A comparison between the MEXE and Pippard's methods of assessing the load carrying capacity of masonry arch bridges

The Military Engineering eXperimental Establishment (MEXE) method is a long established system of masonry arch load carrying capacity assessment. It has been subject to review in recent years and some shortcomings have been identified. There is now growing consensus that the current version of MEXE overestimates the load carrying capacity of short span bridges, but for spans over 12m it becomes increasingly conservative. In this paper Pippard’s elastic method and the MEXE method are used to investigate the significance of factors such as fill cover, ring thickness and effective width of arch barrel, and their effect upon the load-carrying capacity predictions in short and long span arches. Conclusions are drawn which establish directions of new research and offer guidance to assessors of short and long span masonry arch bridges

Three applications of augmented reality technologies in structural engineering education

In technology terms, a real environment or personal space that is altered with digital media, such as images, is termed Augmented Reality (A.R.). From 2020 onwards, the next big thing in the technology sector will be A.R. The purpose of the current paper was to get ahead of the technology curve and develop applications of A.R. which could be used within structural engineering education both now and in the future. Three applications are presented. The first was a walking map/tour of Manchester and its buildings and bridges, whereby, at each stop, the tour is augmented with explanatory videos showing, amongst other things, structural load paths superimposed onto the actual structure. The second application was a structural engineering laboratory exercise that was augmented with videos explaining how to set up and use the apparatus from start to finish. The intention was to replace Lecturer/Technician assistance and make the exercise self-supporting. The final application used 360° video footage of a real construction site that was augmented with H&S/C.D.M. information. A unique 360° media suite at the University of Salford was used to display the video footage, which aided group work and also had a gaming element to the exercise whereby an X-box style controller was used to ‘point and shoot’ at perceived hazards and, if correct, pop ups would be revealed which would give mitigation measures and C.D.M. information. Quantative and qualitative means were used to measure the effectiveness of each application, with the general conclusion that further and continual refinement of the A.R. content would enhance effectiveness. There were no qualitative comments on the effectiveness of the technology, which implies that participants had few concerns about using the technology. There is promising potential of applying A.R. in structural engineering education in the future

Formative assessment that bites

It is now an established fact that the learning cycle is greatly enhanced by timely and effective feedback. The use of formative assessment has now become an indispensable vehicle to facilitate student engagement in the feedback process, even if they do not recognise they are receiving feedback. This paper presents a review of some formative feedback events, in which civil engineering students at The University of Salford participate. The cohorts studied cross six years (200+ students), and three programmes at FHEQ level 7. The study indicates that carefully designed feedback events can have a significant impact upon understanding of structural behaviour for students preparing for professional status

Moisture susceptibility and fatigue performance of hydrated lime-modified asphalt concrete : experiment and design application case study

Hydrated lime has been recognized as an effective additive used to improve asphalt concrete properties in pavement applications. However, further work is still needed to quantify the effect of hydrated lime on asphaltic concrete performance under varied weather, temperature and environmental conditions and in the application of different pavement courses. A research project has been conducted using hydrated lime to modify the asphalt concretes used for the applications of wearing (surface), levelling (binder) and base courses. A previous publication has reported the experimental study on the resistance to Marshall stability and the volumetric properties, the resilient modulus and permanent deformation at three different weather temperatures. This paper reports the second phase experimental study for material durability, which investigated the effect of hydrated lime content on moisture susceptibility when exposed to a freeze-thaw cycle, and the fatigue life. The experimental results show an improvement in the durability of the modified asphalt concrete mixtures. Optimum hydrated lime contents for different course applications are suggested based on the series experimental studies. Finally, the advantage of using the optimum mixtures for a pavement application is demonstrated

Dealing with blast loading on brickwork

Much effort is being deployed in maintaining electricity generation from the UK's fleet of nuclear power stations with safety being a prime consideration. Up-to-date safety standards demand resistance to hazards which normally include seismic and blast loading, yet many stations were built before such considerations became mandatory. To extend the generating life of older nuclear power stations, a demonstration of conformity to modern safety standards is now required. This paper will discuss the structural problems associated with assessing and strengthening masonry panels subjected to blast loadings as generated by a postulated accident of hot gas release from fracture of a reactor pressure vessels cooling circuit. The paper will provide background on masonry strength and assessment techniques, including the use of dynamic amplification which permits static design principles to be used under dynamic loading conditions. An account of the strengthening options and the problems associated with their implementation will be presented

A sustainable pavement concrete using warm mix asphalt and hydrated lime treated recycled concrete aggregates

Recently, increasing material prices coupled with more acute environmental awareness and the implementation of regulation has driven a strong movement toward the adoption of sustainable construction technology. In the pavement industry, using low temperature asphalt mixes and recycled concrete aggregate are viewed as effective engineering solutions to address the challenges posed by climate change and sustainable development. However, to date, no research has investigated these two factors simultaneously for pavement material. This paper reports on initial work which attempts to address this shortcoming. At first, a novel treatment method is used to improve the quality of recycled concrete coarse aggregates. Thereafter, the treated recycled aggregates were used in warm mix asphalt at varied rates to replace virgin raw coarse aggregates. The asphalt concrete mixes produced were tested for modulus, tensile strength, permanent deformation, moisture susceptibility and fatigue life. The comparison of these properties with that of the mixes using the same rates of untreated course aggregates from the same source has demonstrated the effectiveness of the new technology. Lastly, the cost, material and energy saving implications are discussed

Optimal search strategies for identifying sound clinical prediction studies in EMBASE

BACKGROUND: Clinical prediction guides assist clinicians by pointing to specific elements of the patient's clinical presentation that should be considered when forming a diagnosis, prognosis or judgment regarding treatment outcome. The numbers of validated clinical prediction guides are growing in the medical literature, but their retrieval from large biomedical databases remains problematic and this presents a barrier to their uptake in medical practice. We undertook the systematic development of search strategies ("hedges") for retrieval of empirically tested clinical prediction guides from EMBASE. METHODS: An analytic survey was conducted, testing the retrieval performance of search strategies run in EMBASE against the gold standard of hand searching, using a sample of all 27,769 articles identified in 55 journals for the 2000 publishing year. All articles were categorized as original studies, review articles, general papers, or case reports. The original and review articles were then tagged as 'pass' or 'fail' for methodologic rigor in the areas of clinical prediction guides and other clinical topics. Search terms that depicted clinical prediction guides were selected from a pool of index terms and text words gathered in house and through request to clinicians, librarians and professional searchers. A total of 36,232 search strategies composed of single and multiple term phrases were trialed for retrieval of clinical prediction studies. The sensitivity, specificity, precision, and accuracy of search strategies were calculated to identify which were the best. RESULTS: 163 clinical prediction studies were identified, of which 69 (42.3%) passed criteria for scientific merit. A 3-term strategy optimized sensitivity at 91.3% and specificity at 90.2%. Higher sensitivity (97.1%) was reached with a different 3-term strategy, but with a 16% drop in specificity. The best measure of specificity (98.8%) was found in a 2-term strategy, but with a considerable fall in sensitivity to 60.9%. All single term strategies performed less well than 2- and 3-term strategies. CONCLUSION: The retrieval of sound clinical prediction studies from EMBASE is supported by several search strategies

Optimal search strategies for detecting cost and economic studies in EMBASE

BACKGROUND: Economic evaluations in the medical literature compare competing diagnosis or treatment methods for their use of resources and their expected outcomes. The best evidence currently available from research regarding both cost and economic comparisons will continue to expand as this type of information becomes more important in today's clinical practice. Researchers and clinicians need quick, reliable ways to access this information. A key source of this type of information is large bibliographic databases such as EMBASE. The objective of this study was to develop search strategies that optimize the retrieval of health costs and economics studies from EMBASE. METHODS: We conducted an analytic survey, comparing hand searches of journals with retrievals from EMBASE for candidate search terms and combinations. 6 research assistants read all issues of 55 journals indexed by EMBASE for the publishing year 2000. We rated all articles using purpose and quality indicators and categorized them into clinically relevant original studies, review articles, general papers, or case reports. The original and review articles were then categorized for purpose (i.e., cost and economics and other clinical topics) and depending on the purpose as 'pass' or 'fail' for methodologic rigor. Candidate search strategies were developed for economic and cost studies, then run in the 55 EMBASE journals, the retrievals being compared with the hand search data. The sensitivity, specificity, precision, and accuracy of the search strategies were calculated. RESULTS: Combinations of search terms for detecting both cost and economic studies attained levels of 100% sensitivity with specificity levels of 92.9% and 92.3% respectively. When maximizing for both sensitivity and specificity, the combination of terms for detecting cost studies (sensitivity) increased 2.2% over the single term but at a slight decrease in specificity of 0.9%. The maximized combination of terms for economic studies saw no change in sensitivity from the single term and only a 0.1% increase in specificity. CONCLUSION: Selected terms have excellent performance in the retrieval of studies of health costs and economics from EMBASE

Implementing the MOVE! Weight-Management Program in the Veterans Health Administration, 2007-2010: A Qualitative Study

IntroductionOne-third of US veterans receiving care at Veterans Health Administration (VHA) medical facilities are obese and, therefore, at higher risk for developing multiple chronic diseases. To address this problem, the VHA designed and nationally disseminated an evidence-based weight-management program (MOVE!). The objective of this study was to examine the organizational factors that aided or inhibited the implementation of MOVE! in 10 VHA medical facilities.MethodsUsing a multiple, holistic case study design, we conducted 68 interviews with medical center program coordinators, physicians formally appointed as program champions, managers directly responsible for overseeing the program, clinicians from the program's multidisciplinary team, and primary care physicians identified by program coordinators as local opinion leaders. Qualitative data analysis involved coding, memorandum writing, and construction of data displays.ResultsOrganizational readiness for change and having an innovation champion were most consistently the 2 factors associated with MOVE! implementation. Other organizational factors, such as management support and resource availability, were barriers to implementation or exerted mixed effects on implementation. Barriers did not prevent facilities from implementing MOVE! However, they were obstacles that had to be overcome, worked around, or accepted as limits on the program's scope or scale.ConclusionPolicy-directed implementation of clinical weight-management programs in health care facilities is challenging, especially when no new resources are available. Instituting powerful, mutually reinforcing organizational policies and practices may be necessary for consistent, high-quality implementation