Las estructuras mixtas de hormigón y acero

Calzón, Julio Martínez

doi:10.3989/ic.1966.v19.i182.4193

Cited by 7 publications

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“…Concrete and steel fatigue were not considered, as this ultimate limit state is rarely checked in pedestrian bridges. In addition, the recommendations indicated in the specialized bibliography [43][44][45] were considered.…”

Section: Structural Analysis and Constraintsmentioning

confidence: 99%

Heuristic Techniques for the Design of Steel-Concrete Composite Pedestrian Bridges

et al. 2019

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The objective of this work was to apply heuristic optimization techniques to a steel-concrete composite pedestrian bridge, modeled like a beam on two supports. A program has been developed in Fortran programming language, capable of generating pedestrian bridges, checking them, and evaluating their cost. The following algorithms were implemented: descent local search (DLS), a hybrid simulated annealing with a mutation operator (SAMO2), and a glow-worms swarm optimization (GSO) in two variants. The first one only considers the GSO and the second combines GSO and DLS, applying the DSL heuristic to the best solutions obtained by the GSO. The results were compared according to the lowest cost. The GSO and DLS algorithms combined obtained the best results in terms of cost. Furthermore, a comparison between the CO2 emissions associated with the amount of materials obtained by every heuristic technique and the original design solution were studied. Finally, a parametric study was carried out according to the span length of the pedestrian bridge.

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Section: Structural Analysis and Constraintsmentioning

confidence: 99%

Heuristic Techniques for the Design of Steel-Concrete Composite Pedestrian Bridges

et al. 2019

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“…3 Método de las j J. Martínez Calzón y J. Ortiz Herrera proponen en su libro Construcción Mixta [15] (1978), un método para el análisis diferido de estructuras mixtas, que permite la integración de forma simplificada de la ecuación de Volterra. Este método permite obtener la evolución del estado tensional de las secciones mixtas, simplemente haciendo un cálculo con características homogeneizadas para un tiempo t (en general t = oo) utilizando para el hormigón un módulo de deformación equivalente que viene dado por la expresión: Esto es posible haciendo una hipótesis sobre el tipo de variación con el tiempo de la tensión en el hormigón.…”

Section: Método De Las J 191unclassified

“…O-Asr = yjcrl^,modelo " '^lr,corr i}^) (15) En estas expresiones (Tmodeio representa la desviación típica total del modelo reológico obtenida por comparación de los resultados experimentales con el modelo reológico en cuestión. De esta manera las variables aleatorias J y Er serán la suma de otras dos variables según:…”

Section: Análisis Estadístico Considerando La Correlación Fluencia-re...unclassified

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Comportamiento en servicio del hormigón estructural : Estudio teórico y experimental

Caldentey¹

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The work summed up in this document, must be understood in the framework of a general investigation line, undertaken by the Concrete Department of the Civil Engineering School of Madrid in 1985, with the financial support of the Roads Department of the Ministry of Public Works to three difFerent projects involving laboratory testing.The first of these, which was carried out from 1985 to 1989, consisted in the experimental analysis of the time-dependent behaviour of four simlply supported precast prestressed concrete beams. The results of this project are included in the PhD Thesis of Ramiro Rodríguez [58], supervised by Hugo Corres. The second project was carried out by Hugo Corres and José Romo from 1989 to 1991 and was centered on the study of prestressing losses. For this, 6 concrete columns with a centered prestressing were tested [59].This third project is intended to generalize the previous studies for the case of statically undetermined concrete elements.In the available bibliography, different models for the study of timedependent effects on concrete structures may be found, some of which consider concrete structures built in different phases, both at the sectional level and at the structural level [41,23,44,32,17].However, this type of analysis cannot be easily used by designers, who must evalúate the eífect on their structures of such complex phenomena by using simplified methods, which, sometimes, are not very rigourous. The objective of this work is to deal with time-dependent effects from a practical point of view, trying to compare the results of simplified criteria, used by designers, with those of more complex models, providing an idea of the errors these criteria entail. Another important problem considered is how to improve design without making it more complex.In order to achieve these goals, the problem is seen in a global manner, starting from the time-dependent behaviour of concrete at the fiber level, moving on to the eífects of this behaviour on structures, analysed both experimentally and theoretically, using different levéis of complexity, and, finally, evaluating the eíFects upon such analysis of the uncertainties surrounding the data and the modelling of the problem.This document is divided into five chapters, each of which deals with one of these problems, a summary of the main conclusions reached, and a proposal for future developments which naturally continué the work undertaken.In Chapter I, the time-dependent behaviour of concrete is considered at the fiber level. Using as support a great deal of experimental evidence, the influence of the different parameters, relating to concrete composition, humidity, temperature and specimen dimensions, on creep and shrinkage of concrete is observed. This behaviour is then explained on the basis of the physical mechanisms involved, which have been identified by different 26 I. MODELOS REOLOGICOS. MICROMECANICA

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“…(Tomada de (39)) MARTÍNEZ CALZÓN y ORTIZ HERRERA (40) recoge una visión general de diferentes tipos de presolicitaciones en estructuras mixtas. Advierten que, con el planteamiento teórico de esta tipología estructural según el cual la cabeza de hormigón no resiste, por sí misma, carga alguna 1 , es necesario complementar todo análisis tensional asociado a estas presolicitaciones con el análisis en agotamiento, pues en este último (…) la influencia de la presolicitación será eficaz en cuanto a que incorpore material resistente apropiado, y prácticamente ineficaz si se refiere a operaciones mecánicas constructivas de predeformación o cambio de secuencia del acoplamiento de los materiales.…”

Section: Figura 24-6unclassified

Refuerzo de vigas de hormigón armado mediante la aplicación de fuerzas exteriores introducidas por predeformación de perfiles metálicos

Escribano¹

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One technique for strengthening flexural members in general, and reinforced concrete beams and slabs in particular, entails caulking the underside of these members with steel shapes. This sort of strengthening is often designed from a passive approach; i.e., until the load is increased, the shapes are either not loaded or are only slightly loaded to some unquantified extent by caulking with steel shims.

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Las estructuras mixtas de hormigón y acero

Cited by 7 publications

References 0 publications

Heuristic Techniques for the Design of Steel-Concrete Composite Pedestrian Bridges

Heuristic Techniques for the Design of Steel-Concrete Composite Pedestrian Bridges

Comportamiento en servicio del hormigón estructural : Estudio teórico y experimental

Refuerzo de vigas de hormigón armado mediante la aplicación de fuerzas exteriores introducidas por predeformación de perfiles metálicos

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