A field experiment on a steel Gerber-truss bridge for damage detection utilizing vehicle-induced vibrations

A field experiment was conducted on a real continuous steel Gerber-truss bridge with artificial damage applied. This article summarizes the results of the experiment for bridge damage detection utilizing traffic-induced vibrations. It investigates the sensitivities of a number of quantities to bridge damage including the identified modal parameters and their statistical patterns, Nair’s damage indicator and its statistical pattern and different sets of measurement points. The modal parameters are identified by autoregressive time-series models. The decision on bridge health condition is made and the sensitivity of variables is evaluated with the aid of the Mahalanobis–Taguchi system, a multivariate pattern recognition tool. Several observations are made as follows. For the modal parameters, although bridge damage detection can be achieved by performing Mahalanobis–Taguchi system on certain modal parameters of certain sets of measurement points, difficulties were faced in subjective selection of meaningful bridge modes and low sensitivity of the statistical pattern of the modal parameters to damage. For Nair’s damage indicator, bridge damage detection could be achieved by performing Mahalanobis–Taguchi system on Nair’s damage indicators of most sets of measurement points. As a damage indicator, Nair’s damage indicator was superior to the modal parameters. Three main advantages were observed: it does not require any subjective decision in calculating Nair’s damage indicator, thus potential human errors can be prevented and an automatic detection task can be achieved; its statistical pattern has high sensitivity to damage and, finally, it is flexible regarding the choice of sets of measurement points.

An Assessment of Psychological Need in Emergency Medical Staff in the Northern Health and Social Care Trust Area

Setting: Psychological stress is increasingly recognised within emergency medicine, given the environmental and clinical stressors associated with the specialism. The current study assessed whether psychological distress is experienced by emergency medical staff and if so, what is the expressed need within this population? Participants: Participants included ambulance personnel, nursing staff, doctors and ancillary support staff within two Accident and Emergency (A&E) departments and twelve ambulance bases within one Trust locality in NI (N = 107). Primary and secondary outcome measures: The General Health Questionnaire (GHQ-12, Goldberg, 1972, 1978), Secondary Traumatic Stress Scale (STSS, Bride, 2004) and an assessment of need questionnaire were completed and explored using mixed method analysis. Results: Results showed elevated levels of psychological distress within each profession except ambulance service clinical support officers (CSOs). Elevated levels of secondary trauma symptomatology were also found; the highest were within some nursing grades and junior doctors. Decreased enjoyment in job over time was significantly associated with higher scores. Analysis of qualitative data identified sources of stress to include low morale. A total of 65% of participants thought that work related stressors had negatively affected their mental health. Participants explored what they felt could decrease psychological distress including improved resources and psychoeducation. Conclusion: There were elevated levels of distress and secondary traumatic stress within this population as well as an expressed level of need, on both systemic and support levels.