1,721,057 research outputs found
Sustainable countermeasures for rockfall risk management
No full textRockfall is one of the most frequent geological hazard, whose related risk can be particularly high in areas crossed by roads and railway arteries and characterized by densely populated towns and tourist infrastructures. Owing to the ever increasing urban expansion as well as climate changes, the interference between human activities and natural events has considerably grown in these areas. In this paper the use of low environmental impact countermeasures and appropriate tools for landslide risk analysis and management is presented and discussed, with special reference to the falling rock protection barriers, effective and widely used protection systems against rockfalls
A numerical investigation on the yield surface for shallow foundations embedded in sand
No full textThis paper presents a numerical study on the drained response of a shallow foundation subjected to planar combined loads. Plane strain conditions are assumed and different initial foundation depths and values of vertical penetration are considered. Data from centrifuge experiments of surface and buried foundations available in literature, are used to assess the ability of the model to reproduce the essential features of the experimentally observed behaviour. Interpreted within the context of existing work-hardening plasticity models applied to the soil-foundation system and presented in terms of loadâdisplacement curves and load paths, the results of the numerical analyses provide new evidence of the effects of the embedment on the yield surface for a shallow foundation
Caisson Foundations for Competitive Offshore wind Farms in ITALY
No full textAbstractThe research presented in the paper moves from the results of a feasibility study recently carried out for the development of an offshore wind farm off the cost of Rimini, in the Northern Adriatic Sea. The work, based on in-situ measurements of the environmental conditions, assessed the suitability of the considered area for the development of a relatively large wind farm, although at the profitability limit. The study has considered 60 offshore wind turbines installed on monopiles, as they are, at present, the most common solution and a quantification of the investment costs could be reliably completed. With reference to such case, the paper addresses the use of caisson foundations, a convenient alternative to monopiles in water of shallow to intermediate depth, with the final aim of improving the overall cost-effectiveness of the investment
The role of rockfall protection barriers in the context of risk mitigation: The case of the autonomous province of bolzano
No full textMetamodeling to emulate plate anchor response in spatially variable soil
No full textThis paper describes a metamodelling approach to investigate the behaviour of a plate anchor in spatially variable soil. The approach explores the effect of variability in undrained shear strength on the monotonic holding capacity. The problem is firstly analysed through a selected number of two-dimensional finite element (FE) analyses. As this is computationally expensive, relatively few analyses are performed, with the metamodel developed to map the response over a wider range of parameters. This uses mathematical operators calibrated to emulate the FE models, which can be built on a relatively small data set, with the overall objective to retain the accuracy of the original FE model at negligible computational cost. In future, this approach may support design by considering uncertainties that are common for any offshore foundation problem, providing a tool that can be easily coupled with traditional probabilistic design approaches
Investigating the behaviour of existing rockfall protection barriers
No full textThe development of advanced full-scale testing facilities and numerical models has greatly supported the development and the improvement of new rockfall protection barriers (Volkwein et al., 2011), light and versatile steel structures, now capable to arrest falling blocks having capacity up to 8000 kJ. However, the management of existing and comparatively older rockfall protection barriers still remains a crucial issue, notably when rockfall risk assessment is performed along slopes where these structures are found (Bourrier et al., 2014). Within the context, this short note addresses the study of these protection structures, with reference to the case study of the Autonomous Province of Bolzano (PAB)
A load-transfer curve formulation to predict the drained response of offshore piles to pull-out
Full text linkThe study introduces a formulation for load-transfer curves t-z to predict the load-displacement behaviour of offshore steel piles subjected to axial tensile loading. This condition is particularly relevant to foundations for wind turbines in intermediate to deep water, supporting jackets or anchoring floating structures. The problem is first addressed using a continuum approach implemented with the finite element method. Interface behaviour is modelled using the results of interface tests. Available data from pile tests, featuring different geometries, are used to assess the model ability to reproduce the experimentally observed response. The results of the finite element analyses are then used to develop and calibrate the t-z curves, which are implemented in a simpler one-dimensional finite element model. The comparison of the results of the two-dimensional and one-dimensional approaches shows good agreement. It is also shown that the one-dimensional approach can be successfully implemented using the equations of the recently developed unified CPT method
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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