Abstracts Archive

Damage to bridges is related to road safety and traffic disruption, therefore to substantial direct and indirect economic losses. Hence, there is an urgent need for development and application of systems that can assess the structural condition of bridges. In this study, a methodology for damage ide...

The evaluation of the actual state of structural systems based on available response measurements is a relevant aspect in civil engineering. To this end, Bayesian model updating provides a sound theoretical framework that allows to include the unavoidable uncertainties arising in modeling and monito...

A direct scheme is presented for output feedback assignment and uncertainty quantification of perturbation-invariant eigenvalues in controllable and observable systems. The feedback is realized through offline signal processing of open-loop input-output data, and the eigenvalue invariance is imposed...

In updated model based structural health monitoring problems, updating of displacement-strain transformation matrix has not garnered much attention over the years, as most studies focus on updating mass and stiffness matrices. In this study, updating of the parametrized displacement-strain transform...

Time-dependent phenomena, such as creep of concrete, induce stress/strain redistributions in post-tensioned concrete bridges that must be taken into account during their design. The underestimation of time-dependent effects can negatively influence the load-deformation behavior of this bridge typolo...

Leakage in buried pipes is the main source of wastage in water distribution systems. The issue of promptly pinpointing and fixing the leaks is thus of great interest to minimize water wastage. One way to pinpoint a leakage is to measure two acoustic signals, on the pipe, one each side of the leak an...

Safety-critical composite structures are prone to barely visible damages which do not manifest themselves in the global structural response. Acousto-ultrasonic techniques have been utilized to identify these damages, but the problem is extremely challenging on multiple fronts. Com-posite waveguides ...

Automated operational modal analysis (AOMA) of civil engineering structures and suspension bridges based on vibrational monitoring data is now regularly performed to extract the modal features of these structures, on which structural health monitoring is performed and the state of the infrastructure...

Modal parameters estimated through in field dynamic testing define the inherent characteristics of real-world structures, being therefore employed as reference information for various purposes, including the assessment of structural damage, the evaluation of operational and environmental effects, an...

Among the compendium of highway civil infrastructures built in the last decades, many repetitive or quasi-periodic configurations can be found, such as multi-span simply supported bridges. Structural Health Monitoring (SHM) strategies for this kind of structures should properly consider such structu...

This work present an innovative technique that helps to accelerate structural dynamics simulations when there is a defect in the structure and at the same time, allows its approximation in a parametric way by using reduced models. These developments open the door to the introduction of robust hybrid...

. Vibration analysis is highly beneficial in a variety of engineering areas. However, in many real-world applications, vibration data acquisition may be challenging due to the accessibility of the desired sensor locations. It can be also costly if many measurement points are required. Consequently, ...

In Cahora Bassa dam, a 170m-high arch dam located in western Mozambique, a system for vibrations monitoring of the type SSHM (Seismic and Structural Health Monitoring) was installed in 2010. The dam, in operation since 1974, is affected by a swelling process of small/medium amplitude. Aiming to cont...

In the context of Structural Health Monitoring, the accurate estimation of the state of a structural system subjected to various sources of dynamic loads can be beneficial for assessing the current structural performance and for predicting the future one. In case of linear systems, for example, the ...

Structural health monitoring (SHM) is an important approach in order to evaluate the health state and so the safety and security of structures as bridges. It also helps to maintain and to extend their lives, to detect and predict their failures. This approach regroups several techniques such as vibr...

The transmissibility function (TF) has been widely reported to be a damage-sensitive but excitation-insensitive damage feature. However, most TF-based novelty detection approaches fail to accommodate various uncertainties with a proper probabilistic model. Making full use of the multivariate complex...

Leaks in water distribution mains are a big problem, with around 20% of supplied potable water lost to leaks during transport. Correlation-based acoustic techniques have provided an accurate and non-invasive way of detecting and locating these leaks for a few decades. These methods have almost exclu...

The build-up of ice on the blades is a known issue for wind turbine operators. In particularly in northernly countries continued operation under icing can lead to significant performance losses and increased wear of key components. Aside from the operational concerns the ice also poses a potential s...

When performing modal identification of structural systems, the main goal is to accurately extract the modal properties from the measured vibration data. The system identification can be carried out either in time or frequency-domain depending on the primary data used in the identification process, ...

We propose an approach to define alarm thresholds for vibration-based structural health monitoring (SHM) systems. The approach uses the frequencies of vibration, generally estimated from recorded accelerations, and it is based on the concept of Minimum Detectable Damage (MDD), namely the smallest da...

The determination of the mass density of a taut vibrating membrane from measurements of resonant frequency values (eigenvalues) is a problem of practical interest in various areas of applied science, from structural mechanics to biology. The inverse problem that arises is of great mathematical diffi...

Operational modal analysis is a technique developed to estimate the modal parameters of a given structural or mechanical system using vibration data recorded with sensors. There are many approaches to the problem: parametric and non-parametric; time domain and frequency domain; maximum likelihood an...

Masonry vaults represent one of the most recurrent types of horizontal structural elements in architecture in European countries, even in areas characterized by a high level of seismic risk. Therefore, the evaluation of their structural safety and their mechanical behaviour remains of primary import...

Over the past few decades, vibration-based structural health monitoring and damage detection have drawn significant research attentions world-wide. The major motivation for such a research emphasis is the need to develop reliable methods to monitor the performance of structures in real-time. Real-ti...

System identification on operational structures is made difficult by the lack of information regarding the structure and the input force. Output-only system identification methods exist as a way of inferring the system and input force, given the output of the system which can be readily measured. Wi...

Space truss structures are a type of versatile lightweight systems that are applied in different fields such as civil and aerospace engineering. For some of these systems that were built decades ago, for example as roof structures for relatively large spans, not all proofs regarding the load-bearing...

When dealing with cable-suspended structures, it is essential to have an accurate estimation of the tensile force on cable elements. This is firstly to guarantee the structural safety of the structure but also to allow scheduling of the maintenance operations. Being the direct measurement often rela...

The comfort and stability of maglev train depends on the suspension gap between bogie and rail, which should be strictly restricted in a certain range, usually 8 to 10 millimeters, by using the suspension controller. However, this restriction may become unstable due to the influence of external dist...

Vibration-based Structural Health Monitoring (SHM), exploits a variety of approaches for novelty detection. In particular, some data-based methods try to recognise patterns by exploiting analogies with the human body’s natural defences at a cellular level. These algorithms often require the use of...