vibration-based techniques, and especially ambient vibration testing, have proved to be particularly suitable for both periodic and continuous monitoring of existing structures. As a general requirement, permanent systems must include a sensing network able to run a continuous surveillance and provide reliable analyses based on different information sources. e variability in the environmental and operating conditions needs to be accounted for in designing such a sensor network, but it is mainly the structural typology that governs the optimal sensor placement strategy. Architectural heritage consists of a great variety of buildings and monuments that significantly differ from each other in terms of typology, historic period, construction techniques, and materials. In this paper, the main issues regarding seismic protection and analysis of the modern architectural heritage are introduced and applied to one of the vaulted structures built by Pier Luigi Nervi in the Turin Exhibition Centre. e importance of attaining an adequate level of knowledge in historic structures is also highlighted. After an overview of the Turin Exhibition Centre and its construction innovations, this paper focuses on Hall B, describing the structural design conceived by Pier Luigi Nervi. A seismic assessment of the structures of Hall B is then presented, considering the potential seismic damage to nonstructural elements. Subsequently, the application of an optimal sensor placement strategy is described with reference to two different scenarios: the first one corresponding to the undamaged structure and the second one that considers a possible damage to the infill walls. Finally, a novel damage-scenario-driven sensor placement strategy based on a combination of the two above mentioned is proposed and discussed. One of the major conclusions drawn from the analyses performed is that nonstructural elements undergoing seismic damage or degradation may significantly affect the global dynamic response and consequently the optimal sensing configurations.
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