Documents published in 2018 : Scipedia

Analysis of post-tensioned structures by means of a constitutive serial-parallel rule of mixtures
S. Jiménez, L. Barbu, S. Oller

Monograph CIMNE (2018). M178

Abstract
The main objective of this thesis is to present a novel methodology for the analysis of post-tensioned concrete structures, based on the potential offered by the use of the Serial-Parallel Rule of Mixtures when modelling composite materials. The advantages of this methodology are studied in comparison to the available approaches, i.e. the formulation proposed by the standards used in the design of structures and the mechanism used in numerical simulation based on the finite element method (FEM). The Serial-Parallel Rule of Mixtures allows the modelization of each component material in depth, working as a constitutive model manager in order to simulate the composite material being studied. The prestressed concrete is modelled as a composite material with long fibres where the fibre orientation is defined by the steel tendon direction. Therefore, the most suitable constitutive model can be used in each case. In the present thesis this is: for the matrix - concrete an isotropic damage model and for the fibre - steel a viscoelasticity model, achieving an extraordinary accuracy in the micro-scale. The analysis is based on the FEM, which combined with the Serial-Parallel Rule of Mixtures theory allows the study of large-scale structures, taking into account the specific geometric requirements of the construction. Three application examples are included which are used for validating the methodology and the potential of this approach. The first two cases are two isostatic beams that allow the comparison with the results obtained through the study using analytical methods. Finally, the third case shows the results obtained recently for the analysis of a Benchmark, in which the behaviour of a mock-up of a reactor containment building has been studied.
Abstract
The main objective of this thesis is to present a novel methodology for the analysis of post-tensioned concrete structures, based on the potential offered by the use of the [...]
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La simplificación en ingeniería, ventajas e inconvenientes.
F. Zarate, J. Cuellar, A. Regalado

Revista Mexicana de Métodos Numéricos (2018). Vol. 2, 1

Abstract
Siempre que se realiza una simplificación, se suele cometer un error asociado, la capacidad del ingeniero en cuantificar o poder compensar dicho error con coeficientes de seguridad u otros mecanismos permite adoptar dichas simplificaciones en la mayoría de las situaciones. Sin embargo, no en todos los casos es posible aplicar dichas simplificaciones en los cálculos. Los procedimientos y programas de cálculo son muy diferentes en ambos casos. El presente trabajo muestra dos ejemplos de cálculo numérico asociado a una misma obra. Mientras que el primero tiene como finalidad el dimensionamiento y verificación de la capacidad estructural, el segundo pone de manifiesto la necesidad de considerar en detalle aspectos que han sido obviados o simplificados a fin de dar una respuesta adecuada. Los códigos usados son muy distintos, en el primer caso, es posible aplicar códigos comerciales, mientras que en el segundo es necesario usar programas diseñados para la investigación.
Abstract
Siempre que se realiza una simplificación, se suele cometer un error asociado, la capacidad del ingeniero en cuantificar o poder compensar dicho error con coeficientes [...]
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Analysis of time dependent problems using exponential basis functions
B. Movahedian, B. Boroomand

(2011). Research Report, Nº PI364

Abstract
In this research we present a method based on using Exponential Basis Functions (EBFs) to solve a class of time dependent engineering problems. The solution is first approximated by a summation of EBFs satisfying the differential equation and then completed by satisfying the time dependent boundary conditions as well as the initial conditions through a collocation method. This can be performed by considering two approaches. In the first one the solution is split into three parts, i.e. a homogeneous solution obtained by homogeneous boundary conditions, a homogeneous solution obtained by non-homogeneous solution and finally a particular solution induced by source terms. In the second approach the solution is split into two parts, i.e. a homogeneous solution and a particular solution induced by source terms. The two approaches are then employed to construct a time marching algorithm for the solution of problems over a long period of time. We shall present the details of the application of the two approaches introduced to some mathematical and engineering problems. The details of the time marching algorithm proposed are explained. Several problems are solved to show the capabilities of the approaches used. Some benchmark problems are also devised and solved for further studies. It is shown that the one of the introduced approaches is capable of solving a class of problems with moving boundaries.
Abstract
In this research we present a method based on using Exponential Basis Functions (EBFs) to solve a class of time dependent engineering problems. The solution is first approximated [...]
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Exponential basis functions in solution of incompressible fluid problems with moving free surfaces
S. Zandi, B. Boroomand, S. Soghrati

(2011). Research Report, Nº PI363

Abstract
In this report, a new simple meshless method is presented for the solution of incompressible inviscid fluid flow problems with moving boundaries. A Lagrangian formulation established on pressure, as a potential equation, is employed. In this method, the approximate solution is expressed by a linear combination of exponential basis functions (EBFs), with complex-valued exponents, satisfying the governing equation. Constant coefficients of the solution series are evaluated through point collocation on the domain boundaries via a complex discrete transformation technique. The numerical solution is performed in a time marching approach using an implicit algorithm. In each time step, the governing equation is solved at the beginning and the end of the step, with the aid of an intermediate geometry. The use of EBFs helps to find boundary velocities with high accuracy leading to a precise geometry updating. The developed Lagrangian meshless algorithm is applied to variety of linear and nonlinear benchmark problems. Non-linear sloshing fluids in rigid rectangular two-dimensional basins are particularly addressed.
Abstract
In this report, a new simple meshless method is presented for the solution of incompressible inviscid fluid flow problems with moving boundaries. A Lagrangian formulation [...]
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Paralelización del código Stampack v7.10
W. Castelló, F. Flores

(2011). Research Report, Nº PI362

Abstract
El objetivo principal del presente informe es mostrar las mejoras en la performance del código Stampack, cuando se lo emplea en conjunto con OpenMP en máquinas del tipo multi-núcleo (ej.: Intel Core2 Duo, Intel Core2 Quad, etc) o multi-thread (ej.: Intel Core i3, i5, i7, etc). Esta última tecnología en los procesadores (multi-thread) permite aumentar de manera importante la potencia de cálculo, dado que además de contar con más de un procesador, permite aumentar los hilos (threads) de tareas simultaneas de cada núcleo. Por ejemplo un procesador Intel Core i3, puede tener dos procesadores y realizar dos tareas simultaneas por cada procesador, lo cual es equivalente a tener una máquina con cuatro procesadores. En el caso del procesador Intel Core i7 empleado en este trabajo cuenta con cuatro núcleos y la posibilidad de realizar dos tareas simultaneas por núcleo, lo cual equivale a tener ocho procesadores. La paralelización del software Stampack se ha realizado siguiendo la idea básica de modificar o intervenir mínimamente los archivos fuente originales de la versión serial. Bajo estas condiciones, se ha realizado un análisis de tiempos para detectar zonas del código que representen un importante porcentaje del tiempo total de cálculo. Para finalizar se debe destacar que el software paralelizado debe funcionar también de manera correcta cuando es ejecutado en ordenadores con un solo procesador, de manera que la versión paralela debe ser compatible en su totalidad con la versión serial original del código Stampack.
Abstract
El objetivo principal del presente informe es mostrar las mejoras en la performance del código Stampack, cuando se lo emplea en conjunto con OpenMP en máquinas [...]
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Simplificación de mallas de triángulos
M. Pasenau, C. Andújar

(2011). Research Report, Nº PI361

Abstract
El objetivo principal del proyecto de fin de carrera es el análisis, diseño, implementación y prueba de un algoritmo que permita simplificar rápidamente una malla de triángulos muy densa, tratando de minimizar tanto el error geométrico como el error de atributos definidos en la superficie, para que el usuario pueda interaccionar con ella en plataformas modestas.
Abstract
El objetivo principal del proyecto de fin de carrera es el análisis, diseño, implementación y prueba de un algoritmo que permita simplificar rápidamente [...]
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Possibilities of the particle finite element method for fluid-soil-structure interaction problems
E. Oñate, M. Celigueta, S. Idelsohn, F. Salazar, B. Suarez

(2011). Research Report, Nº PI357

Abstract
We present some developments in the Particle Finite Element Method (PFEM) for analysis of complex coupled problems in mechanics involving fluid-soil-structure interaction (FSSI). The PFEM uses an updated Lagrangian description to model the motion of nodes (particles) in both the fluid and the solid domains (the later including soil/rock and structures). A mesh connects the particles (nodes) defining the discretized domain where the governing equations for each of the constituent materials are solved as in the standard FEM. The stabilization for dealing with an incompressibility continuum is introduced via the finite calculus (FIC) method. An incremental iterative scheme for the solution of the non linear transient coupled FSSI problem is described. The procedure to model frictional contact conditions and material erosion at fluid-solid and solid-solid interfaces is described. We present several examples of application of the PFEM to solve FSSI problems such as the motion of rocks by water streams, the erosion of a river bed adjacent to a bridge foundation, the stability of breakwaters and constructions sea waves and the study of landslides.
Abstract
We present some developments in the Particle Finite Element Method (PFEM) for analysis of complex coupled problems in mechanics involving fluid-soil-structure interaction [...]
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El ciclo de las ideas en la I+D+I
E. Oñate

(2011). Research Report, Nº PI354

Abstract
Cuando se habla de la investigación, el desarrollo tecnológico y la innovación (I+D+I en siglas, que yo escribo todas en mayúsculas [1]) es frecuente confundir fines, medios y responsabilidades. La última moda parece que es exigir que los grupos que investigan en Universidades y Centros de I+D, sean "rentables". Es decir, se pretende que su investigación se financie con créditos públicos, que los resultados de la misma se implementen en el mercado rápidamente y que los beneficios de su comercialización sirvan para devolver los créditos y para refinanciar esos grupos. También parece que se echa de menos que las empresas investiguen más, es decir, que inviertan recursos en descubrir nuevos conocimientos. El límite caricaturesco de esas aspiraciones sería pretender que las empresas produjeran premios Nobel y que un grupo universitario estuviera entre los 10 primeros puestos en el ranking de la actividad económica de un país. Ciertamente, esto no es imposible, pero es altamente improbable. Lo contrario desgraciadamente es más frecuente. Es decir, que los investigadores universitarios en su afán por la supervivencia económica de sus grupos, descuiden sus tareas investigadoras y que las empresas, confundiendo lo que es un Departamento Técnico o de Proyectos, con un Departamento de Innovación, se consideren autosuficientes y menosprecien u obvien el contacto con el mundo de la I+D real.
Abstract
Cuando se habla de la investigación, el desarrollo tecnológico y la innovación (I+D+I en siglas, que yo escribo todas en mayúsculas [1]) es frecuente [...]
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On the use of exponential basis functions in the analysis of shear deformable laminated plates
M. Shahbazi, B. Boroomand, S. Soghrati

(2011). Research Report, Nº PI353

Abstract
In this report, we introduce a meshfree approach for static analysis of isotropic/orthotropic crossply laminated plates with symmetric/non-symmetric layers. Classical, first and third order shear deformation plate theories are employed to perform the analyses. In this method, the solution is first split into homogenous and particular parts and then the homogenous part is approximated by the summation of an appropriately selected set of exponential basis functions (EBFs) with unknown coefficients. In the homogenous solution the EBFs are restricted to satisfy the governing differential equation. The particular solution is derived using a similar approach and another series of EBFs. The imposition of the boundary conditions and determination of the unknown coefficients are performed by a collocation method through a discrete transformation technique. The solution method allows us to obtain semi-analytical solution of plate problems with various shapes and boundary conditions. The solutions of several benchmark plate problems with various geometries are presented to validate the results.
Abstract
In this report, we introduce a meshfree approach for static analysis of isotropic/orthotropic crossply laminated plates with symmetric/non-symmetric layers. Classical, first [...]
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Methodologies for tracking of load extremes and error estimation using probabilistic techniques
R. Flores, E. Ortega, R. López

(2012). Research Report, Nº PI375

Abstract
This work, conducted at CIMNE under ALEF project task 1.2.3, presents an investigation about the potential capabilities of neural networks to assist simulation campaigns. The discrete gust response of an aircraft has been chosen as a typical problem in which the determination of the critical loads requires exploring a large parameter space. A very simple model has been used to compute the aerodynamic loads. This allows creating a large database while at the same time retaining some of the fundamental properties of the problem. Using this comprehensive dataset the effects of network structure, training method and sampling strategy on the level of approximation over the complete domain have been investigated. The capabilities of the neural network to predict the peak load as well as the critical values of the design parameters have also been assessed. The applicability of neural networks to the combination of multi-fidelity results is also explored.
Abstract
This work, conducted at CIMNE under ALEF project task 1.2.3, presents an investigation about the potential capabilities of neural networks to assist simulation campaigns. [...]
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A four-noded quadrilateral element for composite laminated plates/shell using the refined zigzag theory
A. Eijo, E. Oñate, S. Oller

(2012). Research Report, Nº PI378

Abstract
A new bilinear 4-noded quadrilateral element (called QLRZ) for the analysis of composite laminated and sandwich plates/shells based on the refined zigzag theory (RZT) proposed by Tessler et al. [1] is presented. The element has seven kinematic variables per node. Shear locking is avoided by introducing an assumed linear shear strain field. The performance of the element is studied in several examples where the reference solution is the 3D finite element analysis using 20-noded hexahedral elements. Finally, the capability for capturing delamination effects is analyzed.
Abstract
A new bilinear 4-noded quadrilateral element (called QLRZ) for the analysis of composite laminated and sandwich plates/shells based on the refined zigzag theory (RZT) proposed [...]
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Puente Tensairity para pasarela peatonal en el PMT-UPC de Castelldefels (737-PRO-CA-5385)
C. Estruch, B. Suárez, J. Marcipar

(2012). Research Report, Nº PI380

Abstract
Actualmente el espacio formado por el “Parc Mediterrani de la Tecnologia” y el Campus Universitario de la Universitat Politècnica de Catalunya (PMT-UPC) de Castelldefels está en expansión. Es por ello que se está pensando en la construcción de dos pasarelas peatonales para cruzar la laguna de laminación de la “Olla del Rei”, conectando de esta forma el PMT-UPC con el paseo del Pitort. Dado que el PMT-UPC pretende ser un referente ambiental y tecnológico, se plantea como alternativa óptima la construcción de una pasarela peatonal ligera diseñada mediante una novedosa tecnología neumática conocida y patentada con el nombre de Tensairity®. Las estructuras ligeras son un reto para el ingeniero estructural y un importante avance hacia una arquitectura sostenible. Tensairity® es un concepto que hace referencia a estructuras neumáticas ligeras basadas en una sutil interacción entre cables, elementos de compresión, membranas y aire a baja presión. En Tensairity®, compresión y tracción están físicamente separados por una membrana de tejido hinchada a baja presión, el fin de la cual es, por un lado pretensar el elemento de tracción, y por el otro estabilizar el elemento de compresión frente al pandeo. Esto permite llevar al material hasta su límite plástico, tanto para tracción como para compresión, dando como resultado vigas que pueden ser varios órdenes de magnitud más ligeras que las vigas metálicas convencionales, manteniendo siempre su misma capacidad de carga. Aplicaciones ideales para esta tecnología son cerchas, estructuras con grandes luces, estructuras temporales, pasarelas peatonales o incluso estructuras de despliegue rápido para casos de emergencia, entre otras. La pasarela peatonal objeto de este proyecto está compuesta por dos partes bien diferenciadas, una pasarela Tensairity® que cruza la laguna de laminación y dos estructuras de madera a modo de embarcaderos, una a cada lado de la pasarela y donde ésta se apoya hasta alcanzar los caminos que bordean el trazado de la laguna. La pasarela Tensairity® está formada por dos vigas Tensairity® compuestas cada una de ellas por un tubo hinchable de PVC en cuya parte superior se apoya una viga de madera a modo de elemento de compresión y en su parte inferior una cinta de carga a modo de elemento de tracción. Sobre estas dos vigas se sustenta la superestructura de la pasarela formada por vigas transversales de madera sobre las que se apoya el tablero y las barandillas, también de madera. Las estructuras de apoyo se construyen igualmente en madera, con una tipología estructural similar al de la pasarela y mediante el uso de pilotes que recuerda en cierta manera los embarcaderos presentes en los ríos, de forma que la estructura completa esté integrada en el entorno.
Abstract
Actualmente el espacio formado por el “Parc Mediterrani de la Tecnologia” y el Campus Universitario de la Universitat Politècnica de Catalunya (PMT-UPC) [...]
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Continuum modelling using the discrete element method. theory and implementation in an object-oriented software platform
M. Santasusana, E. Oñate

(2012). Research Report, Nº PI381

Abstract
The Discrete Element Method is a relatively new technique that has nowadays and intense research in the field of numerical methods. In its first conception, the method was designed for simulations of dynamic system of particles where each element is considered to be an independent and non-deformable entity that interacts with other particles by the laws of the contact mechanics and moves following the second Newton’s law. This first approach for the DEM has obtained excellent results for granular media simulations or another discontinuouslike case. The existing challenge nowadays for the DEM is to be able to simulate the behaviour on a continuous media discretized by a mesh of particles ruled by the equations of the DEM. Although there exist more adequate methods to solve the continuous problem as they are the different variants of the Finite Element Method, the DEM is expected to have a better behaviour when the failure of the media occurs; in terms of tracking the evolution of the fracture locally between the elements of the discretization and also the post-fractural behaviour of the material. Nowadays, there are several DEM codes that try to solve this problem although there is no one which can assure an accurate solution applicable universally to any case. The objective of the present work is to develop calculation software for the Discrete Element Method included in the platform for numerical methods KRATOS, which is developed in CIMNE. One of the goals of the so-called DEM-Application is to be able to reproduce a wide set of engineering problems; not only the discrete ones such as the excavation or agroalimentary applications but also to reproduce the continuous media, simulating compression test for concrete or asphalt samples for instance. In addition it is desired that the application permits the coupling with another methods, particularly the Finite Element Method. In order to do this, the present work includes the study of all the advances and ideas that, globally in the numerical method field and particularly in CIMNE, have been discussed to give other approaches and to keep improving and developing the to the Discrete Element Method.
Abstract
The Discrete Element Method is a relatively new technique that has nowadays and intense research in the field of numerical methods. In its first conception, the method was [...]
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Proper generalized decomposition for parameterized Helmholtz problems in heterogeneous and unbounded domains: Application to harbor agitation
D. Modesto, S. Zlotnik, A. Huerta

(2013). Research Report, Nº PI401

Abstract
Solving the Helmholtz equation for a large number of input data in an heterogeneous media and unbounded domain still represents a challenge. This is due to the particular nature of the Helmholtz operator and the sensibility of the solution to small variations of the data. Here a reduced order model is used to determine the scattered solution everywhere in the domain for any incoming wave direction and frequency. Moreover, this is applied to a real engineering problem: water agitation inside real harbors for low to mid-high frequencies. The Proper Generalized Decomposition (PGD) model reduction approach is used to obtain a separable representation of the solution at any point and for any incoming wave direction and frequency. Here, its applicability to such a problem is discussed and demonstrated. More precisely, the separability of the operator is addressed taking into account both the non-constant coe
Abstract
Solving the Helmholtz equation for a large number of input data in an heterogeneous media and unbounded domain still represents a challenge. This is due to the particular [...]
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Desarrollo y aplicación de un modelo de elementos finitos para cálculo de vigas con materiales compuestos laminados basado en la teoría de Timoshenko
A. Llanos, E. Oñate, F. Zárate

(2013). Research Report, Nº PI398

Abstract
Actualmente existen programas de MAT-fem para calcular vigas de material homogéneo, según la teoría de Euler-Bernoulli o de Timoshenko. El objetivo de la presente tesina es conseguir un nuevo programa capaz de calcular vigas de materiales compuestos con la teoría de Timoshenko. En el capítulo 1, se introducen los materiales compuestos describiendo las ventajas y aplicaciones que tienen hoy en día en el ámbito de la Ingeniería Cívil. En el capítulo 2 y 3 se expone la teoría de las vigas planas laminadas y, en particular, de las vigas compuestas de Timoshenko. El capítulo 4 explica cómo se ha llevado a cabo la implementación numérica y da paso al capítulo 5, en el que se exponen varios ejemplos. Por último, en el capítulo 6, se exponen las conclusiones que se extraen del trabajo realizado y de los resultados obtenidos. Finalmente se presentan los anejos. Primero, en el anejo 1, se muestra un ejemplo real de refuerzo de viga mediante materiales compuestos. En el segundo anejo se presentan más ejemplos de los expuestos en el quinto capítulo y, por último, se termina la tesina con el anejo 3, que presenta los distintos archivos de programación utilizados para el cálculo de vigas compuestas de Timoshenko.
Abstract
Actualmente existen programas de MAT-fem para calcular vigas de material homogéneo, según la teoría de Euler-Bernoulli o de Timoshenko. El objetivo de [...]
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Numerically stable formulas for a material point based explicit exponential integrator
P. Nadukandi

(2014). Research Report, Nº PI408

Abstract
We present numerically stable formulas for the analytical solution in the closed form of the so-called X-IVAS scheme in 3D. The X-IVAS scheme is a material point based explicit exponential integrator. An intermediate step in the X-IVAS scheme is the solution of tangent curves for piecewise linear vector fields defined on simplicial meshes. This is what we refer to as particle tracing of streamlines and independent formulas for the same can be easily distilled from the ones presented for the X-IVAS scheme. The formulas involve functions of matrices which are defined using the corresponding Newton interpolating polynomial. The evaluation of these formulas is stable, i.e. a certain number of significant digits in the computed values are guaranteed to be exact. Using the double-precision floating-point arithmetic specified by the IEEE 754 standard, we obtain at least 10 significant decimal digits in the worst case scenarios. These scenarios involve fourth-order divided differences of the exponential function. Additionally, an optimal series approximation of divided differences is presented which is an essential part of the exposition.
Abstract
We present numerically stable formulas for the analytical solution in the closed form of the so-called X-IVAS scheme in 3D. The X-IVAS scheme is a material point based [...]
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PARACHUTES: A computer program for calculating ram-air parachutes. Theory document
E. Ortega, R. Flores

(2016). Research Report, Nº PI415

Abstract
PARACHUTES is a computer program developed at the International Center for Numerical Methods in Engineering (CIMNE) for the simulation of ram-air (gliding) parachute systems. The solution methodology in PARACHUTES is based on two unsteady calculation modules which work in a coupled manner. The aerodynamics of the gliding parachute is solved by a low-order panel method and a finite-element technique is used for the structure. The latter allows modelling the suspension lines, textile fabric and suspended payloads of a typical parachute system by means of cable, membrane and solid linear elements. For specified flight conditions, the simulation program solves the fluid-structural problem governing the behavior of arbitrary parachute-payload configurations and also allows analyzing user-defined maneuvers. This document describes the theoretical formulation and the numerical procedures adopted in PARACHUTES.
Abstract
PARACHUTES is a computer program developed at the International Center for Numerical Methods in Engineering (CIMNE) for the simulation of ram-air (gliding) parachute systems. The [...]
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Analysis of Linear Systems Assisted with Scilab: An Approach from Electrical Engineering (2015 Review)
E. Brea

Gaceta Técnica (2018). Vol. 15, 13

Abstract
The analysis of the linear systems as well as of the signals that interact with the different elements of the system and the environment that surrounds it, requires a clear knowledge of the mathematical analysis and especially of what is known as operational calculation, as of the operational calculation it is possible, in some cases, to facilitate the search for the solutions of the problems of analysis that are raised in the investigation of the systems represented by mathematical models. Both the mathematical models that represent the systems and the signals can be defined in terms of continuous or discrete variables, for which each of these points of view requires its corresponding model, and the determination of its solution to the problem will be based on the domain over which the model is represented, whether continuous or discrete, as well as the concepts used in the spectral domain. The author assumes that the reader has a clear knowledge of Laplace, Fourier and Z transform, which are used as alternative tools for the analysis of problems in the domain where the mathematical models are described. On the other hand, brief explanations of some differential equation solving methods are presented in this book, which represent the relationships among the variables of the dynamic system defined in the continuous domain that is being studied. The purpose of introducing differential equations is to induce the method of solving difference equations, which are used as mathematical models of dynamic systems seen from a discrete domain perspective. It is important to note that the scope of this work does not include the analysis of linear systems from the stochastic perspective, because this approach requires clear knowledge of the probabilities and stochastic processes, and that this material It should form the textbook of the undergraduate course of Analysis of Linear Systems of the School of Electrical Engineering of the Central University of Venezuela, and this course studies the systems from the deterministic point of view. It should be noted that the author has used, in a very careful way, a notation that allows to discriminate clearly when the mathematical models are referred to the continuous or discrete domain. Moreover, the author makes a clear difference, in the case of the signals defined in the discrete domain, between what a function in the discrete domain means and its corresponding sequence of samples, both of which are used for the representation of the signals in the domain of discrete domain. In addition, the author has tried as far as possible to refer to the domain, without this being limited to the domain in continuous or discrete time, because in the opinion of the author, the concepts, methods and theoretical bases should not refer exclusively to the domain of time, but to any domain, thus leaving the possibility of generalizing the application of what is presented in the work, although in the area of Electrical Engineering it is very common to see the models and signals defined in the domain of time and frequency. It is appropriate to establish that throughout the work, the signals studied and their use in the analysis of the various systems, both in the continuous and discrete domain, are considered real. That is, they are signals that represent measures in the set of real numbers, or in mathematical terms are signals represented by functions whose ranges correspond to the set of real numbers. In addition, it must be taken into account that the signals are modeled by functions defined in the domain of real or integer numbers, depending on whether the signals represent measurements in the continuous or discrete domain, respectively.
Abstract
The analysis of the linear systems as well as of the signals that interact with the different elements of the system and the environment that surrounds it, requires a clear [...]
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Estudio de la influencia de las irregularidades en planta en la respuesta sísmica de una estructura de concreto armado
L. Pérez Peña, G. Doz

International Journal of Natural Disasters, Accidents and Civil Infrastructure (2018). Vol. 18, (2), 1

Abstract
The changes in the geometry of the structures are called irregularities and are divided into two types: plant and height irregularities, the latter being widely investigated. In this sense, the objective of the present work is to study in detail the influence of the plant irregularities in the seismic resistance of a reinforced concrete structure, to quantify and locate vulnerable zones in the structure. The proposed study is developed numerically using ETABS software Nonlinear v9.7.2 and MATLAB R2009b. The results showed that plant irregularities as they are placed in the structure, this is losing its bearing capacity and therefore its ability to withstand the lateral loads.
Abstract
The changes in the geometry of the structures are called irregularities and are divided into two types: plant and height irregularities, the latter being widely investigated. [...]
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Development and programming of sismic resistant types BFP and RBS connections according to ANSI/AISC 358-16
G. Pannillo, M. Chacón, H. Riera

Gaceta Técnica (2018). Vol. 19 (2), 12

Abstract
Steel connections are a fundamental part in the design and construction process of metal structures. Making this connections design becomes an extensive mathematical procedure, which would generate delays manually due to the number of iterations necessary to obtain an adequate result. There are commercial programs that perform these procedures in an automated way, but their licenses tend to be very expensive, and emphasizing the above, this work has the purpose of creating a free and easy to use software for the design of BFP and RBS connections according to the guidelines established by the ANSI / AISC standard 358-2016. In addition, at the same time incorporate an additional tool for the teaching of matters related to connections in steel structures. The software is accompanied by a user manual that describes step by step some common examples of calculation, which can be used to teach the use of software. The results obtained by the program were compared with exercises developed by other authors, reflecting quite low percentages of difference and with them the acceptance of the results obtained with the program.
Abstract
Steel connections are a fundamental part in the design and construction process of metal structures. Making this connections design becomes an extensive mathematical procedure, [...]
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CIMNE workshop on Scipedia
J. García-Espinosa

Presentations Repository of Scipedia

Abstract
Scipedia (https://www.scipedia.com) is an innovative Open Science and Research Publishing Platform. Scipedia aims to connect researchers and professionals in science and technology and facilitate the sharing of knowledge, expertise and the outcome of their work. Scipedia.com was born to offer a complete solution for open science, and essentially integrates a collaborative social network for scientists with online editorial and document and data management tools. CIMNE has chosen Scipedia as the open publishing platform for its collections of monographs, articles and preprints, and technical and research reports (see https://www.scipedia.com/institution/cimne.upc.edu). The content of these collections will be compiled from the personal repositories in Scipedia of all CIMNE researchers. The objective of the workshop is to resolve the main doubts that may arise in the use of the platform, and specifically in the creation and management of document collections.
Abstract
Scipedia (https://www.scipedia.com) is an innovative Open Science and Research Publishing Platform. Scipedia aims to connect researchers and professionals in science [...]
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Inter institutional agreement Construction Camera of the Lara state school of civil engineering of UCLA
R. Arias

Gaceta Técnica (2018). Vol. 19 (2), 6

Abstract
The Construction Camera of the Lara State in Venezuela has been encouraging courses through the agreement established with the School of Civil Engineering of the Centroccidental University Lisandro Alvarado, with the purpose of updating and maintaining a system of continuous training of its members in the construction area. It has specialized chairs taught at higher levels within the civil engineering career itself, as is the subject 'Construction Management' to specific courses in the structural area. Likewise, the Internship Unit is supported by locating students who need to complete professional internships in companies affiliated with the Camera; including consultancies in degree works from the civil engineering area.
Abstract
The Construction Camera of the Lara State in Venezuela has been encouraging courses through the agreement established with the School of Civil Engineering of the Centroccidental [...]
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Road accidents in Mexico and its relationship with daylight saving time
L. Vázquez, D. Aguirre, M. Demmler

Gaceta Técnica (2018). Vol. 19 (2), 7

Abstract
The objective proposed in this work was to find out if there is a relationship between the beginning of summer time in Mexico and the number of road accidents, since the entrance of such schedule causes fatigue, which is reported as a cause of accidents. The permutations test was used and there was no evidence of an increase in accidents associated with the entry of summer time. The limitations of the study are, on the one hand, the lack of accident records prior to the implementation of summer time and, on the other, not having controlled the time of occurrence of the accidents analyzed; in future cases it is recommended to control this last variable. Summer time in Mexico was implemented since 1996 and its effects on road traffic accidents had not yet been studied; the originality of the present study lies in studying such effects. The findings suggest that vehicular driving with natural light provides greater safety even when the driver is fatigued.
Abstract
The objective proposed in this work was to find out if there is a relationship between the beginning of summer time in Mexico and the number of road accidents, since the entrance [...]
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Mechanical physical study of concrete substitutes with silica powder exposed in simulated aggressive environment
A. Giménez, M. Olavarrieta, L. Escalona, H. Gallegos

Gaceta Técnica (2018). Vol. 19 (2), 8

Abstract
The present research resulted in a standardized laboratory test for the evaluation of properties in a simulated exposure environment by immersion in 3% NaCl solution. The physical and mechanical evaluation was performed on reinforced cylindrical specimens of 30 cm high and 15 cm in diameter, made of concrete with partial replacement of the cement by dose silica in 10% and 15% water cement ratio of 0,45 and 0,65 and design strength of 250 Kgf/cm². Settlement tests, porosity, capillary absorption and mechanical resistance were performed In a period of 5 months, the influence of the substitutions of silica dust in the concrete mixtures with respect to the standard mixtures was analyzed, obtaining an increase in the mechanical resistance with respect to the design, in the ratio a/c 0,45, for the a/c ratio 0,65 reached acceptable values for the substituted mixtures with respect to the mechanical strength compared with the design, as for the porosity and capillary absorption tests were not satisfactory for any relation to a/c probably due to lack of curing prior to exposure.
Abstract
The present research resulted in a standardized laboratory test for the evaluation of properties in a simulated exposure environment by immersion in 3% NaCl solution. The [...]
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Numerical simulation of the structural behavior of tubular profiles submitted to ultra-low cycles fatigue
L. Lopez, R. Picón, M. Marante

Gaceta Técnica (2018). Vol. 19 (2), 9

Abstract
In the present work of investigation the numerical behavior of structural profiles of steel of thin wall is studied, of Venezuelan national production Conduven ECO, of square cross section, constructed in the form of beam type cantilever, under the effects of Fatigue of UltraLow Cycling. Experimental tests were carried out where histories of cyclic displacements were applied, with very low speed and acting in a range that goes from the yielding effort to the last effort of the element, obtaining a degradation of the resistant capacity of the profiles, these experimental results were compared with the numerical simulations made through a commercial program of finite elements, obtaining satisfactory results.
Abstract
In the present work of investigation the numerical behavior of structural profiles of steel of thin wall is studied, of Venezuelan national production Conduven ECO, of square [...]
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Effect of exposure time to fire in flexural strength of reinforced concrete beams
M. Aguirre, G. Aguirre

Gaceta Técnica (2018). Vol. 19 (2), 10

Abstract
This paper discusses the flexural strength of reinforced concrete beams of square cross section, exposed to fire during different times. After being exposed to fire the beams were left to cool at room temperature for 24 hours, the changes produced by this phenomenon were evaluated by observation. The temperatures reached oscillated between 750 °C and 1050 °C. Through the ASTM C78 test it was determined that the flexural strength decreases drastically as the temperature and exposure time of the beams increases, showing different signs of degradation ranging from a slight calcination and change of coloration to the loss of section of the element. This research showed that the flexural strength decreased by more than 90% with respect to the beams not exposed to fire, this result was obtained when a temperature of 1050 °C was reached at 180 minutes of exposure to fire.
Abstract
This paper discusses the flexural strength of reinforced concrete beams of square cross section, exposed to fire during different times. After being exposed to fire the beams [...]
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Data-MSCA-IF: Sensitive clays
X. Zhang

Papers Repository of the International Centre for Numerical Methods in Engineering (CIMNE) (2018). 6

Abstract
Properties of Norwegian clays, Canadian clays and offshore clays
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Data-MSCA-IF: Collapse Velocity
X. Zhang

Papers Repository of the International Centre for Numerical Methods in Engineering (CIMNE) (2018). 7

Abstract
Variations of horizontal and vertical velocities of retrogressive landslides
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Particle finite element modelling of retrogressive slope failure in sensitive clays
X. Zhang, D. Sloan

15th IACMAG (2017). paper no 868

Abstract
In this paper, the slope failure in sensitive clays is studied numerically using the particle finite element method which is a novel approach capable of tackling extreme deformation problems. The sensitive clay is described using an elastoviscoplastic model with strain softening. This model can be considered a mixture of the Tresca model with strain softening and the classical Bingham model. The former is used to capture the solid-like behaviour, for example when the clay is intact, whereas the latter is to describe the semi-fluid behaviour of the fully remolded clay. The complete process of the collapse of a sensitive clay deposit is captured successfully and the widely-observed retrogressive failure mode is reproduced. The mechanism behind the failure is also discovered.
Abstract
In this paper, the slope failure in sensitive clays is studied numerically using the particle finite element method which is a novel approach capable of tackling extreme deformation [...]
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Advances in the Simulation of Ship Navigation in Brash Ice
J. García-Espinosa, B. Servan Camas, J. Colom Cobb, E. Oñate

13th World Congress in Computational Mechanics (WCCM 2018), New York (USA)

Abstract
Brash ice is the accumulation of floating ice made up of blocks no larger than two meters across. Navigation in brash ice is becoming more usual as new navigation routes are being opened in the Artic regions. This navigation brings new concerns regarding the interaction of ice blocks with the ship. This work presents recent advances towards the development of a computational model for simulation of this navigation condition including the interaction among the ship and the ice blocks. The computational tool developed in this work is based on the coupling of a Semi-Lagrangian Particle Finite Element Method (SL-PFEM) with a multi rigid-body dynamics tool. The Particle Finite Element Method (Idelsohn et al. 2004) is a versatile framework for the analysis of fluid-structure interaction problems. The PFEM combines Lagrangian particle-based techniques with the advantage of the integral formulation of the Finite Element Method (FEM). It has been shown (Idelsohn et al. 2014 and Nadukandi et al. 2017) to successfully simulate a wide variety of complex engineering problems, e.g. free-surface/multi-fluid flows with violent interface motions, multi-fluid mixing and buoyancy-driven segregation problems etc. The latest development within the framework of the PFEM is the X-IVAS (eXplicit Integration along the Velocity and Acceleration Streamlines) scheme. It is a semi-implicit scheme built over a Semi-Lagrangian (SL) formulation of the PFEM. In this work, the SL-PFEM model has been coupled with a multibody dynamics solver, able to handle the interactions between thousands of bodies, representing the different ice blocks. The interaction between the fluid flow and the ice blocks is taking into account by enriching the finite element space at the boundaries of the different blocks. This work is part of the research project NICESHIP sponsored by the U.S. Office of Naval Research under Grant N62909-16-1-2236.
Abstract
Brash ice is the accumulation of floating ice made up of blocks no larger than two meters across. Navigation in brash ice is becoming more usual as new navigation routes are [...]
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Caracterización experimental y numérica de hormigones porosos modificados con polímeros
A. Aguado, A. Josa, M. Pindado

Monograph CIMNE (1997). M37

Abstract
Se pretende realizar una revisión completa de la experiencia obtenida tanto en gabinete de obra, mostrando las conclusiones de las mismas.
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Analysis of fractional step finite element methods for the incompressible Navier-Stokes equation
J. Blasco, R. Codina, A. Huerta

Monograph CIMNE (1997). M38

Abstract
This monograph is devoted to the study of fractional step, finite element methods for the numerical solution of incompressible, viscous flow equations, and in particular of the Navier-Stokes equations.
Abstract
This monograph is devoted to the study of fractional step, finite element methods for the numerical solution of incompressible, viscous flow equations, and in particular of [...]
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Metodología de evaluación del deterioro en estructuras de hormigón armado
A. Hanganu, A. Barbat, E. Oñate

Monograph CIMNE (1997). M39

Abstract
Se desarrolla la formulación de un Nuevo índice de daño global riguroso, general, selectivo y objetivo. En base a ésta se propone una metodología de evaluación de la degradación estructural apoyada en la correlación entre índices globales de distintas zonas. Dicha metodología tiene aplicaciones directas en el estudio de patologías de edificios, cálculo de cargas últimas y mecanismos de fallo.
Abstract
Se desarrolla la formulación de un Nuevo índice de daño global riguroso, general, selectivo y objetivo. En base a ésta se propone una metodología [...]
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Error estimation and adaptivity in strain localisation problems with softening materials
M. Arroyo, P. Díez, A. Huerta

Monograph CIMNE (1997). M40

Abstract
The study and prediction of failure is one of the most challenging issues of mechanical ans¡d structural engineering. In this context, an accurate analysis of strain localization, which typically triggers failure in many softening materials such as steel or concrete, is of great interest. The classical limit-state methods used to study localization phenomena are insufficient, and the finite element method appears as a proper analysis tool. Unfortunately, the numerical simulation of strain localisation in continuum mechanics has to face two important difficulties: the need of a mathematically consistent constitutive model on one side, and of a cost-effective computational strategy capable of capturing the multi-scale nature of localisation problems on the other side. Several formulations have appeared to overcome the fisrt challenge, usually known as regularization techniques or localisation limiters. On the order hand, adaptivity appears as the natural solution to the computational difficulty. In the present work, an adaptive remeshing procedure based on a residual type error estimator is presented in the context of quasi-static localisation problems with softening materials. Two well-known localisation limiters have been used: rate dependence has been used to regularize J2 softening plasticity (via Perzyna viscoplasticity) presenting shear band localisation, and the Mazars damage model with nonlocal regularization has been applied to simulate fracture localisation. These constitutive models simulate steel and concrete respectively. Numerical examples show the good performance of the presented procedure, that captures accurately and cost-effectively the micro-scale of strain localisation problems.Furthermore, this error estimator driven adaptive procedure constitutives an objective alternative to the usual approaches that are based on error indicators. Several topics of interest are also dealt with throughout the work, such as the analysis of the shear band width in quasi-static two-dimensional problems with Perzyna viscoplasticity, the influence of pollution errors in the adaptive process, or the use of error estimation analysis to deduce or test indicators.
Abstract
The study and prediction of failure is one of the most challenging issues of mechanical ans¡d structural engineering. In this context, an accurate analysis of strain [...]
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Scipedia and Science Shops
J. García-Espinosa

Presentations Repository of Scipedia (2018). 2

Abstract
Scipedia (https://www.scipedia.com) is a comprehensive and unparalleled solution for the needs of open access / open data / open innovation / open science. Scipedia.com essentially integrates an advanced online publishing and data management platform within a collaborative social network. Scipedia offers free (and premium) publishing and data repository management services on the platform Scipedia.com and the possibility to build customized solutions for institutions (institutional open science portals). This presentation focuses on the application of Scipedia for the implementation of Science shops in the context of the R&D project Scishops.
Abstract
Scipedia (https://www.scipedia.com) is a comprehensive and unparalleled solution for the needs of open access / open data / open innovation / open science. Scipedia.com [...]
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Reflexiones sobre el tránsito de la idea al producto en el entorno de la Escuela de Ingenieros de Caminos de Barcelona
E. Oñate

(2011). Research Report, Nº PI359

Abstract
Se presentan unas reflexiones sobre el ciclo que las ideas recorren desde que surgen en un entorno universitario hasta que se transforman en un producto industrial. Se concretan estas reflexiones en el contexto de la Escuela Técnica Superior de Ingenieros de Caminos, Canales y Puertos de la Universitat Politècnica de Catalunya y se presentan algunos ejemplos de éxitos en la implantación del denominado Círculo de las Ideas.
Abstract
Se presentan unas reflexiones sobre el ciclo que las ideas recorren desde que surgen en un entorno universitario hasta que se transforman en un producto industrial. Se concretan [...]
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Estabilización de la solución por elementos finitos de problemas de flujo incompresible con rotación, turbulencia, superficie libre y temperatura
O. Soto, R. Codina

Monograph CIMNE (1997). M41

Abstract
El principal objetivo del presente trabajo es el de plantear un método de solución por elementos finitos de las ecuaciones que rigen el flujo incompresible, tanto en su régimen laminar como turbulento. Adicionalmente se planteará un esquema para solucionar problemas que involucren el tratamiento de superficies libres y del flujo térmico. La solución a dichos problemas es la base para atacar diversos problemas de ingeniería que se presentan diariamente en la industria, tales como el llenado de moldes, el flujo en reactores químicos, el diseño de perfiles óptimos para ventiladores, barcos, etc. En este trabajo se presentan las ecuaciones que describen el comportamiento de un fluido incompresible en régimen laminar (ecuaciones de Navier-Stokes) y turbulento (ecuaciones de Reynolds), para luego plantear su solución por elementos finitos utilizando el método clásico o método de Galerkin.
Abstract
El principal objetivo del presente trabajo es el de plantear un método de solución por elementos finitos de las ecuaciones que rigen el flujo incompresible, [...]
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High-order accurate time-stepping schemes for convection-diffusion problems
J. Donea, B. Roig, A. Huerta

Monograph CIMNE (1998). M42

Abstract
In this work, a study has been made of other high order time-stepping methods with the view of identifying schemes that could possibly be used for a time accurate finite element solution of transient problems describing convective-diffusive transport. Both explicit and implicit methods are considered.
Abstract
In this work, a study has been made of other high order time-stepping methods with the view of identifying schemes that could possibly be used for a time accurate finite element [...]
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Analysis of beams and shell using a rotation - free finite element - finite volume formulation
J. Jovicevic, E. Oñate

Monograph CIMNE (1998). M43

Abstract
In this research work, the studies of the previous authors have been applied and expanded to other types of structural problems: Euler-Bernoulli beams, axisymmetric shells and arbitrary shape shells. The main novelty of the particular interest in this work is recasting the mentioned developments in the framework of the mixed Hu-Washizu type variational formulation. Different FE/EV approximations have been accommodated owing to such a variational formulation, in particular Cell Centered and Cell Vertex FV schemes combined with simple linear finite element interpolation have been studied.
Abstract
In this research work, the studies of the previous authors have been applied and expanded to other types of structural problems: Euler-Bernoulli beams, axisymmetric shells [...]
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Localización de deformaciones: análisis y simulación numérica de discontinuidades en mecánica de sólidos
O. Manzoli, J. Oliver, M. Cervera

Monograph CIMNE (1998). M44

Abstract
El objetivo principal del presente trabajo es extender la clase de aproximación de discontinuidad fuerte, originalmente propuesta por Simó, Oliver y Armero (1993), con objeto de contemplar la posibilidad del empleo de leyes de endurecimiento cualesquiera para representar el comportamiento del material. Además, se busca establecer el vínculo definitivo entre los modelos teóricos continuos, que consideran que la localización se asocia a la formación de superficies de discontinuidad débil, y la teoría discontinua, que asocia la localización con la formación de superficies de discontinuidad fuerte.
Abstract
El objetivo principal del presente trabajo es extender la clase de aproximación de discontinuidad fuerte, originalmente propuesta por Simó, Oliver y Armero (1993), [...]
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Lagrangian FE methods for coupled problems in fluid mechanics
P. Ryzhakov, E. Oñate, R. Rossi, S. Idelsohn

Monograph CIMNE (2010). M121

Abstract
Lagrangian finite element methods emerged in fluid dynamics when the deficiencies of the Eulerian methods in treating free surface flows (or generally domains undergoing large shape deformations) were faced. Their advantage relies upon natural tracking of boundaries and interfaces, a feature particularly important for interaction problems. Another attractive feature is the absence of the convective term in the fluid momentum equations written in the Lagrangian framework resulting in a symmetric discrete system matrix, an important feature in case iterative solvers are utilized. Unfortunately, the lack of the control over the mesh distortions is a major drawback of Lagrangian methods. In order to overcome this, a Lagrangian method must be equipped with an efficient re-meshing tool. This work aims at developing formulations and algorithms where maximum advantage of using Lagrangian finite element fluid formulations can be taken. In particular we concentrate our attention at fluid-structure interaction and thermally coupled applications, most of which originate from practical “real-life” problems. Two fundamental options are investigated - coupling two Lagrangian formulations (e.g. Lagrangian fluid and Lagrangian structure) and coupling the Lagrangian and Eulerian fluid formulations. In the first part of this work the basic concepts of the Lagrangian fluids, the so-called Particle Finite Element Method (PFEM) [1], [2] are presented. These include nodal variable storage, mesh re-construction using Delaunay triangulation/tetrahedralization and alpha shape-based method for identification of the computational domain boundaries. This shall serve as a general basis for all the further developments of this work. Next we show how an incompressible Lagrangian fluid can be used in a partitioned fluid-structure interaction context. We present an improved Dirichlet-Neumann strategy for coupling the incompressible Lagrangian fluid with a rigid body. This is finally applied to an industrial problem dealing with the sea-landing of a satellite capsule. In the following, an extension of the method is proposed to allow dealing with fluid-structure problems involving general flexible structures. The method developed takes advantage of the symmetry of the discrete system matrix and by introducing a slight fluid compressibility allows to treat the fluid-structure interaction problem efficiently in a monolithic way. Thus, maximum benefit from using a similar description for both the fluid (updated Lagrangian) and the solid (total Lagrangian) is taken. We show next that the developed monolithic approach is particularly useful for modeling the interaction with light-weight structures. The validation of the method is done by means of comparison with experimental results and with a number of different methods found in literature. The second part of this work aims at coupling Lagrangian and Eulerian fluid formulations. The application area is the modeling of polymers under fire conditions. This kind of problem consists of modeling the two subsystems (namely the polymer and the surrounding air) and their thermomechanical interaction. A compressible fluid formulation based on the Eulerian description is used for modeling the air, whereas a Lagrangian description is used for the polymer. For the surrounding air we develop a model based upon the compressible Navier-Stokes equations. Such choice is dictated by the presence of high temperature gradients in the problem of interest, which precludes the utilization of the Boussinesq approximation. The formulation is restricted to the sub-sonic flow regime, meeting the requirement of the problem of interest. The mechanical interaction of the subsystems is modeled by means of a one-way coupling, where the polymer velocities are imposed on the interface elements of the Eulerian mesh in a weak way. Thermal interaction is treated by means of the energy equation solved on the Eulerian mesh, containing thermal properties of both the subsystems, namely air and polymer. The developments of the second part of this work do not pretend to be by any means exhaustive; for instance, radiation and chemical reaction phenomena are not considered. Rather we make the first step in the direction of modeling the complicated thermo-mechanical problem and provide a general framework that in the future can be enriched with a more detailed and sophisticated models. However this would affect only the individual modules, preserving the overall architecture of the solution procedure unchanged. Each chapter concludes with the example section that includes both the validation tests and/or applications to the real-life problems. The final chapter highlights the achievements of the work and defines the future lines of research that naturally evolve from the results of this work.
Abstract
Lagrangian finite element methods emerged in fluid dynamics when the deficiencies of the Eulerian methods in treating free surface flows (or generally domains undergoing [...]
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Elementos estabilizados de bajo orden en mecánica de sólidos
Q. Valverde, C. Saracibar, M. Cervera, M. Chiumenti

Monograph CIMNE (2002). M69

Abstract
El objetivo de este trabajo es desarrollar e implementar una formulación específica, robusta y precisa de elementos, capaz de abordar el problema de incompresibilidad en mecánica de sólidos, con modelos constitutivos elásticos y elasto-plásticos J2, tanto en el contexto de las deformaciones infinitesimales como de las grandes deformaciones.
Abstract
El objetivo de este trabajo es desarrollar e implementar una formulación específica, robusta y precisa de elementos, capaz de abordar el problema de incompresibilidad [...]
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Pre y postprocesadores para el cálculo de estructuras. Interface GiD-Sap90
F. Muñoz, J. Maristany

Monograph CIMNE (1999). M52

Abstract
La integración (interface) de los programas, por un lado el pre y postproceso y por el otro el análisis de estructuras por medio del MEF, GiD y Sap90 nos permiten de forma ágil y sencilla realizar el análisis de cualquier género estructural, por compleja que sea.
Abstract
La integración (interface) de los programas, por un lado el pre y postproceso y por el otro el análisis de estructuras por medio del MEF, GiD y Sap90 nos permiten [...]
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Scipedia's hosting plans for journals
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A non-linear finite element method on unstructured meshes for added resistance in waves
J. García-Espinosa, B. Servan Camas

Ships and offshore structures (2018). 14:2, 153-164 (preprint)

Abstract
In this work a finite element method (FEM) is proposed to solve the problem of estimating the added resistance of a ship in waves in the time domain and using unstructured meshes. Two different schemes are used to integrate the corresponding free surface kinematic and dynamic boundary conditions: the first one based on streamlines integration (SLI); and the second one based on the Streamline-Upwind Petrov-Galerking (SUPG) stabilization. The proposed numerical schemes have been validated in different test cases, including towing tank tests with monochromatic waves. The results obtained in this work show the suitability of the present method to estimate added resistance in waves in a computationally affordable manner.
Abstract
In this work a finite element method (FEM) is proposed to solve the problem of estimating the added resistance of a ship in waves in the time domain and using unstructured [...]
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Excellent science with and for all: the case of CIMNE
C. Soriano

Presentations Repository of Scipedia (2018). 1

Abstract
This presentation was held on 5th July, 2018 at the VII Session of the Virtual Program on Open Science and Research Data Management (VII Sesión del Programa Virtual sobre Ciencia Abierta y Gestión de Datos de Investigación) organized by Columbus Foundation. The presentation shows different activities of the International Center for Numerical Methods in Engineering (CIMNE) in the field of Open Science, and in particular it presents the innovative Open Science platform Scipedia.com.
Abstract
This presentation was held on 5th July, 2018 at the VII Session of the Virtual Program on Open Science and Research Data Management (VII Sesión del Programa Virtual [...]
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1st FIBRESHIP WORKSHOP - General Overview
I. GARCIA

Open Access Repository of the FIBRESHIP project (2018). 4

Abstract
This introductory presentation was made on the 1st Fibreship Workshop (14th May 2018, London).
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1st FIBRESHIP WORKSHOP - Breakout Session 3 - Engineering
S. paboeuf, A. CASSEZ

Open Access Repository of the FIBRESHIP project (2018). 3

Abstract
This presentation was made on the 1st Fibreship Workshop to show the advances made in the project regarding the engineering aspects (mainly related to fire assessment and structural design).
Abstract
This presentation was made on the 1st Fibreship Workshop to show the advances made in the project regarding the engineering aspects (mainly related to fire assessment and [...]
- 0
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1st FIBRESHIP WORKSHOP - Breakout Session 2 - Computational Analysis Tools
J. García-Espinosa, O. Casals

Open Access Repository of the FIBRESHIP project (2018). 2

Abstract
This presentation was made on the 1st Fibreship Workshop to show the advances made in the project regarding the development of different analysis tools to support design and inspection of large length FRP based ships.
Abstract
This presentation was made on the 1st Fibreship Workshop to show the advances made in the project regarding the development of different analysis tools to support design and [...]
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1st FIBRESHIP WORKSHOP - Breakout Session 1 - Materials
X. Martinez

Open Access Repository of the FIBRESHIP project (2018). 1

Abstract
Presentation made on the 1st Fibreship Workshop to show the advances made in the project regarding the material selection and characterization.
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On application of two superconvergent recovery procedures to plate problems
B. Boroomand, M. Ghaffarian, O. Zienkiewicz

(2004). Research Report, Nº PI247

Abstract
In this paper a study is performed on application of two recovery methods, i.e. Superconvergent Patch Recovery (SPR) and the Recovery by Equilibrium of Patches (REP), to plate problems. The two recovery methods have been recognized to give similar results in adaptive solutions of two dimensional stress problems. While the former applies a least square fit over a set of values at the so called superconvergent points, the latter does not need any knowledge of such points and thus has a wider application especially in non-linear problems. The formulation of REP is extended to Reissner-Mindlin plate problems. The convergence rates of the recovered fields of the gradients obtained from application of the two methods are compared using series of regular triangular and rectangular meshes for thick and thin plate solution cases. Assumed strain formulation based elements, i.e. the elements formulated by Mixed Interpolation of Tensorial Components, as well as conventional from of elements based on selective integration schemes are employed for the study. In order to investigate the possibility of any improvement in the results by adding equilibrium constraints to SPR, as some authors suggest for simple two-dimensional problems, some weighted forms of such conditions are designed and added to the formulation. Comprehensive study has been given first by varying the weight terms to obtain the best enhanced results and then using the optimal values to investigate the effects of the constraints on the rate of convergence. It is observed that despite of the cost of this approach, due to the coupling of the gradient terms, no significant improvement is achieved.
Abstract
In this paper a study is performed on application of two recovery methods, i.e. Superconvergent Patch Recovery (SPR) and the Recovery by Equilibrium of Patches (REP), to plate [...]
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Advances in the Simulation of Ship Navigation in Ice
J. García-Espinosa, B. Servan Camas, J. Colom Cobb, E. Oñate, S. Latorre, M. Celigueta

37th International Conference on Ocean, Offshore & Arctic Engineering (OMAE 2018), Madrid (Spain)

Abstract
Brash ice is the accumulation of floating ice made up of blocks no larger than two meters across. Navigation in brash ice is becoming more usual as new navigation routes are being opened in the Artic regions. This navigation brings new concerns regarding the interaction of ice blocks with the ship. This work presents recent advances towards the development of a computational model for simulation of this navigation condition including the interaction among the ship and the ice blocks. The computational tool developed in this work is based on the coupling of a Semi-Lagrangian Particle Finite Element Method (SL-PFEM) with a multi rigid-body dynamics tool. The Particle Finite Element Method (Idelsohn et al. 2004) is a versatile framework for the analysis of fluid-structure interaction problems. The PFEM combines Lagrangian particle-based techniques with the advantage of the integral formulation of the Finite Element Method (FEM). It has been shown (Idelsohn et al. 2014 and Nadukandi et al. 2017) to successfully simulate a wide variety of complex engineering problems, e.g. free-surface/multi-fluid flows with violent interface motions, multi-fluid mixing and buoyancy-driven segregation problems etc. The latest development within the framework of the PFEM is the X-IVAS (eXplicit Integration along the Velocity and Acceleration Streamlines) scheme. It is a semi-implicit scheme built over a Semi-Lagrangian (SL) formulation of the PFEM. In this work, the SL-PFEM model has been coupled with a multibody dynamics solver, able to handle the interactions between thousands of bodies, representing the different ice blocks. The interaction between the fluid flow and the ice blocks is taking into account by enriching the finite element space at the boundaries of the different blocks. This work is part of the research project NICESHIP sponsored by the U.S. Office of Naval Research under Grant N62909-16-1-2236.
Abstract
Brash ice is the accumulation of floating ice made up of blocks no larger than two meters across. Navigation in brash ice is becoming more usual as new navigation routes are [...]
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El sector Náutico en España - 2012
F. ANEN

Informes Nauticos (2018). 2

Abstract
Informe del Sector Náutico en España ( 2012). La Náutica deportiva y de Recreo. Informe elaborado por del departamento de Investigación y estrategia de mercado de la Fira de Barcelona en colaboración con la Asociación Nacional de Empresas Náuticas (ANEN)
Abstract
Informe del Sector Náutico en España ( 2012). La Náutica deportiva y de Recreo. Informe elaborado por del departamento de Investigación y estrategia [...]
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Informe sobre el sector del chárter en España Temporada 2015
R. Nautal

Informes Nauticos (2018). 1

Abstract
La empresa Nautal, nos facilita este informe del sector del chárter en España obtenido de su actividad como como agencia. es de los primeros informes sobre la actividad del charter
Abstract
La empresa Nautal, nos facilita este informe del sector del chárter en España obtenido de su actividad como como agencia. es de los primeros informes sobre la [...]
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Intervenció professor Andreu Mas-Colell
A. Mas-Colell

Acte final del 3r Congrés d'Economia i Empresa de Catalunya (2018). 3
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Catalunya en clau macroeconòmica en un entorn global
T. Garcia-Milà

Acte final del 3r Congrés d'Economia i Empresa de Catalunya (2018). 2
- 3
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L’empresa com a procés continu d’adaptació
J. Pont

Acte final del 3r Congrés d'Economia i Empresa de Catalunya (2018). 1
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Quality management in the university classroom
W. Ortiz

Gaceta Técnica (2018). Vol. 19 (1), 5

Abstract
This study aimed to address quality management in the university classroom, specifically in the Department of Basic Sciences of the Dean of Civil Engineering of the Universidad Centroccidental Lisandro Alvarado. It was conceived under the modality of qualitative research of ethnographic type with an interpretive character. The research process involved three phases: obtaining information, in which key informants were selected from a group of four (4) teachers and three (3) students in an intentional sampling, interview techniques were applied and participant observation to record and categorize the informants' opinions. In the second phase, the analysis and interpretation of the information was done using the GLATER model, which allowed orientating it from four stages: the first stage assignment of codes and dimensions, second stage of description, third of categorization and fourth stage of interpretation. In the third and final phase the construction of a theoretical approach of the quality management based on the managerial method PDCA, proposed by the researcher, was carried out starting from the analysis of the categories and their properties. As a result of this process, the thematic categories emerged: Integral Training, Availability and Use of School Media, Dynamics of Organizational Learning and Institutional Leadership.
Abstract
This study aimed to address quality management in the university classroom, specifically in the Department of Basic Sciences of the Dean of Civil Engineering of the Universidad [...]
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Alternative procedure to determine the response reduction factor for ductile RC framed buildings
J. Perez, M. Oca, W. Quintero

Gaceta Técnica (2018). Vol. 19 (1), 11

Abstract
The seismic design is based on the results of the structures elastic analysis, even though now days the nonlinear analysis is increasingly accessible. To perform the seismic analysis of structures that are modeled with elastic behavior, but known to venture into the plastic behavior, the standards establish the reduction of the elastic design spectra by the use of reduction factors, formulated essentially on the basis of the engineering judgment. This paper proposes a strategy to obtain response reduction factors, based on the results of non-linear analysis of soil response and structural systems with a degree of freedom, along with the nonlinear response of multiple grade of freedom framed structural systems by armed concrete, for the specific spectra of Venezuela. The results of response reductions factors were greater than the current values of response reduction prescribed by the Venezuelan seismic code, which can favorably lead to a displacement-based design instead strength-based design.
Abstract
The seismic design is based on the results of the structures elastic analysis, even though now days the nonlinear analysis is increasingly accessible. To perform the seismic [...]
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A river bed hydrokinetic turbine - a laminated composite material rotor design
S. Oller-Aramayo, L. Nallim, S. Oller, X. Martínez

Monograph CIMNE (2017). M169

Abstract
This work presents the composite materials applied to Water Current Turbine (WCT) hydrokinetic turbines. Here will be briefly described the features of these turbines, the fluid-dynamic behavior of the rotor, and its structure formed into a composite material. From the structural viewpoint an advanced composite material formulation that allows an appropriate structural design is introduced. The generalized composite formulations here introduced take into account the nonlinear mechanical behavior of the component materials (matrix and fiber), as the local behavior of plasticity and damage, its anisotropy, the fiber matrix debonding, its material composition via a general mixing theory, and also the homogenized structural damage index definition. Hydrokinetic turbines bring newer advantages and greater possibilities for green hydroelectric power generation. For this reason, achieving a very high lift blade rotor to take the maximum kinetic energy advantage for rivers with a slow velocity flow is very important. A very low inertia rotor permits a self-starting effect for the axial water flow turbine to take the maximum advantage of the river kinetic energy which is very important in this kind of devices. A turbine rotor hydrofoil made in composite material can be designed for this purpose. One of the most commonly used composite material analysis formulation is herein introduced. Specifically, a particular Serial/Parallel (S/P) Mixing Theory with a better relation between model accuracy vs. computational cost is provided. In front to other formulation, the S/P Mixing Theory not increasing the degrees of freedom of the problem because is a constitutive formulation. A brief introduction to fluid-dynamic concept involving in the analysis of a rotor of this type of turbines is presented. This allows seeing the origin of the actions applied to the rotor of this type of turbines. In addition, two simple examples that show the potentiality of the model are presented in this chapter. Then, an application to the design of a rotor blade of a passing turbine, made of carbon fiber-reinforced matrix composite material, is shown.
Abstract
This work presents the composite materials applied to Water Current Turbine (WCT) hydrokinetic turbines. Here will be briefly described the features of these turbines, the [...]
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Static and Seismic Analysis of the Janneh Arch-gravity Dam
L. Gracia, I. de-Pouplana, F. Salazar, E. Oñate

(2017). 14th International Benchmark Workshop on the Numerical Analysis of Dams. Stockholm, Sweden, 2017

Abstract
The static and seismic analysis of Janneh arch-gravity dam (157 m) is carried out by considering a combination of self-weight, hydrostatic, uplift and seismic loads. Linear and nonlinear analyses are performed for both static and seismic cases. Nonlinear behavior is studied by means of joint elements in the contact between the rock foundation and the dam following a bilinear cohesive law. The hydrodynamic effects derived to seismic loads are also considered. Hydrodynamic Westergaard’s approach is applied in the pseudo-static analysis, and the Westergaard’s generalized added mass is used for time-history case.
Abstract
The static and seismic analysis of Janneh arch-gravity dam (157 m) is carried out by considering a combination of self-weight, hydrostatic, uplift and seismic loads. Linear [...]
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Alternative procedure to determine the response reduction factor for ductile RC framed buildings
J. Perez, M. Oca, W. Quintero

Gaceta Técnica (2018). Vol. 19 (1), 4

Abstract
The seismic design is based on the results of the structures elastic analysis, even though now days the nonlinear analysis is increasingly accessible. To perform the seismic analysis of structures that are modeled with elastic behavior, but known to venture into the plastic behavior, the standards establish the reduction of the elastic design spectra by the use of reduction factors, formulated essentially on the basis of the engineering judgment. This paper proposes a strategy to obtain response reduction factors, based on the results of non-linear analysis of soil response and structural systems with a degree of freedom, along with the nonlinear response of multiple grade of freedom framed structural systems by armed concrete, for the specific spectra of Venezuela. The results of response reductions factors were greater than the current values of response reduction prescribed by the Venezuelan seismic code, which can favorably lead to a displacement-based design instead strength-based design.
Abstract
The seismic design is based on the results of the structures elastic analysis, even though now days the nonlinear analysis is increasingly accessible. To perform the seismic [...]
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Characterization of the public and massive construction of social interest houses developed since 2005 in Lara State. Venezuela
J. Lucena, K. Vallejo, M. Jaua

Gaceta Técnica (2018). Vol. 19 (1), 2

Abstract
The main objective of this research is the public and massive construction of social interest housing, executed between 2005 and 2015 in the Iribarren and Palavecino municipalities of Lara State, Venezuela, in order to continue the investigation carried out in the years between 1994 and 2005, through the determination of evaluation parameters related to the design and construction characteristics of town planning and housing. It is a field research, not experimental descriptive, the representation shows 355 houses in 5 urbanisms. The relevant results showed a better architectural distribution of the houses than the ones developed in previous years, it showed an 80 % of urban equipment, 20,56% of the houses enclosures problems, 26,42% problems related to the soil, 16.9% reveals the entry of rain water and through windows 12.68% presents rain water entry through the door. Although the percentages of housing failures have been reduced, the percentages of faults in infrastructure services have increased, that is, better homes that lack basic services have been built. Recommending taking advantage of the identified opportunities for improvement.
Abstract
The main objective of this research is the public and massive construction of social interest housing, executed between 2005 and 2015 in the Iribarren and Palavecino municipalities [...]
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Key issues in computational geomechanics
A. Pérez-Foguet, A. Rodríguez-Ferran, A. Huerta

Monograph CIMNE (2000). M58

Abstract
As stated in the introduction, the three main topics covered in this report are actual research fields. Different analyses and new developments related with these fields have been presented in the previous chapters. In the following, after a brief summary of the contributions, some directions for future research are outlined. Detailed presentations of the conclusions of each contribution are included in the corresponding sections and subsections. The most relevant contributions of this report are the following: 1. With respect to the treatment of large boundary displacements: > Quasistatic and dynamic analyses of the vane test for soft materials using a fluid–based ALE formulation and different non-newtonian constitutive laws. > The development of a solid–based ALE formulation for finite strain hyperelastic–plastic models, with applications to isochoric and non-isochoric cases. 2. Referent to the solution of nonlinear systems of equations in solid mechanics: > The use of simple and robust numerical differentiation schemes for the computation of tangent operators, including examples with several non-trivial elastoplastic constitutive laws. > The development of consistent tangent operators for substepping time–integration rules, with the application to an adaptive time–integration scheme. 3. In the field of constitutive modelling of granular materials: > The efficient numerical modelling of different problems involving elastoplastic models, including work hardening–softening models for small–strain problems and density– dependent hyperelastic–plastic models in a large–strain context. > Robust and accurate simulations of several powder compaction processes, with detailed analysis of spatial density distributions and verification of the mass conservation principle.
Abstract
As stated in the introduction, the three main topics covered in this report are actual research fields. Different analyses and new developments related with these fields [...]
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RESILTRACK Resiliencia de infraestructuras ferroviarias frente a Cambio Climático (Presentación CIMNE p/ Kick-off)
E. participantes, O. Fruitos, O. Fruitos Bickham

RESILTRACK Project (2018). 3

Abstract
The RESILTRACK OBJECTIVE is to design a system which allows the knowledge of the infrastructure state and its affectation before climatic adverse real time phenomena, as well as prevent its behavior to act; where necessary, obtaining therefore railway infrastructures resilient before the effects of the climate change. Document: Kick off CIMNE presentation
Abstract
The RESILTRACK OBJECTIVE is to design a system which allows the knowledge of the infrastructure state and its affectation before climatic adverse real time phenomena, [...]
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Incremental dynamic analysis and pushover analysis of buildings. A probabilistic comparison
Y. Vargas, A. Barbat, L. Pujades, J. Hurtado

(2013). Computational Methods in Stochastic Dynamics, Volume 2, Springer, ISBN: 978-94-007-5134-7, 293-308

Abstract
Capacity-spectrum-based-methods areused for assessing the vulnerability and risk of existing buildings. Capacity curves are usually obtained by means of nonlinear static analysis. Incremental Dynamic Analysis is a powerful tool based on nonlinear dynamic analysis. This method can provide results similar to the pushover analysis as the input is increasingly enlarged. It is well known that the randomness associated to the structural response can be significant, because of the uncertainties involved in the mechanical properties of the materials, among others uncertainty sources, and because the expected seismic actions are also highly stochastic. In this chapter, selected mechanical properties are considered as random variables and the seismic hazard is considered in a probabilistic way. A number of accelerograms of actual European seismic events have been selected in such a way that their response spectra fit well the response spectra provided by the seismic codes for the area where the building is constructed.A fully probabilistic approach is tackled herein by means of Monte Carlo simulation. The method is applied to a detailed study of the seismic response of a reinforced concrete building. The main purposes of this work are 1) to analyze the differences when static and dynamic techniques are used and 2) to obtain a measure of the uncertainties involved in the assessment of the vulnerability of structures. The results show that static based procedures are somehow conservative and that uncertainties increase with the severity of the seismic actions and with the damage. Low damage state fragility curves have little uncertainty while high damage grades fragility curves show great scattering.
Abstract
Capacity-spectrum-based-methods areused for assessing the vulnerability and risk of existing buildings. Capacity curves are usually obtained by means of nonlinear static analysis. [...]
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Indicators for hazard, exposure and urban risk
M. Carreño, A. Barbat, M. Marulanda

(2012). Modelación probabilista para la gestión del riesgo de desastre, The World Bank, 73-89

Abstract
The difficulty of considering aspects such as the effectiveness of risk management or the ability to react in the event of a disaster in a single methodology of risk analysis requires using techniques based on indicators. Indicators, which reflect different aspects of risk components, are reference values of the hazard, exposure, vulnerability or risk that consider physical economic, social and environmental aspects. The main application of a system of risk indicators is to assess all these aspects in a geographical area, which can be a country, a subnational region or a city and to allow a detailed analysis of the urban area. The basic indicators at the city level that are necessary to perform risk assessments and are presented in this chapter are the following: physical exposure indicators, economic exposure indicators, population exposure indicators, hazard and physical risk indicators, total risk index for holistic risk estimation and the risk management index.
Abstract
The difficulty of considering aspects such as the effectiveness of risk management or the ability to react in the event of a disaster in a single methodology of risk analysis [...]
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Social Aggravation Estimation to Seismic Hazard Using Classical Fuzzy Methods
J. Cárdenas, A. Nebot, F. Mugica, M. Carreño, A. Barbat

(2015). Simulation and Modeling Methodologies, Technologies and Applications, Springer, ISBN 978-3-319-26469-1, 275-293

Abstract
In the years, from a disasters perspective, risk has been dimensioned to allow a better management. However, this conceptualization turns out to be limited or constrained by the generalized use of a fragmented risk framework, which always consider first the approach and applicability of each discipline involved. To be congruent with risk definition, it is necessary to consider an integral framework, and social factors must be included. Even those indicators that could tell something about the organizational and institutional capacity to withstand natural hazards, should be invited to the table. In this article, we analyze one of the most important elements in risk formation: the social aggravation, which can be regarded as the convolution of the resilience capacity and social fragility of an urban center. We performed a social aggravation estimation over Barcelona, Spain, and Bogota, Colombia, considering a particular hazard in the form of seismic activity. The aggravation coefficient was formulated through a Mamdami fuzzy approach, supported by well-established fuzzy theory, which is characterized by a high expressive power and an intuitive humanlike manner.
Abstract
In the years, from a disasters perspective, risk has been dimensioned to allow a better management. However, this conceptualization turns out to be limited or constrained [...]
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Seismic Response of RC Framed Buildings Designed According to Eurocodes
J. Vielma, A. Barbat, S. Oller

(2011). Computational Methods in Applied Sciences, Springer, ISBN 978-94-007-0052-9, 201-220

Abstract
In order to ensure that a building structure do not collapse when subjected to the action of strong ground motions, modern codes include prescriptions in order to guarantee the ductile behavior of the elements and of the whole structure. Obviously, it is of special importance for the designer to know during the design process the extent of damage that the structure will suffer under the seismic action specified by the design spectrum and also the probability of occurrence of different states of behaviour. The incremental nonlinear static analysis procedure used in this paper allows formulating a new, simplified, seismic damage index and damage thresholds associated with five limit states. The seismic behavior of a set of regular reinforced concrete buildings designed according to the EC-2/EC-8 prescriptions for a high seismic hazard level is then studied using the proposed damage index and damage states. Fragility curves and damage probability matrices corresponding to the performance point are calculated for the studied buildings. The obtained results show that the collapse damage state is not reached in the buildings designed according the prescriptions of EC-2/EC-8 and also that the damage does not exceed the irreparable damage limit state.
Abstract
In order to ensure that a building structure do not collapse when subjected to the action of strong ground motions, modern codes include prescriptions in order to guarantee [...]
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VULNERABILITY ASSESSMENT OF DWELLING BUILDINGS
A. Barbat, S. Lagomarsino, L. Pujades

(2006). ASSESSING AND MANAGING EARTHQUAKE RISK, Springer, ISBN 10-1-4020-3524-1, 115-134

Abstract
Risk is defined as the potential economic, social and environmental consequences of hazardous events that may occur in a specified area unit and period. The evaluation of physical vulnerability and risk of buildings is the main purpose of this chapter. Nevertheless, it is shown the necessity of considering not only the expected physical damage but also the social fragility and the lack of resilience of the exposed community, that is, a holistic evaluation of risk aiming at guiding decision making. Both the vulnerability index and capacity spectrum methods for the evaluation of the physical risk are discussed herein. Both provide good results for the considered case study the urban area of Barcelona, Spain. Both methods show how a city, located in a low to moderate hazard region, which has paid no attention to the seismic performance of their buildings, has buildings with a high seismic vulnerability and a considerable seismic risk.
Abstract
Risk is defined as the potential economic, social and environmental consequences of hazardous events that may occur in a specified area unit and period. The evaluation of [...]
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NON LINEAR STRUCTURAL ANALYSIS. APPLICATION FOR EVALUATING SEISMIC SAFETY
J. Vielma, A. Barbat, S. Oller

(2010). Structural Analysis, Nova Science Publishers, ISBN 978-1-61668-987-2, 101-128

Abstract
Performance-Based Design is accepted commonly as the most advanced design and evaluation approach. However, its successful application depends on the ability to accurately estimate the parameters of structural response. The determination of these parameters requires applying analysis procedures where the non-linear behavior features of structures are included. This chapter presents and discusses these features of non-linear behavior and how they are incorporated in the process of static or dynamic structural analyses. Non-linear analysis allows obtaining from the seismic response significant structural response parameters such as ductility, overstrength, response reduction factor and damage thresholds. In order to illustrate the application of the non-linear analysis procedures, a set of concrete-reinforced moment-resisting framed buildings with various numbers of levels, was designed according to ACI-318 for high and very high level of seismic hazard. Their seismic safety is studied using both the static and dynamic non-linear analyses.
Abstract
Performance-Based Design is accepted commonly as the most advanced design and evaluation approach. However, its successful application depends on the ability to accurately [...]
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Holistic Evaluation of Seismic Risk in Barcelona
M. Carreño, A. Barbat, O. Cardona, M. Marulanda

(2014). Assessment of Vulnerability to Natural Hazards, Elsevier, ISBN: 978-0-12-410528-7, 21-52

Abstract
Within the framework described in Chapter 1, this chapter shows the evaluation of the seismic risk of the city of Barcelona, Spain, by applying a probabilistic analysis. On this basis a holistic evaluation of risk is performed taking into account social fragilityand lack of resilience aspects. Finally, the evaluation of the disaster risk management performance is conducted.
Abstract
Within the framework described in Chapter 1, this chapter shows the evaluation of the seismic risk of the city of Barcelona, Spain, by applying a probabilistic analysis. On [...]
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Theoretical and Conceptual Framework for the Assessment of Vulnerability to Natural Hazards and Climate Change in Europe
J. Birkmann, A. Barbat, O. Cardona, M. Carreño, M. Pelling, S. Schneiderbauer, S. Kienberger, M. Keiler, D. Alexander, P. Zeil, T. Welle

(2014). Assessment of Vulnerability to Natural Hazards, Elsevier, ISBN: 978-0-12-410528-7, 1-19

Abstract
This chapter outlines a framework for multidimensional, holistic vulnerability assessment that is understood as part of risk evaluation and risk management in the context of Disaster Risk Management and Climate Change Adaptation. As a heuristic, the framework is a thinking tool to guide systematic assessments of vulnerability and to provide a basis for comparative indicators and criteria development to assess key factors and various dimensions of vulnerability, particularly in regions in Europe. However, it can also be applied in other world regions. The framework has been developed within the context of the research project MOVE (Methods for the Improvement of Vulnerability Assessment in Europe; www.move-fp7.eu) sponsored by the European Commission within the framework of the FP 7 program.
Abstract
This chapter outlines a framework for multidimensional, holistic vulnerability assessment that is understood as part of risk evaluation and risk management in the context [...]
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Numerical analysis of of repair and reinforcement of structures with FRP
S. Oller, M. Molina, J. Vielma, X. Martínez, A. Barbat, L. Nallim

(2014). Aplicaciones avanzadas de los materiales compuestos, Omnia Publishers, ISBN: 978-84-941872-9-2, 261-291

Abstract
In this chapter, we present a procedure to evaluate the local damage and global damage in structures subjected to static and dynamic actions, with special emphasis on the seismic problem. In addition to the formulation for the evaluation of damage, we introduce the concept of reinforcement and structural repair by using laminated epoxy matrix composites with carbon fiber reinforcement. For this purpose, the theory of mixtures is used to define a composite material from its basic components. Damage is also evaluated in these reinforced and/or repaired structures and the influence of these improvements on the overall damage assessment of the structure is discussed.
Abstract
In this chapter, we present a procedure to evaluate the local damage and global damage in structures subjected to static and dynamic actions, with special emphasis on the [...]
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Revealing the Impact of Small Disasters to the Economic and Social Development
M. Marulanda, O. Cardona, A. Barbat

(2011). Coping with Global Environmental Change, Disasters and Security, Springer, ISBN 978-3-642-17776-7, 575-584

Abstract
This chapter presents the results of the evaluation of the proneness of Colombia to small scale and chronic disasters, and the type of impact they have for the local and country development. This analysis detected the spatial variability and dispersion of vulnerability and risk in the country because of events that rarely enter the international or even national disaster databases. But these events pose an accumulative development problem for local areas and, given their overall probable impacts, for the country as a whole. First, the database of small disasters used is described to identify the strengths and weaknesses of the available data and how that information was prepared for this research. A conceptual framework regarding the impact of small disasters is then presented, to characterize the risk associated to this type of disasters together with a quantification of their effects and their economic costs in order to illustrate their relevance due to the accumulated impact and recurrence. Finally, the conclusions of the study are given, which identify new risk concepts: The concept of ‘intensive risk’ to refer to the concentrated risk manifesting infrequently in specific locations, and the concept of ‘extensive risk’ to refer to the diffuse risk manifesting frequently over wide territories.
Abstract
This chapter presents the results of the evaluation of the proneness of Colombia to small scale and chronic disasters, and the type of impact they have for the local and country [...]
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Holistic Urban Seismic Risk Evaluation of Megacities: Application and Robustness
M. Carreño, O. Cardona, M. Marulanda, A. Barbat

(2009). The 1755 Lisbon Earthquake: Revisited, Springer, ISBN 978-1-4020-8609-0, 167-183

Abstract
From a holistic perspective, disaster risk requires a multidisciplinary evaluation that takes into account not only the expected physical damage, the number and type of casualties or economic losses, but also the conditions related to social fragility and lack of resilience conditions, which favor the second order effects when a hazard event strikes an urban center. In this chapter, the urban risk is evaluated using composite indicators or indices. Expected building damage and losses in the infrastructure, obtained from loss scenarios are basic information for the evaluation of the physical risk index in each unit of analysis. The holistic evaluation of disaster risk is achieved affecting the physical risk with an impact factor, obtained from contextual conditions, such as the socioeconomic fragility and the lack of resilience, that aggravate the physical risk. Available data about these conditions at urban level are necessary to apply the method. The model is explained and the benefits of this approach are illustrated, inviting to the risk management of urban centers.
Abstract
From a holistic perspective, disaster risk requires a multidisciplinary evaluation that takes into account not only the expected physical damage, the number and type of casualties [...]
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Neuro-fuzzy assessment of building damage and safety after an earthquake
M. Carreño, O. Cardona, A. Barbat

(2007). Intelligent computational paradigms in earthquake engineering, IDEA Group Publishing, ISBN: 1-59904-099-9, 123-157

Abstract
This chapter describes the algorithmic basis of a computational intelligence technique, based on a neuro-fuzzy system, developed with the objective of assisting nonexpert professionals of building construction to evaluate the damage and safety of buildings after strong earthquakes, facilitating decision-making during the emergency response phase on their habitability and reparability. A hybrid neuro-fuzzy system is proposed, based on a special three-layer feedforward artificial neural network and fuzzy rule bases. The inputs to the system are fuzzy sets, taking into account that the damage levels of the structural components are linguistic variables, defined by means of qualifications such as slight, moderate or severe, which are appropriate to handle subjective and incomplete information. The chapter is a contribution to the understanding of how soft computing applications, such as artificial neural networks and fuzzy sets, can be used to complex and urgent processes of engineering decision-making, like the building occupancy after a seismic disaster.
Abstract
This chapter describes the algorithmic basis of a computational intelligence technique, based on a neuro-fuzzy system, developed with the objective of assisting nonexpert [...]
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Seismic Evaluation of Low Rise RC Framed Building Designed According to Venezuelan Codes
J. Vielma, A. Barbat, R. Ugel, R. Herrera

(2013). Geotechnical and Structural Earthquake Engineering, INTECH, DOI: 10.5772/55158

Abstract
This chapter uses a mechanical method that involves non-linear analysis with deterministic and probabilistic approaches, as well as procedures of analysis based on limits states defined by displacements, in order to evaluate the behavior of a low rise RC building with plan irregularity designed according to Venezuelan codes and subjected to seismic actions. By using adequate structural models and computational tools, the seismic behavior of the building is obtained in a suitable way. Among these tools, the quadrants method was chosen, which provides the rapid assessment of the seismic capacity of a structure through its non-linear response. The results of the research show that the current design of this kind of structures is not safe when they are designed for the maximum seismic actions prescribed by codes. Therefore, it is necessary to review the design procedures in order to fulfill the goals of the performance-based design.
Abstract
This chapter uses a mechanical method that involves non-linear analysis with deterministic and probabilistic approaches, as well as procedures of analysis based on limits [...]
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Monte Carlo analysis of structural systems using neural networks
J. Hurtado, D. Álvarez, A. Barbat

(2001). MonteCarlo Simulation, Balkema, 265-271, ISBN: 90-5809-188-0

Abstract
Monte Carlo simulation is increasingly being used in the analysis of large and complex structural systems for the assessment of the uncertainty spread and the reliability. A major handicap for the popularization of this technology is the large number of deterministic evaluations needed to such purposes, inasmuch as linear or nonlinear finite element solvers are required for each output sample calculation. In order to simplify this task neural networks are evaluated in this paper as a partial surrogate of the deterministic solver. The neural networks are trained with the input/output pairs resulting from a few number of finite element simulations, and are henceforth used in a Monte Carlo context. It is shown that when employed in this way, neural networks constitute a promising tool for a drastic reduction of the computational cost needed by a Monte Carlo simulation in this field of application. Three types of networks have been selected for the study, two of which correspond to supervised and the other one to hybrid learning procedures. The paper compares the network designs in their more relevant aspects, which are the training speed and accuracy, the extrapolation ability and the accuracy of the estimated probabilities.
Abstract
Monte Carlo simulation is increasingly being used in the analysis of large and complex structural systems for the assessment of the uncertainty spread and the reliability. [...]
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Soil-structure-fluid seismic interaction
J. Miquel, A. Barbat

(2000). Estructuras sometidas a acciones dinámicas, CIMNE, 2000, 477-534, ISBN: 84-89925-68-2

Abstract
The behavior of structures subjected to earthquakes demonstrates that the phenomena of soil-structure and fluid-structure interaction have a great influence on the structural response, especially in the case of structures such as dams, tanks, elevated water tanks, marine platforms, intake towers, etc. The numerical study of these phenomena requires solving problems in which the coupling between two solids or between a solid and a fluid occurs only at the surfaces of contact between them. This chapter describes several numerical procedures used to solve the problem of seismic interaction. For this, it is necessary to have a record of seismic motion on the interface that separates the area of the soil considered in the analysis, which defines a theoretical surface sometimes called base rock. Below this, the soil can be assumed infinitely stiff or with a certain flexibility. To obtain an accelerogram at the level of the base rock, a deconvolution of the seismic motion available on the ground surface must be made. Then, this calculated accelerogram is applied on the soil-structure-fluid system.
Abstract
The behavior of structures subjected to earthquakes demonstrates that the phenomena of soil-structure and fluid-structure interaction have a great influence on the structural [...]
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Seismic risk of structures
O. Cardona, A. Barbat

(2000). Estructuras sometidas a acciones dinámicas, CIMNE, 2000, 369-397, ISBN: 84-89925-68-2

Abstract
From the perspective of disasters, risk has been defined in order to carry out its management, as well as to control the possible economic, social and environmental consequences that may occur in a specific area and time. This means that to estimate the risk it is necessary to take into account, from a multidisciplinary point of view, not only the expected physical damage, the victims or equivalent economic losses, but also social, organizational and institutional factors related to the development of the communities. At the urban level, for example, vulnerability, as an internal risk factor, must be related not only to the exposure of the material context or its physical susceptibility to being affected, but also to the social fragilities and the lack of resilience of the communities. In this chapter, conceptual, theoretical and practical problems related to seismic risk are presented. The definitions of hazard and seismic vulnerability, necessary to analyze the risk, are introduced. All the developments that are carried out are examined from the point of view of the possibilities of preventing seismic risk.
Abstract
From the perspective of disasters, risk has been defined in order to carry out its management, as well as to control the possible economic, social and environmental consequences [...]
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Nonlinear structural dynamics
B. Luccioni, S. Oller, A. Barbat

(2000). Estructuras sometidas a acciones dinámicas, CIMNE, 2000, 161-176, ISBN:84-89925-68-2

Abstract
When solving dynamic problems, it is necessary to define in some way the damping of the structure. Generally, a damping term that depends on the velocities is incorporated directly into the dynamic equilibrium equation. To do this, we define a structural damping matrix, such as Rayleigh's, which is quite difficult to estimate. Once the damping has been defined, the problem is solved as a linear elastic one, what enters in contradiction with the fact that a dissipative phenomenon is being treated. In this chapter, an alternative with greater conceptual basis is described, which considers the structural damping based on a viscoelastic constitutive models in which the stress depends in some way on the strain velocity. In this way, the term of structural damping arises directly in the dynamic equilibrium equation, where the properties of the materials can be determined through simple laboratory tests.
Abstract
When solving dynamic problems, it is necessary to define in some way the damping of the structure. Generally, a damping term that depends on the velocities is incorporated [...]
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Fundamenteal aspects of the seismic design codes
S. Oller, A. Barbat

(2000). Estructuras sometidas a acciones dinámicas, CIMNE, 2000, 145-160, ISBN: 84-89925-68-2

Abstract
The earthquake resistant design codes in force in the different countries are applied to the field of building structures. However, some of the standards give a certain appearance of "generality" that can give the impression that these are mandatory for any type of structure. In fact, the rules are general only in the definition of the seismic hazard of the area to which they apply, that is, in relation to the maximum ground acceleration. However, in each country, there are other specific codes for the design of non-building structures. This chapter describes the dynamic calculations foreseen in the building seismic design standards; the use of simplified, shear building models; the usual procedure of dynamic calculation of structures based on modal analysis; and, finally, the use of linear and non-linear response seismic spectra, which provides only the maximum response of the structure.
Abstract
The earthquake resistant design codes in force in the different countries are applied to the field of building structures. However, some of the standards give a certain appearance [...]
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La intensitat inversora de Catalunya i els mercats potencials de futur des de la perspectiva de la implantació
X. Mendoza Mayordomo

3r Congrés d'Economia i Empresa de Catalunya - Full papers.

Abstract
Esperonades per la profunditat de la crisi econòmica a Espanya i a la Unió Europea, les empreses catalanes han augmentat sensiblement la diversificació geogràfica de les seves implantacions internacionals. No obstant, cal esbrinar si l’esforç inversor i d’implantació s’està produint en destinacions (països i regions) que permetin aprofitar les dinàmiques de creixement en els mercats internacionals amb major potencial. Amb aquesta finalitat s’ha calculat i analitzat l’índex d’intensitat inversora de Catalunya per a 86 països i 10 regions mundials, i s’ha avaluat l’atractiu que presenten 105 països des de la perspectiva de la implantació. L’estudi conclou amb una proposta sobre les destinacions (països i regions) que presenten un major potencial de futur per a les implantacions de les empreses catalanes.
Abstract
Esperonades per la profunditat de la crisi econòmica a Espanya i a la Unió Europea, les empreses catalanes han augmentat sensiblement la diversificació [...]
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Computational simulation of the seismic response of buildings with energy dissipating devices
A. Barbat, P. Mata, S. Oller, J. Vielma

(2008). Computational structural dynamics and earthquake engineering, Taylor & Francis, ISBN978-0-415-45261-8, 255-274

Abstract
In this work, the nonlinear dynamic response of RC buildings with energy dissipating devices is studied using advanced computational techniques. A fully geometric and constitutive nonlinear model is used for describing the dynamic behavior of structures. The equations of motion are expressed in terms of cross sectional forces and strains and its weak form is solved using the displacement based finite element method. A suitable version of Newmark’s scheme is used in updating the kinematics variables in a classical Newton type iterative scheme. Material points of the cross section are assumed to be composed of several simple materials with their own constitutive laws. The mixing theory is used to treat the resulting composite. A specific finite element based on the beam theory is proposed for the dissipators including constitutive relations. Finally, several numerical tests are carried out to validate the proposed model.
Abstract
In this work, the nonlinear dynamic response of RC buildings with energy dissipating devices is studied using advanced computational techniques. A fully geometric and constitutive [...]
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PROBABILISTIC ASSESSMENT OF THE SEISMIC PERFORMANCE OF STEEL BUILDINGS DESIGNED ACCORDING TO THE LRFD SPECIFICATION
C. Bermúdez, J. Hurtado, L. Pujades, A. Barbat, J. González-Drigo

(2015). New trands in seismic design of structures, Saxe Coburg Publications

Abstract
Seismic regulations and building codes experienced major advances in the last decades. Nevertheless, current trends in earthquake engineering are the assessment of the computational procedures provided by such design rules, by using probabilistic techniques, in order to test the anticipated levels of reliability and performance of the structures. While some consideration is given in codes to the uncertainties associated to the seismic action, no probabilistic requirements are posed on the responses, which determine the final design. Consequently, the risk associated to the design formulas remains unknown. The objective of this chapter is to study whether steel buildings designed and constructed according to the Load and Resistance Factor Design (LRFD) specification for Structural Steel Buildings, reasonably meet the probabilistic requirements on structural member safety applying non-linear dynamic analyses and Monte-Carlo techniques. Starting from a specific low-rise braced frame steel building existing in Manizales, Colombia, we also analyze mid-rise and high-rise braced frame buildings. Similar low- mid- and high-rise Moment-resisting frame buildings are also studied. For each building we performed more than ten thousand dynamic simulations, covering a wide range of combinations of demand and strength. In this way, we determine the exceedance probability of the construction capacity and we verify the safety and reliability of the structural members of the buildings. In the analysis of demand, we consider the probabilistic variation of the vertical gravity loads as well as of the seismic horizontal ones. The analyses of the strength of the studied buildings take into account the uncertainties and probability distributions of several parameters as: the yielding strain, the elasticity modulus, the cross-sectional area and their inertia moments. The analysis shows that in the cases here analyzed, but especially in moment-resisting frame buildings, the uncertainties in the input parameters may lead to significant failure probabilities. We conclude that braced frame steel buildings fulfil the seismic safety requirements while moment-resisting frame buildings would require a safety factor of about 2.7 for the column anchorages to the foundations.
Abstract
Seismic regulations and building codes experienced major advances in the last decades. Nevertheless, current trends in earthquake engineering are the assessment of the computational [...]
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Evaluation of the seismic hazard of Barcelona and its application to the estimation of the seismic risk of the city
A. Aguilar, L. Pujades, A. Barbat, M. Ordaz, N. Lantada

(2015). Metodologías aplicadas a las Ciencias de la Tierra

Abstract
In the present work, the main steps used in the probabilistic estimation of the seismic hazard of the city of Barcelona, Spain, are described, and it is mentioned how the hazard was used in the probabilistic estimation of the seismic risk of the city. For comparative purposes, the seismic hazard of Barcelona was estimated both in terms of exceedance rate of the macroseismic intensities, and in terms of exceedance rate of the maximum ground acceleration (PGA). In the estimation, the computer code CRISIS2008 (Ordaz et al., 2008) was used, which is based on the methodology proposed by Cornell (1968) and Esteva (1970). This code incorporates valuable tools that allow estimates of seismic hazards to be made at an important level of detail. According to the results, in Barcelona, the PGA value equal to 85 cm/s2, has an average return period of 475 years. The results obtained in terms of macroseismic intensities, indicate that the intensity that has an average a return period of 475 years corresponds to a value between VI and VII. The seismic hazard curves in terms of macroseismic exceedance rates were obtained with the aim of being used in the estimation of the seismic risk of the city by means of the probabilistic method of vulnerability indices (Aguilar, 2011). According to the results, in the city there are buildings with a high level of seismic risk. This is because, despite the fact that Barcelona is located in a zone of low to moderate seismicity, there is a significant percentage of buildings with significantly high levels of seismic vulnerability. The seismic risk curves obtained are expressed in terms of exceedance frequencies of the degrees of seismic damage.
Abstract
In the present work, the main steps used in the probabilistic estimation of the seismic hazard of the city of Barcelona, Spain, are described, and it is mentioned how [...]
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Analysis of an experimental composited joint of RC column and beams-steel column for frames using correlation of digital images
N. López, R. Ugel, R. Herrera

Gaceta Técnica (2018). Vol. 19 (1), 3

Abstract
This research presents the behavior of a real scale experimental column-beam joint formed by three reinforced concrete elements, 1 column and 2 beams, attached to a structural steel column in the upper level is studied. The specimen in question was subjected to the action of cyclic loads in a single direction, in a pseudostatic test for 5000 s, in order to observe which element of the specimen failed and which the failure mode was. The investigation was based on the use of digital images taken throughout the test, during the loading and unloading cycles, each photo being analyzed with the CORRELI-Q4 subroutine, in order to visualize the places where cracking occurs in the concrete. The use of the application allowed to reveal how cracking in the reinforced concrete occurred during the test, and that the column of reinforced concrete was the one that was most affected by cracking, with cracks just below the concrete beams.
Abstract
This research presents the behavior of a real scale experimental column-beam joint formed by three reinforced concrete elements, 1 column and 2 beams, attached to a structural [...]
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Economic and Political Globalization
J. Minoves, S. Content

3r Congrés d'Economia i Empresa de Catalunya - Full papers.

Abstract
This paper surveys opposing interpretations of globalization of the late twentieth and early twenty-first century. Since there are multiple definitions of globalization it focuses mainly on economic globalization and political globalization. It argues that the economic benefits of globalization are not evenly distributed, with China being among the winners within the developing world. Unskilled workers in the de-industrializing developed nations are among the losers; they fuel protectionist political discourses and have helped Trump become the US President. This paper also argues that in a globalized world liberal democracy has two main competitors as ideal types of political regimes, namely Chinese market-oriented authoritarianism and Russian/Turkish style illiberalism. This paper also reasserts the prevalence of the State. Nationalist movements in Europe, such as the ones in Scotland or Catalonia, desire their own states for reasons that are not alien to globalization. Also the State seems to be the necessary instrument to fight effectively against the main negative effects of economic globalization: climate change and the destruction of the environment.
Abstract
This paper surveys opposing interpretations of globalization of the late twentieth and early twenty-first century. Since there are multiple definitions of globalization it [...]
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Numerical modelling of railway ballast behaviour using the Discrete Element Method (DEM) and spherical particles
J. Irazábal González, F. Salazar, E. Oñate

(2015). IV International Conference on Particle-Based Methods. Fundamentals and Applications (PARTICLES 2015)

Abstract
In the last two decades there has been a great development of high-speed train lines. This advance has led to more demanding loads in railway infrastructures and the appearance of a new problem called ballast flight that happens when some stones rise when the train passes. For these reasons, the development of an application that allows the numerical modelling of the ballast superstructure under different stresses can be very useful, as it will enable design optimization. The DEM is being considered an effective and powerful method for the calculation of engineering problems with granular and discontinuous materials. Railroad ballast layer consists of discrete aggregate particles, so that DEM is one of the most suitable ways to simulate the behavior of particulate ballast material. However, the computational cost of contact calculation between irregular particles is high and limits the calculation capability. From the point of view of micro-scale analysis, it is essential to represent the exact geometry of the particle. On the other hand, if the interest lies in the behavior of the granular material as a whole, the geometry is not a determining factor. Besides that, setting up a simulation of granular material taking care of the exact geometry of each particle will not be efficient. Current work presents the methodology followed to achieve accurate results in the calculation of railway ballast behaviour using DEM and spherical particles. The use of spherical particles reduces the computational cost and makes the simulation set up efficient. Validation results for the calculation of the lateral resistance force against a sleeper moving inside a ballast bed are presented. Regarding ballast flight problem, some high speed ballast collision calculations have also been performed.
Abstract
In the last two decades there has been a great development of high-speed train lines. This advance has led to more demanding loads in railway infrastructures and the appearance [...]
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Numerical modelling of landslides in reservoirs using the particle finite element method and a non Newtonian Bingham model
J. Irazábal González, F. Salazar, E. Oñate

(2013). III International Conference on Particle-Based Methods. Fundamentals and Applications (PARTICLES 2013)

Abstract
Landslides in reservoirs constitute one of the main threats to dams. Although they are not frequent, they may generate severe damages in the population and goods placed near the shores. It is a complex phenomenon, because of the interaction between the landslide, the still water in the reservoir, and the dam. The Particle Finite Element Method (PFEM) is an innovative numerical scheme which combines a lagrangian approach with the resolution of FEM equations via mesh generation. In previous works, it had been applied to the simulation of landslides in reservoirs, considering the moving body either as a rigid solid or as a Newtonian fluid. Despite the promising results of the simulation of some reference cases, these constitutive models showed poor performance when applied to other relevant events, such as Vaiont case. Current work introduces the implementation of a non Newtonian Bingham model in the particle finite element method scheme, and the results of its application to several benchmark cases. Some of them have been used to calibrate the parameters of the Bingham model, whereas others served as test cases. The phenomenon presents several intrinsic uncertainties, such as the lack of precise information about the physical properties of the landslide, its geometry, its granulometry, the drag coefficient along the sliding surface, among others. In spite of that, results show that the Bingham model implemented can be useful for estimating the potential consequences of landslides in reservoirs. This implementation makes the PFEM a versatile numerical tool for the analysis of landslides in reservoirs, provided that from now on both rigid solids, Newtonian and non Newtonian fluids can be accounted for. The authors are currently working in the optimization of the numerical code, so that more complex problems could be afforded in more detail. In addition, the erosion module is being validated, in order to reproduce effects such as the dragging of the underlying material due to the landslide, as well as the effect of overtopping on dam stability, particularly for rockfill dams.
Abstract
Landslides in reservoirs constitute one of the main threats to dams. Although they are not frequent, they may generate severe damages in the population and goods placed near [...]
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Scenarios of seismic impact
L. Pujades, A. Barbat

(2009). Terremotos, CSIC

Abstract
In this chapter, the concept of seismic risk is introduced and a review of its historical evolution is made. The number of seismic catastrophes has also been increasing in the twentieth century while the number of earthquakes with destructive capacity remains constant. This must be correlated with the growth of the world's population and with the increasing extension of urban areas in the seismic regions of the world. In these areas, coexist buildings designed by applying advanced standards, with old buildings, without any seismic design. There are also more and more catastrophes of another origin, related to storms, floods, droughts, effects of human activity on the environment, etc. It is very relevant that the increase in seismic risk occurs in the conditions in which seismic standards are continuously improving in all countries. Finally, the authors introduce the concept of seismic scenario and show examples of application for the city of Barcelona, Spain.
Abstract
In this chapter, the concept of seismic risk is introduced and a review of its historical evolution is made. The number of seismic catastrophes has also been increasing in [...]
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Editorial: Evitar el plagio. Respetar la autoría
L. Casadei

Gaceta Técnica (2018). Vol. 19 (1), 1

Abstract
EDITORIAL: EVITAR EL PLAGIO. RESPETAR LA AUTORIA
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Confinement and ductility of reinforced concrete buildings
J. Vielma, A. Barbat, S. Oller

Alex Barbat's monographs (2018). 25

Abstract
This monograph focuses on an eminently practical issue, which allows to take advantage of the characteristics associated with high ductility steels: the confinement of concrete. An adequate disposition, not only of the transversal reinforcement, but also of the longitudinal reinforcement itself, can considerably increase the performance of the structures. This fact is something fundamental when the structures are subjected to actions close to the collapse situations, as it happens in the case of some earthquakes. Given the importance of this last aspect, as well as the increasing importance that issues related to the earthquake are beginning to have in Spain, this monograph analyzes which are the most appropriate structural typologies in these situations, and what is the contribution of high ductility steel to the improvement of its behavior. The result does not shows excessive surprises. The structurally "more robust" typologies are those constituted by moment resisting frames, consisting of a network of beams and columns. Other typologies, commonly used in our country, such as the structures with columns and slabs, or with flat beams, remain on the side of insecurity. The contribution of high ductility steels is very favorable in the case of the appropriate typologies, while it is insufficient to resolve the bad seismic behaviour of the "more sensitive" typologies.
Abstract
This monograph focuses on an eminently practical issue, which allows to take advantage of the characteristics associated with high ductility steels: the confinement of concrete. [...]
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La contribució d’una gestió eficient dels residus al foment de l’economia circular
J. Tost

3r Congrés d'Economia i Empresa de Catalunya - Full papers.

Abstract
L'economia circular és un model econòmic i productiu que estableix que qualsevol residu és un recurs. Aplicant les seves bases, aconseguim: * Millorar els resultats econòmics reduint l'ús dels recursos * Identificar i crear noves oportunitats de creixement econòmic * Garantir la seguretat del subministrament de recursos essencials * Lluitar contra el canvi climàtic (un 3% del factor climàtic té a veure amb la gestió de residus) A Catalunya s’ha plantejat un horitzó del 60% de recollida selectiva per a 2020 i, tenint en compte que actualment s’està en el 38% de, cal avançar en les estratègies per millorar aquests resultats. Les administracions, les empreses i la societat en general són claus per tal d’assolir un circularitat dels residus com a recursos. A partir del darrer quart del segle XX, a mida que la societat ha anat prenent consciència que determinades pràctiques acabaven tenint un efecte bumerang negatiu, és quan s’ha començat a articular un discurs i a adoptar unes mesures que perseguien en primera instància minorar aquests impactes sobre el medi i les persones; és aquí quan s’abandona la gestió “incontrolada” per passar a la gestió “controlada” dels residus. Ara, però, estem immersos en un nou punt d’inflexió: els residus ja no són un element molest del què cal desfer-se: són un recurs i una oportunitat de generar activitat econòmica i llocs de treball. Ja no és realista pensar en escenaris infinits de primeres matèries. Tenim la certesa que, cada vegada amb més evidència, els recursos naturals entraran en escenaris d’escassetat creixent i els residus, si no són malbaratats, poden esdevenir una font important d’obtenció de nous recursos. Els residus generats per les activitats s'han de gestionar per minimitzar els impactes negatius sobre el medi ambient i la salut humana. Així, a més de prevenir els efectes més nocius i indesitjables, des del punt de vista del medi ambient, també s'ha de promoure el seu valor com a recurs per a la producció de materials que es poden integrar de nou en els processos de producció, per tal d'avançar efectivament cap a un economia circular. Hem d’entendre, per tant, la gestió dels residus en tant que sector econòmic i potencial generador d’oportunitats, de negoci i laborals. A Catalunya gaudim d’una trajectòria extensa en gestió de les deixalles. El 1993 va néixer la primera llei reguladora de residus, que ens va situar a tots sobre unes bases modernes i eficaces en la seva gestió, i on va començar el que podríem dir-ne la planificació moderna. Transcorreguts aquests 20 anys, ara hem d’entrar en una etapa nova, en la que el context econòmic dels darrers anys ens ha fet també pensar en com hem d’avançar amb més eficàcia, però també amb optimització econòmica. Cal pensar que l’escenari infinit de primeres matèries ja no és aquest, cada vegada els recursos entraran en escenaris d’escassetat, i els residus poden ser una font contributiva en aquest escenari.
Abstract
L'economia circular és un model econòmic i productiu que estableix que qualsevol residu és un recurs. Aplicant les seves bases, aconseguim: * Millorar [...]
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Probabilistic seismic hazard and risk assessment in Spain
M. Salgado-Gálvez, O. Cardona, M. Carreño, A. Barbat

Monograph Series in Earthquake Engineering, editor A. H. Barbat (2015). MIS69, ISBN: 978-84-943307-7-3

Abstract
This monograph explains how probabilistic seismic risk assessments can be performed at different resolution levels using the same methodology, providing results in terms of the same metrics; but it also highlights what the differences in terms of inputs for the analysis are in the different cases. A country level assessment is first performed using a coarsegrain exposure database that includes only the building stock in the urban regions of Spain. A detailed urban seismic risk assessment is performed for Lorca, Murcia, Spain. In both cases, the fully probabilistic seismic risk results are expressed in terms of the loss exceedance curve, which is the main output, from where different probabilistic risk metrics, such as the average annual loss and the probable maximum loss can be derived. Because of the damage data availability for the Lorca, May 2011, earthquake, a comparison between the observed losses and those modelled using an earthquake scenario with similar characteristics in terms of location, magnitude and spectral accelerations was done for the building stock of the city. The results of the comparison are presented in terms of expected losses (in monetary terms) and damage levels related to the obtained mean damage ratios are compared with those observed by post-earthquake surveys. This monograph is an effort to explain, in a transparent and comprehensive way, through a step by step example, how risk can be calculated in probabilistic terms and what are the influences of the inputs in each of the stages and what the obtained results mean. After reviewing several available tools to estimate catastrophe risk by means of probabilistic approaches, the CAPRA Platform was chosen because its flexibility, compatibility with the assessments to be performed at different resolution levels and its open-source/freeware characteristics.
Abstract
This monograph explains how probabilistic seismic risk assessments can be performed at different resolution levels using the same methodology, providing results in terms of [...]
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Earthquake resistant design of framed structures
J. Vielma, A. Barbat, S. Oller

Monograph Series in Earthquake Engineering, editor A. H. Barbat (2011). MIS65, ISBN: 978-84-95999-60-3

Abstract
The monograph begins with a review of the usual seismic analysis procedures and presents the problem of seismic-resistant projects. The required structurual analyses can be elastic or inelastic, but the latter have been used mostly during the last decade thanks to advances in numerical methods and in the area of computers. It also presents a summary of the most common seismic codes prescriptions for reinforced concrete elements and examines aspects of conceptual design that often come from code recommendations. Next, an introduction to the theme of performance based design is made. A method for linear seismic dimensioning is then developed, but with displacement amplification factors obtained from research performed on the nonlinear behavior of the structures. This method allows the displacements, and not the strength, to govern the project, is simple to apply, compatible with most of the rules required by the earthquake resistant structures and is illustrated by the application to a group of reinforced concrete framed buildings. Once the buildings designed, they be subjected to seismic actions of the pseudostatic or dynamic type and will undergo a non-linear behaviour. The response of the structures is evaluated by applying a set of limit states formulated in accordance with the principles of performance based design. The non-linear response allows to calibrate some of the factors applied in the seismic project, such as the global ductility, the behavior factor and the redundancy factor and resistance reserve. From the non-linear response, damage indices are obtained, both local and global, that allow the rapid evaluation of the seismic behavior, as well as the identification of the areas in which the damage is concentrated and which must be reinforced. Finally, using a series of thresholds that allow the definition of the limit states, a mixed procedure (deterministic-probabilistic) is applied by means of which the exceedance probabilities of the mentioned states are calculated. These procedure allows calculating fragility curves and damage probability matrices that applied according to the conceptual framework of the performance based design, allow obtaining earthquake resistant buildings.
Abstract
The monograph begins with a review of the usual seismic analysis procedures and presents the problem of seismic-resistant projects. The required structurual analyses can be [...]
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The fiscal risk management from the perspective of disasters
M. Marulanda, O. Cardona, M. Ordaz, A. Barbat

Monograph Series in Earthquake Engineering, editor A. H. Barbat (2008). MIS61, ISBN: 978-84-96736-60-3

Abstract
This monograph presents a summary of the importance for the State of having a public policy of protection or financial management of risk from the perspective of disasters. Reference is made to the legal and fiscal responsibility, to the obligations and contingent liabilities that represent, implicitly, disasters for the State. And, also, reference is made to the implications of not having a well-defined “ex ante” policy from the financial point of view for a country prone to disasters of different kinds and, in general, against catastrophic risk. A succint description of the Disaster Deficit Index, IDD, is then made, whuch provides macroeconomic and financial authorities with access, in appropriate terms, to relevant information on disaster risk at the national or subnational level. This indicator allows to dimension the fiscal exposure and the potential deficit - which are contingent liabilities - of the country in a simple way and to identify and propose possible policies and effective actions of financial protection of the State. Likewise, it shows the impact caused by recurrent minor disasters that cause a significant social and environmental risk in the countries. Finally, the basic concepts about the traditional role of the insurance and reinsurance industry and other financial schemes used or that could be explored to integrate them into the integral risk management are presented.
Abstract
This monograph presents a summary of the importance for the State of having a public policy of protection or financial management of risk from the perspective of disasters. [...]
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Ineslatic analysis of geometrically exact rods
P. Mata, A. Barbat, S. Oller, R. Boroschek

Monograph Series in Earthquake Engineering, editor A. H. Barbat (2008). MIS60, ISBN: 978-84-96736-59-7

Abstract
In this work, a formulation for rod structures, able to consider coupled geometric and constitutive sources of nonlinearity in both the static and the dynamic range, is developed. It is extended for allowing the inclusion of passive energy dissipating elements as a special rod element and geometric irregularities as a full three-dimensional body connected to the framed structure by means of a two-scale model. The proposed formulation is based on the Reissner-Simo geometrically exact formulation for rods considering an initially curved reference configuration and extended to include arbitrary distribution of composite materials in the cross sections. Each material point of the cross section is assumed to be composed of several simple materials with their own thermodynamically consistent constitutive laws. The simple mixing rule is used for treating the resulting composite. Cross sections are meshed into a grid of quadrilaterals, each of them corresponding to a fiber directed along the axis of the beam. A mesh independent response is obtained by means of the regularization of the energy dissipated at constitutive level considering the characteristic length of the mesh and the fracture energy of the materials. Local and global damage indices have been developed based on the ratio between the visco-elastic and nonlinear stresses. The consistent linearization of the weak form of the momentum balance equations is performed considering the effects of rate dependent inelasticity. Due to the fact that the deformation map belongs to a nonlinear manifold, an appropriated version of Newmark's scheme and of the iterative updating procedure of the involved variables is developed. The space discretization of the linearized problem is performed using the standard Galerkin finite element approach. A Newton-Raphson type of iterative scheme is used for the step-by-step solution of the discrete problem. A specific element for energy dissipating devices is developed, based on the rod model but releasing the rotational degrees of freedom. Appropriated constitutive relations are given for a wide variety of possible dissipative mechanisms. Several numerical examples have been included for the validation of the proposed formulation. The examples include elastic and inelastic finite deformation response of framed structures with initially straight and curved beams. Comparisons with existing literature is performed for the case of plasticity and new results are presented for degrading and composite materials. Those examples show how the present formulation is able to capture different complex mechanical phenomena such as the uncoupling of the dynamic response from resonance due to inelastic incursions and suppression of the high frequency content. The study of realistic flexible pre-cast and cast in place reinforced concrete framed structures subjected to static and dynamic actions is also carried out. Detailed studies regarding to the evolution of local damage indices, energy dissipation and ductility demands are presented. The studies include the seismic response of concrete structures with energy dissipating devices. Advantages of the use of passive control are verified.
Abstract
In this work, a formulation for rod structures, able to consider coupled geometric and constitutive sources of nonlinearity in both the static and the dynamic range, is developed. [...]
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Tools necessary for the seismic evaluation of buildings
R. González, L. Pujades, A. Aparicio, A. Barbat

Monograph Series in Earthquake Engineering, editor A. H. Barbat (2007). MIS59, ISBN: 978-84-96736-53-5

Abstract
This monograph presents the fundamental concepts related to seismic action, the structural response of buildings, the assessment of vulnerability, risk and seismic damage. Some indices proposed by different researchers are also indicated to assess the level of damage suffered by buildings under seismic actions. It also describes the ways to define the seismic action that are appropriate to the structural analysis. Techniques are developed to generate artificial accelerograms, which are necessary to perform the evaluation of the non-linear seismic response through an analysis in time. This evaluation also allows obtaining the level of damage suffered by the structures. The seismic action is focused on the city of Barcelona, Spain, which is located in an area of moderate seismicity and, in addition, does not have seismic records. The seismic action is established by seismic design spectra and artificial accelerograms compatible with said spectra. At the end of this work, the responses spectra considered to define the seismic demand and the artificial accelerograms obtained are shown, which can be used for the evaluation of structures for different seismic intensities and for different locations in Barcelona. Finally, a methodology for assessing the vulnerability and the seismic risk of buildings is described. The methodology is applied in several steps and includes modeling and non-linear analysis of structures. It is focused on obtaining fragility curves, which can be generated both through an empirical evaluation and through an analytical evaluation. The first is based on the damage observed in the buildings of an area after an earthquake occurs, while the second is based on a numerical analysis, where the seismic response of the structure is predicted.
Abstract
This monograph presents the fundamental concepts related to seismic action, the structural response of buildings, the assessment of vulnerability, risk and seismic damage. [...]
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