References of "Dakhili, Khatereh 50041967"
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See detailA Gaussian damage function combined with sliced finite-element meshing for damage detection
Schommer, Sebastian; Dakhili, Khatereh UL; Nguyen, Viet Ha et al

in Journal of Civil Structural Health Monitoring (2022)

Bridges are among the most important components of transportation systems. Timely damage detection of these structures not only ensures reliability but also prevents catastrophic failures. This paper ... [more ▼]

Bridges are among the most important components of transportation systems. Timely damage detection of these structures not only ensures reliability but also prevents catastrophic failures. This paper addresses the damage assessment of bridges based on model updating techniques. Artificial damage was introduced to a beam that was a part of a real prestressed concrete bridge. The magnitude of the damage was increased stepwise, and static loading experiments were conducted in each step. A linear Finite-Element (FE) model with solid elements that were clustered into slices was utilised. A Gaussian bell-shaped curve was used as a damage function to describe the crack location using only three parameters. The experiments focused on sagging under dead load. Damage identification was performed in two steps using a coarse and a refined model. Initially, the FE model with a coarse mesh was updated to approximately localise the damage. Then, the FE model is refined in the vicinity of the approximately localised damage, and damage identification was accurately achieved. The results show that after the second step, the maximum error value of damage localisation is less than 0.5%. This approach could be later used to detect small damages that are not visible. [less ▲]

Detailed reference viewed: 20 (2 UL)
See detailEffects of various outdoor conditions on Structural Health Monitoring (SHM) of bridges using data from Luxembourg
Dakhili, Khatereh UL; Kebig, Tanja; Maas, Stefan UL

in VDI-Berichte 2379, 7. VDI-Fachtagung Baudynamik 27. und 28. April 2022, Würzburg (2022, April)

An increasing number of bridges are approaching the end of their service life due to corrosion and fatigue. Damages can be detected by performing regular measurements of characteristic values and ... [more ▼]

An increasing number of bridges are approaching the end of their service life due to corrosion and fatigue. Damages can be detected by performing regular measurements of characteristic values and comparing them with reference state data when there is no damage in the bridge. Unfortunately, environmental factors such as temperature variations have a considerable impact on the measurements and structural properties, such as stiffness. Since these environmental effects can be in the same order as damage, it is important to quantify them and reduce their effect before damage assessment. This paper aims to establish a correct reference model by investigating the parameters that affect structural responses. Doing so enables discrimination between structural property changes caused by damage and parameters such as temperature variations, load uncertainties, and various bearings. In this regard, several static and dynamic experiments are performed on a full scale undamaged prestressed concrete beam from a demolished bridge, and the results are reported. [less ▲]

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See detailBridge damage assessment based on static and dynamic flexibility matrices
Dakhili, Khatereh UL; Kebig, Tanja; Schäfer, Markus UL et al

in Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability (2022)

Being an indispensable part of transportation systems, Structural Health Monitoring (SHM) of bridges has been increasingly studied. Various SHM techniques not only enhance reliability and safety but also ... [more ▼]

Being an indispensable part of transportation systems, Structural Health Monitoring (SHM) of bridges has been increasingly studied. Various SHM techniques not only enhance reliability and safety but also reduce maintenance costs. Various bridge deteriorations change the structural properties, such as flexibility and stiffness. Therefore, damage assessment can be achieved by monitoring the structural matrices of bridges and tracking the deviations from the healthy-state or reference data. This paper focuses on damage detection of a prestressed concrete beam from a demolished bridge based on the flexibility matrix. The dynamic and static flexibility matrices are calculated numerically and experimentally when the beam is undamaged. The simulated and measured static flexibility matrices differ by only about 5 %. Additionally, the numerical dynamic flexibility matrix is strongly correlated with static results. The findings of this study can be employed as a basis for future damage detection applications when artificial damage is introduced. [less ▲]

Detailed reference viewed: 52 (7 UL)
See detailVerringerung des Temperatureinflusses bei der Überwachung von Brücken am Beispiel von Messdaten aus Luxemburg
Kebig, Tanja UL; Dakhili, Khatereh UL; Nguyen, Viet Ha UL et al

Conference given outside the academic context (2021)

A rising number of concrete bridges are showing increasing damage due to corrosion and fatigue. In addition to the regular standard visual inspection, the bridge’s condition can also be recorded using ... [more ▼]

A rising number of concrete bridges are showing increasing damage due to corrosion and fatigue. In addition to the regular standard visual inspection, the bridge’s condition can also be recorded using additional tests with repeated static loading and/or dynamic tests. To determine any damage to a structure and to check its structural stability, it is crucial to know the exact system properties of the bridge in its undamaged reference state. The system behavior is influenced by damage and bearing conditions and environmental influences, such as the structure’s temperature. The influence of temperature can even cause larger changes in the measured quantities (bending line or modal parameters) than real damage. Therefore, temperature effects should be compensated before any condition analysis. The present work aims to demonstrate the influence of different bearing types and temperature on a real bridge beam. For this purpose, various static and dynamic tests were performed in the undamaged reference state. [less ▲]

Detailed reference viewed: 127 (31 UL)