- I am a Civil Engineering Professor at Universidad Politécnica de Madrid (Spain), where I teach Hydraulics. I am also an expertise in structural dynamics and harbour constructionedit
ResumenEl avance continuo de la tecnología en los teléfonos móviles ha facilitado el desarrollo de aplicaciones más complejas y especializadas. En la actualidad se pueden encontrar aplicaciones móviles sencillas para el cálculo de... more
ResumenEl avance continuo de la tecnología en los teléfonos móviles ha facilitado el desarrollo de aplicaciones más complejas y especializadas. En la actualidad se pueden encontrar aplicaciones móviles sencillas para el cálculo de estructuras. En este trabajo, se da un paso más con una nueva aplicación para análisis dinámico. Más concretamente, se ha desarrollado una aplicación móvil que permite valorar el estado de servicio de vibraciones en estructuras y que puede ser utilizada tanto por profesionales como para la impartición de cursos de master en análisis dinámico. En este artículo se muestran los resultados obtenidos con la aplicación desarrollada, DynApp, en diversas pasarelas peatonales de la ciudad de Madrid. Estas campañas experimentales se han realizado por los alumnos de dos cursos de master de la Escuela de Caminos de la UPM: Análisis Experimental de Estructuras y Análisis Dinámico y Sísmico de Estructuras.The continuous advance of smartphone technologies has promoted th...
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Research Interests: Physics and HIDROLOGÍA
Flash floods are of major relevance in natural disaster management in the Mediterranean region. In many cases, the damaging effects of flash floods can be mitigated by adequate management of flood control reservoirs. This requires the... more
Flash floods are of major relevance in natural disaster management in the Mediterranean region. In many cases, the damaging effects of flash floods can be mitigated by adequate management of flood control reservoirs. This requires the development of suitable models for optimal operation of reservoirs. A probabilistic methodology for calibrating the parameters of a reservoir flood control model (RFCM) that takes into account the stochastic variability of flood events is presented. This study addresses the crucial problem of operating reservoirs during flood events, considering downstream river damages and dam failure risk as conflicting operation criteria. These two criteria are aggregated into a single objective of total expected damages from both the maximum released flows and stored volumes (overall risk index). For each selected parameter set the RFCM is run under a wide range of hydrologic loads (determined through Monte Carlo simulation). The optimal parameter set is obtained t...
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Research Interests: Computer Science, Real Time Computing, Wireless Systems, Structural Health Monitoring, Time Synchronization, and 12 moreTelecomunicaciones, Wireless Network, Electrónica, Wireless Sensor, Embedded Computing, Front end, Laboratory Tests, Wireless Sensor Network, Wireless Communication, Electrical And Electronic Engineering, Operation and Maintenance, and Measurement System
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Within the department of Civil Engineering: Hidrolic and Energetic at the UPM a new assessment system has been developed that counts on practical lab exercises to be solved through a web tool. Students registered in this subject are able... more
Within the department of Civil Engineering: Hidrolic and Energetic at the UPM a new assessment system has been developed that counts on practical lab exercises to be solved through a web tool. Students registered in this subject are able to access on a personal basis and find exercises to solve according to data obtained in the lab. These exercises allow numerical answers to the results within a range of error facilitated by each one of them. The system allows students to know their grades immediately after doing the exercise and limits execution time to each of the groups of practice in an independent way; imposing one or several input random data within a determined range of variation. Each practice has an explanatory pdf associated to it and it can be attached to any other graphic document, html, or flash, as desired. The system is developed using OpenSource tools.
Some advances in extensive bridge monitoring using low cost dynamic characterization Structural Health Monitoring (SHM) systems have excellent potential to improve the regular operation and maintenance of the structures. Wireless Sensor... more
Some advances in extensive bridge monitoring using low cost dynamic characterization Structural Health Monitoring (SHM) systems have excellent potential to improve the regular operation and maintenance of the structures. Wireless Sensor Networks (WSN) have been used to avoid high cost of traditional generic wired systems. The most important limitations in SHM wireless systems are time synchronization accuracy, scalability and reliability. In this article, a complete wireless system for structural identification under environmental load is presented. Our contribution ranges from the hardware to the graphical front-end. The system is paying attention in avoiding the main limitations of WSN for SHM specially focused in reliability, scalability, and synchronization. In order to validate the system we have carry out different tests: check synchronization at the lab, compare our operational modal analysis over a real bridge with a numeric analysis and analyze the results of a comparison b...
Changes into the dynamic behavior of structures can be used within a vibration monitoring system to assess the structural integrity. A number of examples of different structures equipped with vibration monitoring systems can be found.... more
Changes into the dynamic behavior of structures can be used within a vibration monitoring system to assess the structural integrity. A number of examples of different structures equipped with vibration monitoring systems can be found. However, it is quite rare to find vibration monitoring system in buildings. Thus, this paper aims to demonstrate that the wireless monitoring system developed by the Research Group allows to identify successfully the modal parameters of in-service buildings and afterwards, quantify the uncertainties associated to the identification process. The uncertainty quantification is carried out using three different time-domain identification methods of operational modal analysis considering different time records for the analysis. Moreover, the influence of environmental factors on the modal estimates is preliminary studied.
Vibration-based monitoring was performed on a short-span skewed highway bridge on the basis of wireless measurements. By means of operational modal analysis, highly accurate modal results (frequencies and mode shapes) were extracted by... more
Vibration-based monitoring was performed on a short-span skewed highway bridge on the basis of wireless measurements. By means of operational modal analysis, highly accurate modal results (frequencies and mode shapes) were extracted by using a self-developed wireless acquisition system, for which the performance was verified in the field. In order to reproduce the experimental modal characteristics, a refined finite element model was manually tuned to reduce the idealization errors and then updated with the sensitivity method to reduce the parametric errors. It was found that to build a reliable Finite element (FE) model for application in structural health monitoring, the effects of superelevation and boundary conditions of a skewed bridge should be taken into account carefully.
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This paper presents a real-time flood control model for dams with gate-controlled spillways that brings together the advantages of an optimization model based on mixed integer linear programming (MILP) and a case-based learning scheme... more
This paper presents a real-time flood control model for dams with gate-controlled spillways that brings together the advantages of an optimization model based on mixed integer linear programming (MILP) and a case-based learning scheme using Bayesian Networks (BNets). A BNet model was designed to reproduce the causal relationship between inflows, outflows and reservoir storage. The model was trained with synthetic events generated with the use of the MILP model. The BNet model produces a probabilistic description of recommended dam outflows over a time horizon of 1 to 5 h for the Talave reservoir in Spain. The results of implementing the BNet recommendation were compared against the results obtained while applying two conventional models: the MILP model, which assumes full knowledge of the inflow hydrograph, and the Volumetric Evaluation Method (VEM), a method widely used in Spain that works in real-time, but without any knowledge of future inflows. In order to compare the results of...
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Friction pendulum systems (FPSs) are a common solution for isolating civil engineering structures under ground movements. The result is a base-isolated structure in which the base exhibits low shear stiffness in such a way that the input... more
Friction pendulum systems (FPSs) are a common solution for isolating civil engineering structures under ground movements. The result is a base-isolated structure in which the base exhibits low shear stiffness in such a way that the input energy of the earthquake is concentrated and dissipated into it, leaving the superstructure free of damage. As a consequence, large displacements of the FPS may be demanded depending on the earthquake intensity and the fundamental period of the FPS. To accommodate these displacements, large-size isolators with high friction coefficients are usually required. However, the FPS will then exhibit poor re-centering capacity and the risk of future shocks will increase due to previous residual displacements, especially for low-intensity earthquakes. An alternative solution is to include a semi-active damper to the FPS, keeping the friction coefficient low and achieving both, limited base displacement under high-intensity earthquakes and good re-centering c...
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The computational tool InSTHAn (indicators of short-term hydrological alteration) was developed to summarize data on subdaily stream flows or water levels into manageable, comprehensive and ecologically meaningful metrics, and to qualify... more
The computational tool InSTHAn (indicators of short-term hydrological alteration) was developed to summarize data on subdaily stream flows or water levels into manageable, comprehensive and ecologically meaningful metrics, and to qualify and quantify their deviation from unaltered states. The pronunciation of the acronym refers to the recording interval of input data (i.e., instant). We compared InSTHAn with the tool COSH-Tool in a characterization of the subdaily flow variability of the Colorado River downstream from the Glen Canyon dam, and in an evaluation of the effects of the dam on this variability. Both tools captured the hydropeaking caused by a dam operation, but only InSTHAn quantified the alteration of key flow attributes, highlighting significant increases in the range of within-day flow variations and in their rates of change. This information is vital to evaluate the potential ecological consequences of the hydrological alteration, and whether they may be irreversible,...
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Dynamic and experimental analysis of structures are two of the most abstract and complex disciplines in structural engineering, because of its awkward mathematical and physical background and due to the multidisciplinary knowledge needed... more
Dynamic and experimental analysis of structures are two of the most abstract and complex disciplines in structural engineering, because of its awkward mathematical and physical background and due to the multidisciplinary knowledge needed to go over the whole analysis (from the acquisition of measures up to the final interpretation of results). In particular, Fourier analysis (frequency domain analysis) in discrete time, which is routinely used in the dynamic analysis, is not usually well-understood and even is not well computed in discrete time. Frequently, students lose motivation trying to decrypt difficult mathematical developments, which do not let them to interpret properly complex concepts which are extremely important for current analysis in discrete time such as: Fourier transforms, aliasing, leakage, filtering, windowing, etc. For this reason, the authors has implemented a new teaching tools based on the numerical experiments and interactive learning that transform the lear...
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The extraction of modal parameters, eigen frequencies and associated eigen vectors, from acceleration records, is a complex process that requires vast engineering knowledge. This process depends on the raw data properties; signal noise... more
The extraction of modal parameters, eigen frequencies and associated eigen vectors, from acceleration records, is a complex process that requires vast engineering knowledge. This process depends on the raw data properties; signal noise ratio and setting recording parameters. Moreover, in the case of Operational Modal Analysis (OMA), the modal estimates are highly dependent on the technique and software employed parameters to select estimates from the stabilization diagram (i.e: modal order, maximum allowable damping, frequency tolerance, etc). The variation in the obtained modal parameters due to this numerical process can be as large as the influence on the exogenous factors. The influence of these factors on modal estimates have to be removed from the analysis if a modal estimate is to be used as a damage detection parameter. In this article, several automated OMA software programs are compared using the same input records. For each one, different input parameters are used in orde...
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Research Interests: Engineering, Civil Engineering, Modeling, Numerical Analysis, Pipeline, and 13 moreSensitivity Analysis, Structural Analysis, Nonlinear Analysis, Conceptual Framework, Displacement, Polyethylene, Computer Program, Marine Environment, Construction Process, A nonlinear analysis of laying a floating pipeline on the seabed, Stiffness Matrix, Bending Moment, and Nonlinear Dynamic Analysis
Shake tables are one of the most widespread means to perform vibration testing due to their ability to capture structural dynamic behavior. The shake table acceleration control problem represents a challenging task due to the inherent... more
Shake tables are one of the most widespread means to perform vibration testing due to their ability to capture structural dynamic behavior. The shake table acceleration control problem represents a challenging task due to the inherent non-linearities associated to hydraulic servoactuators, their low hydraulic resonance frequencies and the high frequency content of the target signals, among other factors. In this work, a new shake table control method is presented. The procedure relies on identifying the Frequency Response Function between the time derivative of pressure force exerted on the actuator’s piston rod and the resultant acceleration at the control point. Then, the Impedance Function is calculated, and the required pressure force time variation is estimated by multiplying the impedance by the target acceleration profile in frequency domain. The pressure force time derivative profile can be directly imposed on an actuator’s piston by means of a feedback linearization scheme,...