1,721,006 research outputs found
Numerical modelling-based sensitivity analysis of fluvial morphodynamics
No full textThis study's objective is to assess the sensitivity analysis' potential for application in the context of the stochastic-input based modelling of fluvial morphodynamics. The corresponding work involved (1) an analysis of the work available in the literature and (2) an independent application of sensitivity analysis for comparison. The application of sensitivity analysis was accomplished by using a numerical hydro-morphodynamic model to represent the natural morphodynamical processes' response to the uncertainty in a selected set of variables. The resulting morphodynamical sensitivities were quantified and a characterization of the relationship between the variables' effects and morphodynamics was produced. The potential generalization of the results of sensitivity analysis for the purposes of validating stochastic modelling across different case studies was assessed. Resulting sensitivities were found to be strongly case-specific with little generalization potential, indicating that sensitivity analysis in the context of fluvial morphodynamics is likely of little scientific interest
Comment on "Pressure fluctuations on plunge pool floors" (by Ervine D.A. Falvey H.T. and Withers W.)
No full textTurbulent stresses at the bottom surface near an abutment: a laboratory-scale numerical experiment
No full textInvited perspectives: When research meets practice: challenges, opportunities, and suggestions from the implementation of the Floods Directive in the largest Italian river basin
Full text linkThe paper discusses challenges (and solutions) emerged during a collaboration among practitioners, stakeholders, and scientists in the definition of flood damage maps in the Po River District. Social aspects were proven to be fundamental components of the risk assessment; variety of competences in the working group was key in finding solutions and revealing weaknesses of intermediate proposals. This paper finally highlights the need of duplicating such an experience at a broader European level
Actions monitoring as an alternative to structural rehabilitation: Case study of a river bridge
No full textA number of river bridges collapse worldwide every year during flood events, due to combination of actions including traffic loads, water and wind load, riverbed degradation, and accumulation of debris. Incidence of failure is higher for relatively old bridges that may have been designed without adequate consideration for some of such actions, in particular the scour potential at piers and abutments; in this case, consolidation of bridge foundations may be required. As an alternative to structural rehabilitation, we propose here real-time management as a nonstructural risk-mitigation measure: Data from a monitoring system aid the bridge managers to decide whether a bridge should be partially or totally closed to traffic in the case that forecasted environmental conditions indicate that the structure may exit its safe operational domain. A peculiar feature of the present proposal is that the monitoring system focuses on the evaluation of the environmental actions on the structure rather than on the health state of the structure itself: Such choice allows sufficient lead time for bridge closure. Bridge management may not prevent the damage of the structure but should avoid casualties. The methodology is presented with reference to the field case of a bridge over the river Po (Italy); its generalization to a larger variety of conditions is also discussed
Gap effect on transversal force acting on infinite array of cylinders at low KC and beta
No full textStatic monitoring of a masonry arch bridge: Evaluating the effects of changing environment
Full text linkContinuous Monitoring of Masonry Arch Bridges to Evaluate the Scour Action
Full text linkThe shallow foundations that often characterizes multi-span masonry arch bridges are highly vulnerable to the soil settlements typically induced by riverbed scouring. Consequently, monitoring of scouring effects is of paramount importance to ensure the safe operation of these river bridges. Within a recent collaboration between Politecnico di Milano and Regione Lombardia, a multi-span masonry arch bridge has been selected to exemplify a quasi-static monitoring strategy capable of detecting the flood-induced scour. The structure, built during the second half of the 19th century, was subjected to numerous strengthening interventions, especially on the pier foundations resting on the riverbed. The installed heterogeneous sensor network consists of tiltmeters (measuring the rotation of the piers at the skewback level), 1 weather station, 1 hydrometer, and 1 echo-sounder. In addition, the detection of debris accumulation is performed with cameras taking pictures of the piers from the upstream side. After a concise description of the structure and the Sesia River, the paper focuses on the adopted measuring system and the results obtained in the first months of continuous monitoring
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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