CMMoST 2015. International Conference on Mechanical Model in Structural Engineering (3rd. 2015. Sevilla)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/34627

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Use of TMD in structural engineering: Building Parque Araucano in Santiago de Chile
(Víctor Compán Cardiel [etc.], 2015) Breschi, L.; Castillo, A.
The application of Tuned Mass Dampers in mechanical engineering is of longstanding and habitual use. In these kinds of applications, the loading forces are based on constant frequencies and they are in most case well known. The application of a TMD in structural engineering is more recent, beginning a few years ago under the concept of seismic protection. The design of a TMD for a building presents the practical difficulty of tuning the device to the fundamental period of the structure. Through the application of additional damping, it is possible to widen the range of tuning frequencies and therefore increase the effectiveness of the TMD. Additionally, the seismic loads to which the structure will be submitted are uncertain in their frequency distribution which could generate a counterproductive effect, because the response of the building to the seismic forces could be even worse with the use of TMD. The addition of more damping has the result of a reduction of the positive effect of the TMD at the fundamental frequency, but produces a better response for the entire range of frequencies of the seismic excitation. The following work shows both the theoretical and practical application of this concept to a building built in 2006 in Santiago de Chile, which passed unscathed the 2010 Maule Earthquake, which reached a magnitude 8,8 Mw with an intensity VIII in the locations of the building.
Upper bound to the effective area of concrete in tension
(Víctor Compán Cardiel [etc.], 2015) Gil Martín, L.M.; Carbonell-Márquez, J. F.; Hernández-Montes, Enrique
The effective tension area of concrete is a well known parameter in structural concrete. It is involved in several phenomena that affect the design of structural concrete elements, such as cracking, shear deformation or flexural deformation. In this work, the authors put forward a necessary change in the definition of the effective tension area of concrete provided by some groups of Standards.
Towards a unified mechanical model for design and assessment of structural concrete members under shear, flexure and punching
(Víctor Compán Cardiel [etc.], 2015) Marí, Antonio; Cladera, Antoni; Bairán, Jesús; Oller, Eva
A mechanical shear model for structural concrete members with and without stirrups is presented, which incorporates the most relevant shear transfer mechanisms. The model is based on the principles of structural mechanics, on a number of assumptions supported by the observed experimental behaviour and by the results of refined numerical models. Simple, direct and robust expressions are derived for shear strength verification and for design of the transverse reinforcement. The general theory behind the model enables it for steel or FRP simply supported or continuous, reinforced or prestressed concrete members, with any cross section, subjected to distributed and point loads or to axial forces. Excellent agreement between the results of a large number of shear tests and the model predictions has been obtained. The model is currently being extended to punching of slabs, for which the critical perimeter is obtained as a result of the model formulation
The evolution of structural engineering education in the era of computer
(Víctor Compán Cardiel [etc.], 2015) Vázquez-Boza, Manuel; Justo Moscardó, Enrique de; Delgado Trujillo, Antonio; Universidad de Sevilla. Departamento de Estructuras de Edificación e Ingeniería del Terreno
In the last decades, the universalization of computer analysis has meant a revolution in the structural analysis methods that are being used in the professional practice. As a consequence, the need has arisen both in academic and professional circles to redefine the teaching of structures in the engineering and architecture schools. This study analyses, in the first place, the literature on structural analysis teaching to synthesize the characteristics that should have a structural analysis course in the context of the XXI century. Starting from the analysis of shortcomings in the current teaching, a panorama on future directions in the teaching of structures is outlined, in relation to the objectives, the contents, the instructional method, the use of computer and the role of hand calculation. The literature revision allowed establishing a theoretical framework for the design of a structures course syllabus adapted to the present needs. In general, it is assumed that the universalization of computer analysis should lead to a paradigm shift in the teaching of structures. Instead of focusing in learning hand analysis methods, the structures courses should be aimed at the understanding of the structural behavior, which is required to carry out successfully the tasks that the graduates should undertake in their professional practice. Finally, we present an experience carried out in the Seville School of Architecture, where a course based in the principles outlined in the literature and also following the guidelines of the European Higher Education Area (EHEA) has been designed and implemented. The program evaluation has yielded positive results, which include a significant increase in the attendance and success rate.
The implementation of the new technologies for advanced graphic expression in studies conducted using structural graphical statics and its comparison with architectural treatises of the time
(Víctor Compán Cardiel [etc.], 2015) Garfella Rubio, José Teodoro; Mañez Pitarch, María Jesús; Martínez Moya, Joaquín Ángel
Technological evolution has brought us new methods of analysing and studying historical architectural buildings by means of advanced graphic documentation and the use of high definition resources such as the laser scanner and the architectural photogrammetry. The application of these systems and equipment has made it possible to graphically document a number of buildings with a certain degree of thoroughness and precision, while optimising the available resources and the time required for data collection. At the same time, the need for auxiliary devices has been reduced and reliable results have been obtained at a lower cost. Once the necessary graphic documentation has been obtained, it can been used to construct a reverse architectural model, and digital methods will then be implemented in order to apply the structural criteria of the era in which the building was constructed. This entire process will be carried out by means of graphic methods, or what is known as graphical statics, and the results will be compared. The results thus obtained can then be compared with a series of architectural treatises of the time. In this particular case, the studies involved several examples of religious architecture constructed in the early 17th century, in the province of Castellon, Spain, and their stability and approximation have been tested by graphical statics methods applied to advanced graphical documentation by comparing them with the treatises of the time (Rodrigo Gil de Hontañón by Simon Garcia, Hernan Ruiz the younger and Blondel) and the stability of the temple itself (Kooharian - Heyman).
The elastic view of the structural continuum versus the strength of material analysis
(Víctor Compán Cardiel [etc.], 2015) López-Rey, Javier; Ripoll, Salomé
The appearance of the graphic computing has allowed to deal with analysis of two and threedimensional structural continuum by means of mechanic models that have the capacity to understand the simplest and more complex behaviors between local geometries that classic methodologies are not able to describe. This fact involves the re-adoption of the Elasticity Theory and the prominence of the stresses against the comfortable view to simplify them along one of the geometry dimensions (e.g. one of the beam edges) to convert them into strains. The Strength of Materials concepts and the vectorial calculus might become outdated nowadays. Moreover, the Finite Element Method used in this study allows facing structural geometries with geometric and functional complexity. This would not be possible with classic methods without introducing important simplifications.
Structural analysis of a deployable double-layer tensegrity grid
(Víctor Compán Cardiel [etc.], 2015) Gómez-Jáuregui, Valentín; Sánchez Haro, Javier; Manchado, Cristina; Otero, César
Different methods have been used recently to discover new families of a type of space frame: Double- Layer Tensegrity Grids (DLTGs). The main objective of this work is analyzing the process for the design and calculation of a specific deployable DLTG (DDLTG) at full scale (4x4x1 m) composed by 16 modules of 1x1x1 m. Three CAD/CAE tools were used for these purposes: ToyGL, Matlab/Octave, and Midas Civil. It was necessary to create an intermediate platform to exchange data and information between both tools, the ToyGL Processor, based on user-defined functions written in VBA for Microsoft Excel. The methodology was validated by comparing the results obtained by the first two software tools with those provided by Midas Civil. As a conclusion, ToyGL is reliable and accurate in terms of the definition of geometry, distribution of stresses and forces, reactions, states of self-stress, mechanisms, etc.
Steel structure in Logroño bus station project
(Víctor Compán Cardiel [etc.], 2015) García Manzanos, Miguel
The steel structure of the future bus station Logroño fits within unique structures and architecturally representative buildings. This structure is part of an urban complex that allows integration railroad passing through Logroño (being already built its first phase ‐Railway Station‐). This structure is substantially symmetrical from the previously executed, and includes a central dome which gives pedestrian continuation over the park located on both stations. The problem set out is to generate a resistant structure put in place between two unrelated to the resistant form surfaces (the upper urban park and the interior finishes station). The tridimensional geometric design, complexity of model and measuring process (the high number of load paths under consideration) are factors that attribute an extra value to the structure and affirm their uniqueness.
Static, modal and dynamic behaviour of a stress ribbon footbridge : experimental and computational results
(Víctor Compán Cardiel [etc.], 2015) Castaño, Javier; Cosido, Oscar; Pereda, José; Cacho-Pérez, M.; Lorenzana, Antolín
Response for the static, modal and dynamic problem corresponding to a stress ribbon footbridge is studied. The equilibrium equations describing the problem are coupled nonlinear differential equations which are numerically solved using the finite element method. The objective of this work is to present a proper computational model for such a structure and to check its applicability in predicting not only the static behaviour but also modal parameters and estimate its dynamic response. As the footbridge is continuously monitored, it has been possible to measure the sag and to identify natural modes. This experimental data has been used for updating the finite element model.
Sliding collapse in masonry structures : experimental tests
(Víctor Compán Cardiel [etc.], 2015) Magdalena, Fernando; Aznar López, Antonio; Hernando, José Ignacio; Magdalena, Eva
Thirty-three static load tests were carried out in dry masonry walls. These walls have been subjected to their self-weight and to a horizontal load to promote a sliding failure between the blocks. The point of application of the load has been unchanged. All the walls have been constructed with the same ninety eight blocks. The disposition of the blocks have been done randomly in each of the walls to place the imperfections randomly too. The two objectives of this work have been: firstly, to obtain plenty of sliding tests which could enable to form a statistical judgment of the results, and secondly, to compare them with the results from several numerical methods commonly used, especially with the non Standard Limit Analysis (nSLA) ones.
Sliding collapse in masonry structures : a numerical model
(Víctor Compán Cardiel [etc.], 2015) Magdalena, Fernando; Hernando, José Ignacio; Magdalena, Eva
A probabilistic Non-Standard Limit Analysis based method is proposed to do safety assessments of historical masonry structures when collapse develops under sliding movements. The problem is presented as an Unilateral Contact Problem, formulated as a Complementarity Problem and solved as a Sequential Linear Programming with random starting points. The implemented method is a Monte Carlo type method that consists in: 1) fixing random points of application; 2) calculating the maximum value of the point load by Linear Programming; 3) making sure that the solution is in the onset of collapse; 4) rejecting the solutions that do not meet the requirements; 5) calculating the minimum value of the point load that would promote the collapse while keeping the same values of the limit conditions. The results are compared with a set of thirty three sliding tests carried out on dry masonry walls.
Serviceability conditions of pedestrian structures using a simplified moving mass model
(Víctor Compán Cardiel [etc.], 2015) Magdaleno, A.; Cacho-Pérez, M.; Castaño, Javier; Ibán, Norberto; Díaz, Iván M.; Lorenzana, Antolín
A simple mechanical model for pedestrian loading, consisting on a mass with a single degree of freedom that moves at constant speed along the footbridge, is presented. The footbrigde is modelled using a reduced number of beam 2D finite elements, simply supported at its ends. The dynamic interaction is ensured through direct requirement of contact conditions between the mass and the corresponding interpolated point in the beam. When the beam is massive enought, the results are similar to those obtained with models of mobile forces. However, if the beam is lightweight, the effect of the mass of the pedestrian can be significant, resulting in a more realistic modelling. The coupled model allows to study the interaction between the pedestrian and the structure and the results can be used to estimate by simulation the serviceability conditions of this type of slender structures under pedestrian loading.
Self-control of a lively footbridge under pedestrian flow
(Víctor Compán Cardiel [etc.], 2015) Hernández-Díaz, Alejandro M.; Pérez-Aracil, Jorge; Jiménez Alonso, Javier Fernando; Sáez Pérez, Andrés; Universidad de Sevilla. Departamento de Estructuras de Edificación e Ingeniería del Terreno; Universidad de Sevilla. Departamento de Mecánica de Medios Continuos y Teoría de Estructuras
In this paper, a case study about a lively footbridge is developed; the vibration levels caused by the pedestrian action are controlled by the change of the modal parameters of the structure due to the pedestrian-structure interaction. A detailed finite element model of the structure has been updated from an operational modal analysis. The updated model has been used to obtain the numerical acceleration at the mid-span of the footbridge under different pedestrian flows. A relation between the maximum acceleration and the pedestrian density on the deck has been obtained numerically, pointing out an improvement in the comfort level of the structure when the number of pedestrians increases. This result validates a design rule for cable-stayed footbridges in order to avoid vibratory problems, since the first vertical natural frequency of the structure remains below the range that characterizes the pedestrian walking action.
Replacement of cables of the cover archs carbon park in As Pontes (A Coruña)
(Víctor Compán Cardiel [etc.], 2015) Santamarta Martínez, Jaime; Alonso Raso, Jose Ignacio
The work done by Acciona Engineering at the coal yard located in As Pontes, is included within the maintenance plan established by Endesa for the period 2010-2020. This consists of predictive, preventive and corrective actions on the cables of the roof structure, which ultimately will allow extending the useful life of the facilities of the power plant. Several pathologies were detected in numerous cables, and in particular, “cable 15 of arch ner15", suffered an advanced state of degradation with significant loss of its resistant section. This led to recommend its replacement, for which an engineering detail design project was carried out. Therefore, a structural model of the whole arch affected by the pathology was done to allow the analysis of the structural behaviour of the cover during the replacement of the cable. To achieve this goal, the model was performed by implementing a three-dimensional system of nodes and bars processed with GtStrudl structures software.
Reliability-based optimization of steel structures using genetic algorithms and nonlinear finite elements
(Víctor Compán Cardiel [etc.], 2015) Celorrio Barragué, Luis
Uncertainties are inherent in material properties, geometry parameters and loading in structural design problems. In a realistic design, it is necessary to consider these types of uncertainties to ensure safety and quality. Design constraints are formulated in probabilistic terms such as probability of failure or reliability index. The process of design optimization enhanced by the addition of reliability constraints is referred as Reliability-Based Design Optimization (RBDO). Most of RBDO methods use classical mathematical optimization algorithms and require the gradients of objective function and constraints. This task sometimes can be cumbersome and hard because reliability constraints are implicit functions of design variables. However, the increased power of computers has made possible to apply heuristic methods, especially Genetic Algorithms in RBDO problems. In this paper Genetic Algorithm is combined with OpenSees, a nonlinear Finite Element Reliability Analysis software, to salve RBDO problems. Two numerical examples show the performance of the implementation.
Relevant features in steel structures teaching in building construction by project-based learning
(Víctor Compán Cardiel [etc.], 2015) Delgado Trujillo, Antonio; Justo Moscardó, Enrique de; Molina Huelva, Marta; Rodríguez-Mayorga, Esperanza; Universidad de Sevilla. Departamento de Estructuras de Edificación e Ingeniería del Terreno; Universidad de Sevilla. Departamento de Mecánica de Medios Continuos y Teoría de Estructuras
New approaches to teaching are moving towards a learning ever more active, practical and closer to professional sector, and have converged in a competence based education proposed by the European higher education area. Moreover, advances in computer calculations and its applications for structural analysis have brought a revolution in the professional area of structural engineering. Considering these circumstances, we have designed and implemented an educational program for teaching steel structures based on a Project based learning (PBL) method. In this paper we summarize the main features of the educational program, its implementation, results and evaluation; we analyze the performance of PBL in our context and compare some aspects of traditional teaching and our PBL; and finally we identify the most important characteristics required by teaching steel structures through the project based learning method.
Pelli Tower in Sevilla: a new concept in the building architecture
(Víctor Compán Cardiel [etc.], 2015) Hinojosa Sánchez-Barbudo, Ignacio; Garrido Conejero, José Raul; Medina Gil, Blas; Vicent Velasco, José Vicente
Pelli Tower is being built in the City of Sevilla. A new concept of building Architecture is born. Singularities are being described in the article: structural typology, materials, loads considered in the calculations (seism and wind tunnel Test), and construction methods used in the execution. A list of the main quantities used in the Pelli Tower is included to emphasize the importance of the execution.
Optimization of connections for spatial modular structures
(Víctor Compán Cardiel [etc.], 2015) Rodríguez-León, María Teresa; Sánchez Sánchez, Jesús; Vázquez Vicente, Enrique; Universidad de Sevilla. Departamento de Estructuras de Edificación e Ingeniería del Terreno
Every year Seville’s city Council orders the construction of a giant gateway for the celebration of the April Fair. These constructions, whose dimensions are approximately 50 meters length, 40 meters height and variable depth of 4 to 5 meters, are spatial modular structures composed of steel tubular elements connected by clamps and covered by wood boards. The consideration or not of the eccentricities introduced by the connection element as well as the determination of the stiffness to consider is one of the major problems when developing the analysis model. The construction company aims to achieve their optimization in order to reduce the final cost. This paper investigates about how different ways of modeling these connections affects the optimization of the final model. The extent to which the modification of the position of the eccentricities influences the optimization is also discussed, as this aspect is difficult to control on site.
Optimización de una cimentación pilotada y de la superestructura de un centro comercial mediante simulación de la interacción terreno-estructura en suelos licuefactables con un caso de sismo dimensionante : análisis comparativo de los resultados con y sin interacción terreno estructura
(Víctor Compán Cardiel [etc.], 2015) Carames, Carlos; Ibañez, Javier; Cantó, José Vicente
Soil-structure interaction techniques have been widely written about and largely used in the Energy domain, even if they are still not commonly used among Civil Engineers. Nevertheless, these techniques have been introduced in the latest versions of earthquake codes and their use can lead to large optimizations. The aim of this article is to show a practical methodology to take into account soil-structure interaction in seismic design applied to buildings through a real case where structural optimizations lead to savings valued in 17.5 M€. The structural study is done using a classical modal - spectral seismic analysis completed with the addition of dynamic impedances that reproduce soil structure interaction. This approach accurately incorporates the effects of the soil deformation by shifting the natural frequency of the structure and increasing the global damping of the system. The amount of energy dissipated in the soil is demonstrated in the analysis of the modal damping.
Optimal TMD-based control strategy for human-induced vibrations
(Víctor Compán Cardiel [etc.], 2015) Wang, Xidong; Díaz, Iván M.; Pereira, Emiliano; Xu, Qimen
Civil engineering structures such as office floors and singular footbridges may present vibration modes locally spatially distributed with closely spaced natural frequencies. A set of tuned mass dampers (TMDs) may control several vibration modes at the same time and make the control system more robust. However, under these circumstances, Den Hartog’s theory may not be applicable. In this paper, an optimum algorithm to design a set of TMDs is proposed to cancel effectively human-induced vibrations for floor structures. A comparative study is carried out in terms of the same performance indicator to find the optimum system, considering different configurations by Den Hartog’s classical approach and this optimal algorithm. This proposed algorithm will contribute to motivate future researches on passive vibration control (PVC) for floor vibrations with closely spaced natural frequencies.

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