Aspects of Vibration-Based Methods for the Prestressing Estimate in Concrete Beams with Internal Bonded or Unbonded Tendons

Aloisio, Angelo

doi:10.3390/infrastructures6060083

Cited by 7 publications

(4 citation statements)

References 51 publications

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“…Based on the outcome of several studies, they analyzed the application of vibration-based methods for the detection of prestress losses, concluding that, in the case of uncracked beams, changes in prestress forces do not affect natural frequencies. Nowadays, research on dynamic monitoring of prestressed concrete structures remains active [22][23][24][25]. The goal of these projects is usually to verify and validate the effectiveness of vibration-based methods for damage detection.…”

Section: Introductionmentioning

confidence: 99%

On the Effectiveness of Vibration-Based Monitoring for Integrity Management of Prestressed Structures

et al. 2021

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In this paper, the effectiveness of vibration-based tests for the detection of damages for prestressed concrete beams is investigated. Despite large research efforts, discrepant and sometimes contradicting conclusions have been drawn regarding the efficacy and reliability of vibration-based monitoring for prestressed structures. Herein, a contribution to this discussion is provided by tackling the problem from a different perspective. Specifically, the question that this paper intends to answer is: “Do vibration-based tests support decision-makers in integrity management operations for prestressed elements?” The discussion is carried out by comparing the performance of prestressed and ordinary reinforced concrete beams with similar capacities. Both analytical and numerical case studies are considered. Results show that, for prestressed beams, in contrast to reinforced concrete beams, modal parameters can provide information regarding damage only when the structure is close to its ultimate conditions. This makes this information hardly useful for integrity management purposes and the effectiveness of vibration-based tests questionable for this type of structural element.

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Section: Introductionmentioning

confidence: 99%

On the Effectiveness of Vibration-Based Monitoring for Integrity Management of Prestressed Structures

et al. 2021

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“…Regardless of the sensitivity issues of the vibration test, it is evident from the obtained results that the (pre-)stresses applied by pressing the salvaged timber elements into the voids affected the first eigenfrequency and damping ratio of the large-scale DLT elements. Whether or not the natural frequency is affected by prestressing has been discussed in some previous studies on other forms of beams made with other types of materials [34,35]. For the interpretation of the results in the study presented here, however, it should be noted that the (pre-)stresses applied here are quite different from the conventional ones.…”

Section: Vibration Characteristicsmentioning

confidence: 67%

Bending Properties and Vibration Characteristics of Dowel-Laminated Timber Panels Made with Short Salvaged Timber Elements

2023

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Salvaged timber elements often have length limitations, and therefore, their reuse in structural products normally would require additional processing and end-to-end joining. This increases the costs of reusing such materials, which makes them even less attractive to the timber sector. In the presented research, a new approach is proposed for reusing short, salvaged timber elements combined with new (full-scale) timber boards to fabricate dowel-laminated timber (DLT) panels without significant processing or end-to-end joining or gluing. In this approach, salvaged timber elements are pressed in the system in such a way that they can contribute to the bending performance of the DLT panels by resisting compression stress. In order to evaluate the effectiveness, several small-scale and large-scale DLT panels were fabricated. Salvaged plywood tenons were used as connectors. The bending stiffness of the small-scale DLT panels and the first eigenfrequency, damping ratio, bending properties, and failure modes of the large-scale DLT panels were evaluated. The results exhibited that by using the proposed approach, the short, salvaged timber elements can contribute substantially to the bending stiffness of the DLT panels without requiring end-to-end joining or gluing. On average, about a 40% increase in the bending stiffness could be achieved by pressing in the salvaged timber elements, which results in relatively similar stiffness properties compared to conventional DLT panels. One further characteristic is that the failure of the panels, and therefore the panel’s strength, is mainly governed by the quality of the full-scale timber boards instead of the salvaged ones. This can be beneficial for practical use as the qualitative assessment of the strength properties of salvaged timber becomes less critical.

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“…This is consistent with Hamed and Frostig (2006), which concluded that the prestressing force has no significant influence on the natural frequency of prestressed concrete under nonlinear conditions. Aloisio (2021) examined the structural rigidity under the influence of prestressing force and discovered that the Young's modulus of all prestressed concrete samples showed a nearly constant elasticity at all increasing loads, thereby indicating that the rigidity was not affected by prestressing force. Furthermore, Atmaca (2019) compared the numerical natural periods of reinforced and prestressed concrete girders with identical dimensions and properties under linear and nonlinear conditions and observed that the vibrational modes of the two structures are identical.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Properties Comparison of 1D, 2D, and 3D Model for Concrete Box-Girder Bridge of 40-meter Span

Ibrahim

Aminullah

Awaludin

et al. 2022

jcef

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Concrete box-girder structure is considered the thin-walled structure, undergoing deformation and forces, as well as having structural rigidity in three dimensional directions. However, it’s commonly modeled as 1D structure for the sake of design practicality, which influences the numerical result of its dynamic properties when compared to both real time SHMS and field test result. To see how far the difference of the dynamic properties between 1D, 2D, and 3D model of concrete box-girder structure, the concrete box-girder structure is modeled as 1D (frame), 2D (shell), and 3D (solid) element with MIDAS Civil 2019. Considering the allowable deflection and stress limited by design code, concrete box-girder structure is modeled and analyzed as linearly elastic material. The dynamic properties obtained from these 3 models were compared with those obtained from real time SHMS and field test. These results indicate that both natural frequency and period of 2D and 3D models are close to those of real time SHMS and field test. However, the natural frequency of 1D model is slightly larger than the real SHMS and field test, indicating that 1D model gives the slightly overestimate natural frequency and structural rigidity compared to the reality. Unlike 2D and 3D model, the structure is accounted to have the uniform sectional rigidity along transversal direction in 1D model. This is why 1D model seems to have higher structural rigidity compared to 2D and 3D model, which subsequently yields the higher natural frequency than 2D and 3D model. This research proves that the designers’ discretion is advised if 1D model is used for the sake of design practicality.

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Aspects of Vibration-Based Methods for the Prestressing Estimate in Concrete Beams with Internal Bonded or Unbonded Tendons

Cited by 7 publications

References 51 publications

On the Effectiveness of Vibration-Based Monitoring for Integrity Management of Prestressed Structures

On the Effectiveness of Vibration-Based Monitoring for Integrity Management of Prestressed Structures

Bending Properties and Vibration Characteristics of Dowel-Laminated Timber Panels Made with Short Salvaged Timber Elements

Dynamic Properties Comparison of 1D, 2D, and 3D Model for Concrete Box-Girder Bridge of 40-meter Span

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