Elena Blanco-Fernandez

Design and Evaluation of Two Laboratory Tests for the Nets of a Flexible Anchored Slope Stabilization System

This paper evaluates two new tests to characterize cable nets used in slope stabilization; a concentrated load test (CLT) and a distributed load test (DLT). These tests enable engineers to obtain the stress versus displacement graph and the maximum resistance. Both test devices and test methodology have been designed by the Construction Technology Research Group (GITECO) at the University of Cantabria. These two tests have enabled the certification of two different manufacturers of cable nets, Geobrugg and Malla Talud Cantabria (MTC). The results showed that these tests provide representative results of the net resistance. To verify the effectiveness of these new tests, they have been performed with various cable nets, from which homogeneous, logical results have been obtained, which are representative of the real working conditions. When performing the distributed load test, the force was applied to a pyramid of fine gravel sacks that enabled the forces to be distributed throughout the net. With this configuration, the net was deformed, acquiring an elliptical form in the lower free area. In the concentrated load test, the force was applied through a metallic plate of 600 mm diameter that deformed the net locally. The result always showed homogeneous behavior of the different samples tested. This allowed the test to be repeated in the same conditions several times. With the results of both tests an analysis was carried out relating the net grid, the load applied, and the displacement obtained. This enabled the generation of regression functions that provided information about the resistance value and the net displacement according to the chosen grid.

Energy Dissipating Devices in Falling Rock Protection Barriers

Rockfall is a phenomenon which, when uncontrolled, may cause extensive material damage and personal injury. One of the structures used to avoid accidents caused by debris flows or rockfalls is flexible barriers. The energy dissipating devices which absorb the energy generated by rock impact and reduce the mechanical stresses in the rest of the elements of the structure are an essential part of these kinds of structures. This document proposes an overview of the performance of energy dissipating devices, as well as of the role that they fulfil in the barrier. Furthermore, a compilation and a description of the dissipating elements found in the literature are proposed. Additionally, an analysis has been performed of the aspects taken into account in the design, such as experimental (quasi-static and dynamic) tests observing the variation of the behaviour curve depending on the test speed and numerical simulations by means of several finite element software packages.

Decision aid system founded on nonlinear valuation, dispersion-based weighting and correlative aggregation for wire rope selection in slope stability cable nets

A decision aid system to address hierarchical decision-making problems is developed.Levels of satisfaction are valuated using the Beta Cumulative Distribution Function.Subcriteria are weighted based on their variability using measures of dispersion.Dependencies between subcriteria are quantified through correlation coefficients.The system is applied to the selection of wire rope in slope stability cable nets. This paper presents a decision aid system to address hierarchically structured decision-making problems based on the determination of the satisfaction provided by a group of alternatives in relation to multiple conflicting subcriteria grouped into criteria. The system combines the action of three new methods related to the following concepts: nonlinear valuation, dispersion-based weighting and correlative aggregation. The first includes five value functions that allow the conversion of the ratings of the alternatives regarding the subcriteria into the satisfaction they produce in a versatile and simple manner through the Beta Cumulative Distribution Function. The use of measures of dispersion to weight the subcriteria by giving more importance to those factors that can make a difference due to their heterogeneity is revised to validate it when the values are not normally distributed. Dependencies between subcriteria are taken into account through the determination of their correlation coefficients, whose incorporation adjusts the results provided by the system to favour those alternatives having a balanced behaviour with respect to conflicting aspects. The overall satisfaction provided by each alternative is determined using a prioritisation operator to avoid compensation between criteria when aggregating the subcriteria. The system was tested through a novel field of application such as the selection of wire rope to form slope stability cable nets.

Energy harvesting from vehicular traffic over speed bumps: a review

Energy used by vehicles to slow down in areas of limited speed is wasted. A traffic energy-harvesting device (TEHD) is capable of harvesting vehicle energy when passing over a speed bump. This pape...