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Evaggelos Ntotsios Costas Papadimitriou Panagiotis Panetsos Grigorios Karaiskos Kyriakos Perros Philip C. Perdikaris 《Bulletin of Earthquake Engineering》2009,7(2):469-483
A bridge health monitoring system is presented based on vibration measurements collected from a network of acceleration sensors.
Sophisticated structural identification methods, combining information from the sensor network with the theoretical information
built into a finite element model for simulating bridge behavior, are incorporated into the system in order to monitor structural
condition, track structural changes and identify the location, type and extent of damage. This work starts with a brief overview
of the modal and model identification algorithms and software incorporated into the monitoring system and then presents details
on a Bayesian inference framework for the identification of the location and the severity of damage using measured modal characteristics.
The methodology for damage detection combines the information contained in a set of measurement modal data with the information
provided by a family of competitive, parameterized, finite element model classes simulating plausible damage scenarios in
the structure. The effectiveness of the damage detection algorithm is demonstrated and validated using simulated modal data
from an instrumented R/C bridge of the Egnatia Odos motorway, as well as using experimental vibration data from a laboratory
small-scaled bridge section. 相似文献
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Structural identification of Egnatia Odos bridges based on ambient and earthquake induced vibrations
Evaggelos Ntotsios Christos Karakostas Vasilios Lekidis Panagiotis Panetsos Ioannis Nikolaou Costas Papadimitriou Thomas Salonikos 《Bulletin of Earthquake Engineering》2009,7(2):485-501
The dynamic characteristics of two representative R/C bridges on Egnatia Odos motorway in Greece are estimated based on low
amplitude ambient and earthquake-induced vibrations. The present work outlines the instrumentation details, algorithms for
computing modal characteristics (modal frequencies, damping ratios and modeshapes), modal-based finite element model (FEM)
updating methods for estimating structural parameters, and numerical results for the modal and structural dynamic characteristics
of the two bridges based on ambient and earthquake induced vibrations. Transverse, bending and longitudinal modes are reliably
identified and stiffness-related properties of the piers, deck and elastomeric bearings of the FEMs of the two bridges are
estimated. Results provide qualitative and quantitative information on the dynamic behavior of the bridge systems and their
components under low-amplitude vibrations. Modeling assumptions are discussed based on the differences in the characteristics
identified from ambient and earthquake vibration measurements. The sources of the differences observed between the identified
modal and structural characteristics of the bridges and those predicted by FEMs used for design are investigated and properly
justified. 相似文献
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Maria Tombrou Aggeliki Dandou Costas Helmis Evaggelos Akylas George Angelopoulos Helena Flocas Vasiliki Assimakopoulos Nikolaos Soulakellis 《Boundary-Layer Meteorology》2007,124(1):61-79
In the present study, an attempt is made to assess the atmospheric boundary-layer (ABL) depth over an urban area, as derived
from different ABL schemes employed by the mesoscale model MM5. Furthermore, the relationship of the mixing height, as depicted
by the measurements, to the calculated ABL depth or other features of the ABL structure, is also examined. In particular,
the diurnal evolution of ABL depth is examined over the greater Athens area, employing four different ABL schemes plus a modified
version, whereby urban features are considered. Measurements for two selected days, when convective conditions prevailed and
a strong sea-breeze cell developed, were used for comparison. It was found that the calculated eddy viscosity profile seems
to better indicate the mixing height in both cases, where either a deep convective boundary layer develops, or a more confined
internal boundary layer is formed. For the urban scheme, the incorporation of both anthropogenic and storage heat release
provides promising results for urban applications. 相似文献
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