No abstract

This paper describes and discusses the results of designing and implementing a steel formwork for casting and testing concrete slab specimens with different sizes. The formwork saves space, materials and costs due to the different configurations it may adopt, which allow, for instance, casting slabs with different sizes. The formwork avoids purchasing a greater number of formworks of particular dimensions, which increases costs and the space needed for storage. The formwork performance was assessed through the analysis of numerical results (strain and stress) obtained from simulations using finite element software. Performance was also verified during construction and testing of concrete slab specimens, reinforced with welded-wire meshes or steel fibers. The novel steel formwork herein presented and discussed is currently a patent pending in the Colombian Office of Industry and Commerce.

La energía eólica se muestra como una alternativa técnica y económica con posibilidades de ser implementada en zonas en donde por sus necesidades energéticas y características meteorológicas esta tecnología sea posible. Se relacionan a continuación los parámetros básicos a tener en cuenta en el estudio del comportamiento del viento atmosférico en la capa límite, como un proceso aleatorio estacionario y en condiciones de atmósfera neutra. Con base en lo anterior se establece en este trabajo el procedimiento que se debe seguir durante un proceso de simulación del viento atmosférico mediante la determinación de la función de densidad espectral (PSD) que aproxime la intensidad de turbulencia de las fluctuaciones de la velocidad del viento. Haciendo uso del simulador de aerogenerador del laboratorio de Ing. Mecánica de la Universidad de los Andes se programan los perfiles de velocidad del viento medido y del viento simulado, comparándose en cada caso la potencia generada.

<p>Chloride induced corrosion, caused primarily by de-icing salts or salt spray in marine environments, is one of the most common deterioration processes in reinforced concrete. It often causes a localized loss of section, known as pitting, which can lead to a significant reduction of the structure’s service life. In order to predict the impact of this phenomenon on the mechanical properties of the reinforcing bars in concrete a thorough analysis of its characteristics is needed. At present, most of the models found in literature describe uniform corrosion and those that do address localized corrosion focus on a simplified definition of the reduced cross-sectional area of corroded rebars without due attention to physical characteristics and spatial variability. This may be attributed to the limitations of current non-automated and largely heuristic methods used in evaluating the corrosion characteristics on the surface of reinforcement. Automation of the corrosion measurement method would lead to the development of comprehensive corrosion models considering both systematic and random features of the deterioration process. In this paper, experimental results from corroded bars are processed using 3D scanning techniques and characterised using spatial analysis tools, thus preparing the ground for probabilistic corrosion modelling based on random field concepts.</p>

No abstract