Documents published in Scipedia

• Cálculo de las Constantes de Torsión para Vigas de Secciones Transversales Arbitrarias Utilizando Elementos Finitos

  J. Valdes-Vazquez, J. Valdés-Vázquez

  Revista Mexicana de Métodos Numéricos (2023). Vol. 7, 4

  
  

  Abstract

  En el análisis estructural, es esencial que un ingeniero cuente con un profundo conocimiento de las propiedades de una sección transversal, tales como el área, los momentos de inercia y las constantes de torsión. En particular, el cálculo de las constantes de torsión presenta un desafío significativo, ya que, para secciones conocidas, existen fórmulas exactas o aproximadas que facilitan el proceso. Sin embargo, con las actuales tendencias en construcción que incorporan secciones compuestas o de geometría arbitraria, el cálculo de estas constantes se convierte en un reto considerable. Este trabajo se centra, principalmente, en explorar la obtención de las constantes de torsión mediante métodos numéricos, mejorando su precisión en comparación con las propuestas de otros investigadores.

  Abstract
  En el análisis estructural, es esencial que un ingeniero cuente con un profundo conocimiento de las propiedades de una sección transversal, tales como el área, [...]

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• Comparison of axial loads from design live load models and real trucks on existing 3D-truss bridges in Mexico

  A. Hernández-Martínez, A. García-Soto, J. Valdes-Vazquez

  Revista Mexicana de Métodos Numéricos (2023). Vol. 7, 2

  
  

  Abstract

  The load effects to which bridge systems and structural elements are subjected to due to vehicular passage are estimated using live load models contained in bridge design codes. Those live load models are frequently derived for girder bridges subjected to shear forces and bending moments. However, other type of bridges, as truss bridges and others, can be subjected to other forces too, for instance axial loads and other effects. In Mexico, in past decades 3D-truss bridges based on a structural system known as “Tridilosa” were designed and built. The live load models to analyze them were widely used to design girder bridges; moreover, the traffic at the time may differ from more recent trucks and vehicles. This paper investigates the adequacy of live load models from codified design to represent load forces on the referred 3D-truss bridges, as compared to realistic Mexican traffic from WIM (weigh-in-motion) data. The results show that live load models in bridge codes are not necessarily adequate to assess forces in the existing 3D-truss (“Tridilosa”) bridges in Mexico.

  Abstract
  The load effects to which bridge systems and structural elements are subjected to due to vehicular passage are estimated using live load models contained in bridge design [...]

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• Nonlinear finite element analysis of orthotropic and prestressed membrane structures

  J. Valdes-Vazquez, J. Canet, E. Oñate

  Finite Elements in Analysis and Design (2009). Vol. 45 (6-7), pp. 395-405

  
  

  Abstract

  A new methodology for the geometrically nonlinear analysis of orthotropic membrane structures using triangular finite elements is presented. The approach is based on writing the constitutive equations in the principal fiber orientation of the material. A direct consequence of the fiber orientation strategy is the possibility to analyze initially out-of-plane prestressed membrane structures. An algorithm to model wrinkling behavior is also described. Examples of application to a number of membrane structures are presented.

  Abstract
  A new methodology for the geometrically nonlinear analysis of orthotropic membrane structures using triangular finite elements is presented. The approach is based on writing [...]

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• Orthotropic rotation-free basic thin shell triangle

  J. Valdes-Vazquez, E. Oñate

  Computational Mechanics (2009). Vol. 44 (3), pp. 363-375

  
  

  Abstract

  A methodology for the geometrically nonlinear analysis of orthotropic shells using a rotation-free shell triangular element is developed. The method is based on the computation of the strain and stress fields in the principal fiber orientation of the material. Details of the definition of the fiber orientation in a mesh of triangles and of the general formulation of the orthotropic rotation-free element are given. The accuracy of the formulation is demonstrated in examples of application.

  Abstract
  A methodology for the geometrically nonlinear analysis of orthotropic shells using a rotation-free shell triangular element is developed. The method is based on the computation [...]

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• Una formulación acoplada sólido-estructura para el análisis de vigas de concreto postensado

  J. Valdes-Vazquez, C. Andrade-Moreno, A. García-Soto, A. Hernández-Martínez, J. Valdés-Vázquez, F. Luna-Rodríguez

  Revista Mexicana de Métodos Numéricos (2018). Vol. 2, 4

  
  

  Abstract

  Se presenta una formulación numérica en base al método de los elementos finitos para obtener los esfuerzos y desplazamientos de vigas de concreto postensado. La formulación acopla los cables de postensado con la formulación del sólido, considerando al cable como estructura con apoyos intermedios embebidos en el sólido, lo que es una alternativa novedosa y la principal aportación de este trabajo, ya que no sólo es factible de implementarse con elementos finitos como aquí se muestra, sino que es versátil, en el sentido de que cualquier combinación de carga común y condiciones de apoyo puede representarse con el modelo; pero además, el modelo también es de aplicación práctica para el análisis y diseño de trabes de concreto postensado. El método es validado comparándolo con una alternativa reportada en la literatura, y mediante tres ejemplos con cargas diferentes, con los que se muestra que la formulación propuesta da muy buenos resultados. Está alternativa mediante métodos numéricos, puede extenderse a casos más complejos en el futuro, ya que explota la conveniencia de los elementos finitos, que son más precisos y de más amplia aplicación que otros métodos simplificados, comúnmente usados para diseñar vigas de concreto postensado.

  Abstract
  Se presenta una formulación numérica en base al método de los elementos finitos para obtener los esfuerzos y desplazamientos de vigas de concreto postensado. [...]

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• Dynamic Analysis of Hypar Membrane Structures Subjected to Seismic Excitations

  J. Valdes-Vazquez, A. García-Soto, A. Hernández-Martínez

  Rev. int. métodos numér. cálc. diseño ing. (2019). Vol. 35, (1), 11

  
  

  Abstract

  The seismic response of tensile membrane structures (TMS) is investigated. To the authors knowledge, this is the first study on TMSs subjected to a seismic record reported in the literature. A type of membrane structures usually considered as a reference in other works are employed in the present study. The selected hyperbolic-paraboloid fabric structures, also referred as hypar TMSs, are subjected to an earthquake accelerogram from a relatively large earthquake recorded at Norcia, Italy. To obtain the TMSs seismic re- sponse, a finite element formulation reported in a previous study, and which accounts for wrinkling phenomena, orthotropic material modeling, and geometrical nonlinearity, is employed. The analyses are performed in two stages; first for the prestressed case and then the seismic loading is added. It is found that the seismic response of TMSs should not be disregarded by designers beforehand, since important increments in the dynamic response of the displacements produce an incremet of around 9% for stresses. However, a very important increment of around 80% for support reaction forces is computed, when compared with the static case. It is also found that the orientation of the frame-supporting structure has a significant impact on the computed seismic reactions.

  Abstract
  The seismic response of tensile membrane structures (TMS) is investigated. To the authors knowledge, this is the first study on TMSs subjected to a seismic record reported [...]

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