Artículos (Estructuras de Edificación e Ingeniería del Terreno)
https://hdl.handle.net/11441/24701
2024-03-19T11:37:30ZDynamic analysis of the Almagrera tailings dam with dry closure condition
https://hdl.handle.net/11441/156194
Dynamic analysis of the Almagrera tailings dam with dry closure condition
In light of growing concerns over sustainability, particularly in the wake of environmental disasters like the Aznalcollar dam break, the Spanish authorities have heightened their awareness of issues surrounding ore tailings management. The main aim of this paper is to study the dynamic behavior for the dry closure of the Almagrera dam under the action of an earthquake. This study was carried out with the Plaxis 2D v9.02 program, which uses the finite element (FE) method. The dynamic analysis of the dam was interpreted in terms of deformations, displacements and principal stresses. The construction of the Uniform Seismic Hazard Acceleration Response Spectrum (USHARS) and the selection of real accelerograms for the time-history dynamic calculations is a noted feature of this research. Numerical analyses show that the dam is safe enough because a failure surface has not been formed, although several plastic zones may appear in the dam. The FE study of deformations display that the tailings may attain large deformations, displacements and failure, although this does not jeopardize the safety of the dam where the displacements are smaller than 3 mm. Neither the tailings nor the dam are expected to suffer liquefaction. It was determined that the 0.09 g threshold value is not exceeded in the acceleration-time graphs on the old reservoir field surface, which is the most critical situation.
2024-02-15T00:00:00ZLa modelización de los pilotes en el método de elementos finitos (EF)
https://hdl.handle.net/11441/155465
La modelización de los pilotes en el método de elementos finitos (EF)
Este artículo presenta una descripción detallada de las ventajas e inconvenientes de los pilotes volumétricos y embebidos. La dependencia de los resultados del tamaño de la malla es más significativa en el pilote embebido. Para grupos numerosos de pilotes, la cantidad de elementos en el sistema se reduce significativamente usando pilotes embebidos. Se han comparado los resultados obtenidos con ambos modelos con los datos obtenidos de ensayos de carga a escala real en un caso de estudio de un pilote hincado prolongado con un micropilote, sometido a compresión, tracción y cortantes (caso 1) y con los resultados de un análisis elastoplástico, realizado con un método establecido, como es el de la ecuación integral (caso2). En el caso 1, los resultados para el pilote a compresión revelaron que el pilote volumétrico puede reproducir el escalón que se produce cuando hay un cambio en la sección del pilote, algo que no es posible con un pilote embebido. Para carga axial de tracción y carga lateral, el pilote embebido reproduce mejor el desplazamiento medido en la cabeza del pilote o la distribución de esfuerzos a lo largo del mismo. Las conclusiones obtenidas se refieren principalmente a los tipos de modelización numérica descritos en el texto del artículo y a los programas en que se aplican.; This paper presents a detailed description of the relative advantages and disadvantages of volume piles and embedded piles. The mesh dependency is more significant in an embedded pile. When a large number of piles have to be considered, the number of elements in the system is significantly reduced using embedded piles. The results obtained with both models were compared with the data obtained from full-scale loading tests in a case study of a driven pile followed by a micropilote, subjected to compression, tension and shear (case 1), and with the results of an elastoplastic analysis carried out with the well-established integral equation method (case 2). In case 1, the results of the pile subject to compression revealed that the volume pile can reproduce the step produced by a change in the section of the pile, something not possible with an embedded pile. For tension tests or lateral load, the embedded pile reproduces better the displacement measured in the head of the pile or the efforts along the shaft. The conclusions obtained refer mainly to the types of numerical modelling described in the text of the paper and to the programs in which they apply.
2019-07-05T00:00:00ZSeismic capacity and vulnerability assessment considering ageing effects. Case study: 2 Three local Portuguese RC buildings
https://hdl.handle.net/11441/155398
Seismic capacity and vulnerability assessment considering ageing effects. Case study: 2 Three local Portuguese RC buildings
A high percentage of reinforced concrete (RC) buildings in Portugal were designed and
built before the introduction of modern seismic codes. This research aims to assess the
seismic capacity and vulnerability of RC buildings in the city of Lisbon. For that
purpose, nonlinear static procedures have been used and fragility curves have been
developed. These buildings are reaching the end of their nominal life. Therefore,
ageing effects have been taken into account, as well as the presence of smooth rebar.
To do so, a sensitivity analysis has been performed by considering the chlorideinduced
corrosion of the reinforcement steel rebar and the degradation of the concrete
cover. To illustrate the effects of ageing and the procedure adopted for the seismic
fragility assessment of old RC structures, three RC buildings with masonry infills have
been selected as case studies. They were all built between 1960 and 1980, and they
are representative of the current building stock in Lisbon. The seismic capacity of the
buildings has been determined by means of nonlinear static analyses of threedimensional
numerical models. The N2 method and its extended version have been
considered to determine the target displacement. The seismic safety of the buildings
has been estimated in terms of the demand/capacity ratio (DCR) for each vertical
structural element (columns and walls) according to the bending and the shear failures.
Then, a set of fragility curves has been developed for all the buildings’ RC columns
and walls to represent the probability of reaching or exceeding the significant damage
state. Results have shown that the concrete strength degradation has had more
influence than reduction of the rebar diameter in the seismic capacity. When
considering steel corrosion, it has been demonstrated that the corrosion rate has
reduced the capacity more than the time of exposure. It can be concluded that ageing
affects the seismic behaviour of RC structures, increasing the vulnerability of these
buildings.
2020-01-01T00:00:00ZDigital reactivation of territories through geospatial cultural itineraries: the VIDA-HTL web application
https://hdl.handle.net/11441/155318
Digital reactivation of territories through geospatial cultural itineraries: the VIDA-HTL web application
The significant imbalances between human settlements and their surrounding environments, stemming from sector-
specific policies and urban regional planning tools, constitute a primary factor in the resilience and responsiveness
of territories in crisis scenarios. Within this context, the promotion of territorial heritage values emerges
as a crucial means for the reactivation of vulnerable areas. Furthermore, the utilisation of technological resources,
such as Geographic Information Systems (GIS), has proven to be highly effective in managing cultural landscape
areas. This contribution aims to enhance the valorisation of territorial heritage through the geolocation of a system
of architectural and archaeological assets of public interest, and by enabling the flexible design of cultural itineraries
within the framework of slow tourism. For this purpose, a replicable methodology for the construction of a Web‑
GIS application has been proposed. This methodology has been put into practice in the territorial area of the lower
Guadalquivir River in Spain, which encompasses 73 municipalities and one UNESCO World Heritage Site, all interconnected
by rural areas. A four-stage plan has been followed for the construction of the VIDA-HTL web application:
(1) conceptualisation; (2) development; (3) technical verification; and (4) social viability. The fundamental approach
of the web application is based on the comprehensive integration of subsystems related to cultural heritage on one
hand, and to tourist and environmental services on the other. Two main functions for the exploration of cultural assets
and designing cultural routes have been designed, which complement other capabilities implemented in the web
application. As a result of a detailed standardisation process, 981 cultural assets and 43 supplementary data layers
have been georeferenced and included in the web application, with customised itineraries available for planning
within the study area. Additionally, 49 thematic cultural itineraries are proposed. Finally, the web application is complemented
with the development of a collaborative hub, which encourages its use and enhances its capabilities. It
is concluded that digital tools, such as that proposed, foster knowledge and valorisation of territorial cultural heritage,
while contributing to greater local development. In this way, they function as a counterbalance to the development
of metropolises and the global economy, thereby improving levels of regional resilience.
2024-01-01T00:00:00Z