Pervasive Fibre-optic sensor networks in bridges: A UK case study

© 2018 Taylor & Francis Group, London. Integrating fibre-optic sensor networks in a newly-constructed infrastructure assets enables datadriven performance assessment during its construction and throughout its operational life. As part of a multimillion pound railway infrastructure redevelopment project, two new railway bridges were instrumented with an extensive network of both discrete (fibre Bragg gratings or FBGs) and distributed (based on Brillouin optical time domain reflectometry or BOTDR) fibre optic sensors to measure both strain and temperature throughout construction and in-service. Completed in 2016 in Staffordshire UK, both ‘self-sensing’ bridges contain more than 500 fibre Bragg grating sensors and over 600 metres of distributed fibre optic sensor cabling. This paper describes the sensing technologies employed, installation techniques for improving sensing robustness, the monitoring programme and objectives, data processing methods and assumptions, and the primary monitoring findings of this project. Results related to measurements of prestress losses in prestressed concrete girders, estimates of steel girder deflection using FBGs and videogrammetry, and assessments of percentage utilization of critical superstructure elements are presented. In terms of future directions, BIM-based environments which incorporate sensor elements and an emerging field of research known as Data-Centric Engineering are introduced as tools to better manage, maintain and learn from the information generated from self-sensing infrastructure.EPSRC, Innovate UK and the Lloyd's Register Foundation for funding this research through the Centre for Smart Infrastructure and Construction (CSIC) Innovation and Knowledge Centre and the Alan Turing Institute

Deformation of an elastic beam on a winkler foundation

AbstractWe present a simple model for geophysical systems involving sources of deformation, such as magmatic intrusions, subglacial lakes, and the subsurface storage of CO2. We consider the idealized system of a uniform elastic layer overlying a localized region of constant pressure that is surrounded by a Winkler foundation composed of springs. We investigate the effect of source depth and foundation stiffness on the resulting displacement profiles at both the surface and the level of the source. The system is characterized by three key features: the maximum uplift, the maximum subsidence, and the distance to the point of zero displacement. For each of these, we determine asymptotic scaling behavior in the limits of a thin/thick layer and a soft/stiff foundation and form composite curves that allow specific parameter values to be determined from field data. Both two-dimensional and axisymmetric pressure patches are considered, and in the thin-layer limit we derive analytical solutions.</jats:p

Implementing bridge model updating for operation and maintenance purposes: examination based on UK practitioners’ views

There has been a vision of creating bridge digital twins as virtual simulation models of bridge assets to facilitate remote management. Bridge model updating is one digital twin technology which can enable the continuous updating of the structural model as new monitoring data is collected. This paper examines why there is currently little industry uptake of monitoring, modelling and model updating for the operation and maintenance of bridges despite over two decades of research in these fields. The study analyses the findings from a series of semi-structured industry interviews with expert bridge professionals in the U.K. and from an extensive literature survey of bridge model updating studies to examine the disconnects between research and practice and the practical issues of implementing bridge model updating. In particular, the study found that localised damage resulting in local reduction in structural stiffness, a key assumption made in the majority of research, is subject to question by practitioners as many common types of bridge damage may not induce noticeable change in structural stiffness that existing model updating techniques would identify. Key recommendations for future research are proposed to drive adoption of bridge monitoring, modelling and model updating and thus realise their industrial value

Quality of life can be good after slide tracheoplasty for long-segment tracheal stenosis

OBJECTIVES: The objectives of this study were to measure 'health-related quality of life' (HRQoL) in children following slide tracheoplasty for long-segment tracheal stenosis (LSTS) and to explore the relationship of comorbidities and parental mental health with HRQoL outcomes. METHODS: A cross-sectional study was undertaken with children who had undergone slide tracheoplasty. Participants included parents and children (age 5-15 years) recruited over a 13-month period, who were asked to complete validated measures of HRQoL, development and behaviour. Scores were compared to published norms. RESULTS: Forty-two children (male 69%; n = 29) were included; mean age was 5.3 (standard deviation 3.5) years and mean follow-up was 45 (range 4-179) months. Mean total HRQoL scores for children with repaired LSTS did not differ from those of healthy norms other than for children aged 13-23 months, but 10 children (24%) had scores >2 SD below the mean for healthy children. HRQoL was poorer in children with non-cardiac congenital comorbidities than in those with isolated LSTS (mean scores 60.34 ± 17.19 and 85.52 ± 12.19, respectively, P = 0.01). There was good agreement between children's and parents' scores, although children rated their HRQoL as better than their parents did. Anxious parents rated their children's HRQoL as significantly worse than non-anxious parents (P<0.001). CONCLUSIONS: Older children with isolated LSTS can have excellent HRQoL after surgery. Younger children, at an earlier time point postoperatively, and those with non-cardiac congenital comorbidities have poorer HRQoL. Further longitudinal evaluation is required to identify psycho-social (including parental) predictors of outcome which may inform, or be amenable to, intervention

Airway tissue engineering for congenital laryngotracheal disease

Regenerative medicine offers hope of a sustainable solution for severe airway disease by the creation of functional, immunocompatible organ replacements. When considering fetuses and newborns, there is a specific spectrum of airway pathologies that could benefit from cell therapy and tissue engineering applications. While hypoplastic lungs associated with congenital diaphragmatic hernia (CDH) could benefit from cellular based treatments aimed at ameliorating lung function, patients with upper airway obstruction could take advantage from a de novo tissue engineering approach. Moreover, the international acceptance of the EXIT procedure as a means of securing the precarious neonatal airway, together with the advent of fetal surgery as a method of heading off postnatal co-morbidities, offers the revolutionary possibility of extending the clinical indication for tissue-engineered airway transplantation to infants affected by diverse severe congenital laryngotracheal malformations. This article outlines the necessary basic components for regenerative medicine solutions in this potential clinical niche

Use of Simulation to Visualize Healthcare Worker Exposure to Aerosol in the Operating Room

Simulation resources offer an opportunity to highlight aerosol dispersion within the operating room environment. We demonstrate our methodology with a supporting video that can offer operating room teams support in their practical understanding of aerosol exposure and the importance of personal protective equipment

A case of PTSD presenting with psychotic symptomatology: a case report

A male patient aged 43 presented with psychotic symptomatology after a traumatic event involving accidental mutilation of the fingers. Initial presentation was uncommon although the patient responded well to pharmacotherapy. The theoretical framework, management plan and details of the treatment are presented

Ultrasound neuromodulation: a review of results, mechanisms and safety

Ultrasonic neuromodulation is a rapidly growing field, in which low-intensity ultrasound (US) is delivered to nervous system tissue, resulting in transient modulation of neural activity. This review summarizes the findings in the central and peripheral nervous systems from mechanistic studies in cell culture to cognitive behavioral studies in humans. The mechanisms by which US mechanically interacts with neurons and could affect firing are presented. An in-depth safety assessment of current studies shows that parameters for the human studies fall within the safety envelope for US imaging. Challenges associated with accurately targeting US and monitoring the response are described. In conclusion, the literature supports the use of US as a safe, non-invasive brain stimulation modality with improved spatial localization and depth targeting compared with alternative methods. US neurostimulation has the potential to be used both as a scientific instrument to investigate brain function and as a therapeutic modality to modulate brain activity