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One of the most effective ways to encourage the use of new approaches like BIM consists on applying Project Based Learning (PBL). According to this methodology, teams might gain knowledge and skills by solving a realistic challenge, that is to say, they learn by doing. In this way, team members can experiment and investigate by themselves. BIM contests stands as one of the most encouraging PBL activities. This format has the additional advantage that all teamOne of the most effective ways to encourage the use of new approaches like BIM consists on applying Project Based Learning (PBL). According to this methodology, teams might gain knowledge and skills by solving a realistic challenge, that is to say, they learn by doing. In this way, team members can experiment and investigate by themselves. BIM contests stands as one of the most encouraging PBL activities. This format has the additional advantage that all teams work on the same problem, what eases the comparison of the results. In this sense, the analysis of the proposed Building Execution Plan (BEPs) provides useful insights about the know-how of the different designs. Despite the interest and usefullness of these results, no comparisons of similar BIM work flows have been carried out. To solve this gap, this paper analyzes, for the first time, the BEPs of the BIM projects presented in the different calls of the international contest BIM Valladolid. This analysis provides a useful insight about the most common software in each discipline. The evolution of the software of teams throughout time, as well as the information flows between the modeling and the structural analysis software of the proposals are also presenteds work on the same problem, what eases the comparison of the results. In this sense, the analysis of the proposed Building Execution Plan (BEPs) provides useful insights about the know-how of the different designs. Despite the interest and usefullness of these results, no comparisons of similar BIM work flows have been carried out. To solve this gap, this paper analyzes, for the first time, the BEPs of the BIM projects presented in the different calls of the international contest BIM Valladolid. This analysis provides a useful insight about the most common software in each discipline. The evolution of the software of teams throughout time, as well as the information flows between the modeling and the structural analysis software of the proposals are also presented

Today, low-cost sensors in various civil engineering sectors are gaining the attention of researchers due to their reduced production cost and their applicability to multiple nodes. Low-cost sensors also have the advantage of easily connecting to low-cost microcontrollers such as Arduino. A low-cost, reliable acquisition system based on Arduino technology can further reduce the price of data acquisition and monitoring, which can make long-term monitoring possible. This paper introduces a wireless Internet-based low-cost data acquisition system consisting of Raspberry Pi and several Arduinos as signal conditioners. This study investigates the beneficial impact of similar sensor combinations, aiming to improve the overall accuracy of several sensors with an unknown accuracy range. The paper then describes an experiment that gives valuable information about the standard deviation, distribution functions, and error level of various individual low-cost sensors under different environmental circumstances. Unfortunately, these data are usually missing and sometimes assumed in numerical studies targeting the development of structural system identification methods. A measuring device consisting of a total of 75 contactless ranging sensors connected to two microcontrollers (Arduinos) was designed to study the similar sensor combination theory and present the standard deviation and distribution functions. The 75 sensors include: 25 units of HC-SR04 (analog), 25 units of VL53L0X, and 25 units of VL53L1X (digital). The authors are indebted to the Spanish Ministry of Economy and Competitiveness for the funding provided through the research project BIA2017-86811-C2-1-R, directed by José Turmo, and BIA2017-86811-C2-2-R, directed by Jose Antonio Lozano-Galant. All these projects are funded with FEDER funds. Authors are also indebted to the Secretaria d’ Universitats i Recerca de la Generalitat de Catalunya, Catalunya, Spain for the funding provided through Agaur (2017 SGR 1482). It is also to be noted that funding for this research has been provided for Seyedmilad Komarizadehasl by the Spanish Agencia Estatal de Investigación del Ministerio de Ciencia Innovación y Universidades grant and the Fondo Social Europeo grant (PRE2018-083238).

The Building Information Modeling (BIM) methodology improves architectural and infrastructure projects by digitizing their processes throughout their life cycle stages, such as design, construction, management, monitoring, and operation. In recent years, the automation of these processes has been favored by the use of visual programming (VP) tools that have replaced conventional programming languages for visual schemes. The use of these tools in architectural projects is becoming increasing popular. However, this is not the case in infrastructure projects, for which the use of VP algorithms remains scarce. The aim of this work is to encourage both scholars and engineers to implement VP tools in infrastructure projects. For this purpose, this work reviews, for the first time in the literature, the state-of-the-art and future research trends of VP tools in infrastructure projects. This work was funded by the National Agency for Research and Development (ANID) for the Scholarship Program “DOCTORADO BECAS CHILE/2019”–Folio n°72200098 and by the Spanish Ministry of Economy and Competitiveness and the FEDER fund through the projects BIA2017-86811-C2-1-R directed by José Turmo and BIA2017-86811-C2-2-R. Authors are also indebted to the Secretaria d’ Universitats i Recerca of the Generalitat de Catalunya for the funding provided through Agaur (2017 SGR 1481).

Nowadays, engineers are widely using accelerometers to record the vibration of structures for structural verification purposes. The main obstacle for using these data acquisition systems is their high cost, which limits its use to unique structures with a relatively high structural health monitoring budget. In this paper, a Cost Hyper-Efficient Arduino Product (CHEAP) has been developed to accurately measure structural accelerations. CHEAP is a system that is composed of five low-cost accelerometers that are connected to an Arduino microcontroller as their data acquisition system. Test results show that CHEAP not only has a significantly lower price (14 times cheaper in the worst-case scenario) compared with other systems used for comparison but also shows better accuracy on low frequencies for low acceleration amplitudes. Moreover, the final output results of Fast Fourier Transformation (FFT) assessments showed a better observable resolution for CHEAP than the studied control systems. This research was funded by the Spanish Ministry of Economy and Competitiveness, grant number BIA2017-86811-C2-1-R; the Spanish Ministry of Economy and Competitiveness, grant number BIA2017-86811-C2-2-R; the Secretaria d’ Universitats i Recerca de la Generalitat de Catalunya, Catalunya, Spain, grant number 2017 SGR 1482; Spanish Agencia Estatal de Investigación del Ministerio de Ciencia Innovación y Universidades grant and the Fondo Social Europeo grant, grant number PRE2018-083238; Shanghai Qizhi Institute, grant number SYXF0120020109.

Infrastructures such as aerial tramways carry unique traffic operations and have specific maintenance requirements that demand constant attention. It is common that old structures lack any type of automatization or monitoring systems, relying only on human judgment. Owners are interested in implementing techniques that assist them in making maintenance decisions, but are reluctant to invest in expensive and complex technology. In this study, researchers discussed with the owners different options and proposed a sustainable and cost-efficient solution to monitor the Sandia Peak Tramway operations with just two strategically located acceleration sensors. To maximize the success options researchers worked with the owners and developed a sensor that satisfied their needs. A Low-cost Efficient Wireless Intelligent Sensor 4—Outdoors (LEWIS 4) was developed, tested and validated during the experiment. Two solar-powered units were installed by the tramway staff and recorded data for three days. When retrieved, researchers analyzed the data recorded and concluded that with only two sensors, the acceleration data collected were sufficient to determine the position and location of the tramway cars. It was also found that the sensor on the tower provides data about the cable–tower interaction and the forces caused by the friction on the system, this being a critical maintenance factor. This work summarizes a methodology for infrastructure owners consisting of guidelines to design a sustainable and affordable monitoring approach that is based on the design, development and installation of low-cost sensors.

Deflections are commonly measured in the static structural system identification of structures. Comparatively less attention has been paid to the possibility of measuring rotations for structural system identification purposes, despite the many advantages of using inclinometers, such as a high resolution and being reference free. Although some work using rotations can be found in the literature, this paper, for the very first time, proposes a statistical analysis that justifies the theoretical advantage of measuring rotations. The analytical expressions for the target parameters are obtained via static structural system identification using the constrained observability method first. Combined with the inverse distribution theory, the probability density function of the estimations of the target parameters can be obtained. Comparative studies on a simply supported bridge and a frame structure demonstrate the advantage of measuring rotations regarding the unbiasedness and the extent of variation in the estimations. To achieve robust parameter estimations, four strategies to use redundant rotations are proposed and compared. Numerical verifications on a bridge structure and a high-rise building have shown promising results. This work was partially funded by the Scientific Research Fund of the Institute of Engineering Mechanics, China Earthquake Administration (grant no. 2019 EEEVL0401), National Natural Science Foundation of China (grant nos. 51878484), Spanish Ministry of Economy and Competitiveness and the FEDER fund through the projects BIA2013-47290-R and BIA2017-86811-C2-1-R directed by José Turmo and BIA2017-86811-C2-2-R, and the Natural Science Foundation of Shenzhen (grant no. JCYJ20190806143618723). The authors are also indebted to the Secretaria d’Universitats i Recerca de la Generalitat de Catalunya for the funding provided through Agaur (2017 SGR 1481). Part of this work was carried out through a collaborative agreement between Tongji University (China) and the Technical University of Catalonia, UPC. This included an exchange of faculty financed by the Chinese government. The financial support from the Chinese High-End Foreign Experts program (GDW20143100115) is greatly appreciated. Funding for this research has been provided to Jun Lei by the Chinese Scholarship Council through its program No. 201506260116 and by the Spanish Ministry of Economy and Competitiveness through its program BES-2014-07022 for his PhD stays.

This article presents the application of the problem-based learning (PBL) methodology for introducing the civil engineering task of bridge design and construction to high school students wi...

La metodología Building Information Modelling (BIM) está revolucionando la manera en la que se desarrollan los proyectos de ingeniería civil. Una de las muchas ventajas de esta metodología es el desarrollo de modelos 3D, los cuales pueden ser conectados con herramientas de realidad aumentada. Entre las múltiples ventajas de la aplicación de esta tecnología en el campo de la ingeniería civil, resalta la accesibilidad de obtención de un gran nivel de detalle e información de un determinado elemento, facilitando la visualización y comprensión para todos los agentes. Hoy en día, esta tecnología está consolidada en sectores como el turismo o los video juegos, y cada vez está siendo más popular en estudios de arquitectura o inmobiliarias. Sin embargo, la realidad aumentada es una tecnología en desarrollo, y por ahora sus aplicaciones en la ingeniería civil son relativamente escasas. El objetivo del presente artículo es ilustrar el estado actual de la aplicación de BIM y de realidad aumentada en la ingeniería civil. Con tal objetivo, se analizarán los softwares más representativos de realidad aumentada y se analizará su aplicación en un puente elaborado con BIM. Tras este análisis, se obtendrán conclusiones sobre la interoperabilidad entre ambos. Por último, se expondrán las ventajas e inconvenientes encontrados para la aplicación de realidad aumentada en el campo de la ingeniería civil.

Nowadays,low-cost sensors and acquisition devices have been emerging as an obvioussolution to many innovative applications such as Structural Health Monitoring (SHM) systems. In this paper,issues regarding dynamic data acquisition,as well as their respective solutions,are presented. Moreover, a comprehensive description through-out an inexpensive sensor network system using open-source hardware for a real-time acceleration data acquisition has beenpresented. The platform consists of an accelerometer, an Arduino board,and a computeras a data recorder and presenter. Data is recorded through an efficient microcontroller code that can provide a considerable reading frequency (up to 300Hz). Using Python, instant acceleration recording for all the threeaxes has been done. It is shown how the performance of the proposed system is efficientfor the field of SHM systems. The authors are indebted to the Spanish Ministry of Economy and Competitiveness for the funding provided through the research project BIA2017-86811-C2-1-R directed by José Turmo and BIA2017-86811-C2-2-R, directed by Jose Antonio Lozano-Galant. All these projects are funded with FEDER funds. Authors are also indebted to the Secretaria d’ Universitats i Recerca de la Generalitat de Catalunya for the funding provided through Agaur (2017 SGR 1481). It is also to be noted that funding for this research has been provided for MR. SEYEDMILAD KOMARIZADEHASL by Agencia Estatal de Investigación del Ministerio de Ciencia Innovación y Universidades grant and the Fondo Social Europeo grant (PRE2018-083238).

The use of Building Information Modelling (BIM) is getting more and more popular since governments worldwide are increasing the demand of this methodology as a requirement in their projects. One of the most encouraging ways to promote the use of this methodology is based on the so-called BIM contests, where practitioners are challenged to build a virtual model of a structure collaboratively. These challenges are usually designed to take the participants out of their comfort zone and to encourage them to experiment in the use of the latest software and collaborative software connections. Unlike other activities encouraging BIM, these contests have the additional advantage of easing the comparison in terms of software, exchange file formats and information flows as all the proposals are framed into a common project with the same working time. Despite the interest of this kind of comparative analyses, no studies of the results of BIM contest proposals can be found in the literature. To fill this gap, this paper analyses the summary reports of the different proposals submitted in three editions (2014, 2015 and 2016) of the BIM Valladolid contest in Spain. The results of this study provide usefull insights into the use of software in a number of disciplines (Architecture, Structural Analysis, Energy Efficiency, Measurements and Budget, Facilities, Planning Execution and Coordination) and the most common file exchange formats. The evolution of teams in software use throughout the different contest editions as well as the information flow among the Architecture and the Structural Analysis disciplines are also analyzed.

Resumen En la mayoria de vigas mixtas, la conexion entre el hormigon y el acero es imperfecta y, por tanto, aparece un mayor o menor deslizamiento relativo entre ambos materiales. Este deslizamiento afecta tanto a las deformaciones como a los esfuerzos de la viga. Para simular este fenomeno, en este trabajo se propone un nuevo modelo de elementos finitos bidimensional basado en elementos tipo viga, facilitando asi la interpretacion y la aplicacion practica de los resultados. Para validar la precision del modelo, se comparan los resultados obtenidos mediante el modelo con los derivados de las ecuaciones analiticas propuestas en la literatura, en dos estructuras mixtas con diferentes estados de carga.

Despite its importance in some structures, shear deformation is systematically neglected by most static structural system identification methods. This paper analyzes for the first time in the literature the effect of this deformation in the static inverse analysis of thin web bridges. This study is focused on the observability techniques. The most recent formulation found in the literature is based onthe Euler-Bernoulli beam theory. This formulation is unable to identify correctly the characteristics of a structure (such as flexural stiffness) when shear deformation is not negligible. To solve this problem, the observability method is updated according to Timoshenko's beam theory. This formulation uses an algebraic method which combines a symbolical and a numerical application. Thus, the updated observability formulation is able to obtain not only the flexural stiffness but also the shear one. Besides this, a parametric equation of the estimates is obtained for the first time in the literature. Some examples of growing complexity are used to illustrate the validity of the the proposed formulation formulation.

In the field of bridge structural system identification (SSI), Bernoulli beam element models are often used to solve inverse problems. More rarely, Timoshenko beam element models can be calibrated. However, these models account for only the general shear effects, whereas other shear effects, such as shear lag, are not accounted for. However, as wide-flange box girder bridges become prevalent due to design demands, neglecting shear lag may introduce significant errors in predicting the mechanical parameters of the system and, hence, reduce the accuracy. In this paper, for the first time, the shear lag's effect on the vertical deflections is taken into account in an inverse problem. A parametric SSI, the observability method (OM), is updated to address the identification of thin-walled box girder bridges with wide flanges, including the shear lag effects. The structural analytical equations are used to connect the spatial shear effects with the beam-unidimensional-element model to be applied in the inverse analysis, which is referred to as the analytical observability method (AOM-SSI). This updated version of the OM is established and validated to identify the mechanical parameters of a structural test. The identified mechanical parameters show much better agreement with the expected results than those obtained with previous methods. This work was supported by BIA2017-86811-C2-1-R Spanish Ministry of Economy and Competitiveness, Spain. It was also supported by the Innovation Group Project, Natural Science Foundation of Hubei, China (Grant No. 2020CFA047) and the National Natural Science Foundation of China (Grant No.52178104).

Traditionally, Spanish schools of civil engineering provide their students a class on “Technical English” in order to develop their language skills. However, this class does not cover all the skills that the student would need in the labor market and mainly focuses in the reading and writing skills, and in a lower degree in the speaking and listening ones. This paper proposes a series of innovative and informal training activities, such as cine-forum on technical civil engineering topics and role playing on real professional situations, that allow Spanish civil engineering students to develop English skills, that can rarely be worked in the classroom (i. e. speaking, negotiating and conversing), which encourage debate, participation, and foster their self-confidence to speak about technical-English topics in public. Although the students’ level of English is much lower than expected, they all agree on the importance of technical English for their future career. The results also show the students’ lack in skills that are difficult to train in regular classes (speaking and talking). Consequently, this situation would require to provide complementary activities like the ones suggested in this project in order to develop these skills and increase the students’ demand for engineering classes taught in English. В последние годы традиционное преподавание с использованием обычной доски дополняется визуальными средствами, такими как слайд-проекторы и видео. Феноменальный рост Интернета привел к появлению новых учебных средств массовой информации, таких как онлайн-курсы общего пользования, которые делают доступными образовательные ресурсы для более широкого и удаленного контингента студентов. Легкий доступ к образованию может повысить мотивацию, что является полезным коммерческим инструментом для университетов. В отличие от других дисциплин, таких как экономика или психология, МООК редко используются для распространения курсов по дисциплинам направления «Строительство». Чтобы восполнить этот пробел и поощрить использование МООК среди строительных университетов, в настоящем документе представлен опыт создания такого курса для многодисциплинарного проектирования мостов, созданных Университетом Кастилии и Ла Манча. Этот курс основан на опыте, полученном на конкурсе по строительству мостов с заданиями для студентов‑магистрантов, организованных Университетом Кастилии и Ла Манча в 2015, 2016 и 2017 годах.

[EN] This paper describes a study of the Tempul Aqueduct, one of the first structures designed and built by Eduardo Torroja. At a time when computers did not exist, Torroja's courage and innovation were outstanding. He was in no way constrained by a lack of theoretical knowledge, inadequate materials and the contemporary doubts about cable-stayed structures. In fact, he was able to build one of the world's first prestressed concrete structures, and a precursor to modern cable-stayed and extradosed bridges. This paper briefly reviews the history of the Tempul Aqueduct, gives the results of the analysis of this structure by several Finite Element Models (FEMs), and compares the FEM results to those obtained by Torroja himself. The FEM results confirm the validity of Torroja's conceptual design. The paper also contains a detailed analysis of the influence of the structural system on the behavior of the bridge and the effect of removing the live loads with the aim of providing a better understanding of the context and behavior of the Tempul aqueduct., Funding for this research has been provided to Mr Lozano-Galant by the Spanish Ministry of Economy, Industry and Competitiveness (Research Project BIA2013-47290-R from FEDER funds). The authors are also grateful to Prof. S. Buonopane of Bucknell University and J.L. Temprado, of COMPOSAN, for their assistance and support. The authors also want to thank the CEHOPU-Archivo Torroja, for all the information and support provided.

[EN] Solving optimization problems using heuristic algorithms requires the selection of its parameters. Traditionally, these parameters are selected by a trial and error process that cannot guarantee the quality of the results obtained because not all the potential combinations of parameters are checked. To fill this gap, this paper proposes the application of Taguchi's orthogonal arrays to calibrate the parameters of a heuristic optimization algorithm (the descent local search algorithm). This process is based on the study of the combinations of discrete values of the heuristic tool parameters and it enables optimization of the heuristic tool performance with a reduced computational effort. To check its efficiency, this methodology is applied to a technical challenge never studied before: the optimization of the tensioning process of cable-stayed bridges. The statistical improvement of the heuristic tool performance is studied by the optimization of the tensioning process of a real cable-stayed bridge. Results show that the proposed calibration technique provided robust values of the objective function (with lower minimum and mean values, and lower standard deviation) with reduced computational cost., The authors are indebted to the Spanish Ministry of Economy and Competitiveness for the funding provided through the research projects BIA2013-47290-R and BIA2017-86811-C2-1-R founded with FEDER funds and directed by Professor Jose Turmo and through the research project BIA2017-86811-C2-2-R directed by Jose Antonio Lozano-Galant.

Structural Health Monitoring (SHM) is essential to assess the accuracy of durability predictions of structures. Using low-cost sensors on structural evaluation has gained significant attention compare to high-cost sensors. Although these may not be as accurate and sensitive as the expensive electronic devices, with efficient code and right use, there is a possibility of getting useful information from them. These sensors can vary based on their functionality and the measurements they provide. For example, one is highly sensitive to the light of its environment while the other kind would give different results in different temperatures. In this paper, three different displacement measuring sensors have been studied. An ultrasonic sensor (HC-SR04) and two different types of laser sensors (VL53L0X and VL53L1X) are investigated in the paper. An Arduino Mega has captured their measured data, and a raspberry pi has made the acquisition. Not only issues regarding coding and placing of these sensors have been presented ultimately, but precise solutions for the aforementioned problems as well as an efficient way of assembling all the sensors are also presented in this paper. The data generated from these electronic devices can be used for Structural Health Monitoring applications. The authors are indebted to the Spanish Ministry of Economy and Competitiveness for the funding provided through the research project BIA2017-86811-C2-1-R directed by José Turmo and BIA2017-86811-C2-2-R, directed by Jose Antonio Lozano-Galant. All these projects are funded with FEDER funds. Authors are also indebted to the Secretaria d’ Universitats i Recerca de la Generalitat de Catalunya for the funding provided through Agaur (2017 SGR 1482). It is also to be noted that funding for this research has been provided for MR. SEYEDMILAD KOMARIZADEHASL by Agencia Estatal de Investigación del Ministerio de Ciencia Innovación y Universidades grant and the Fondo Social Europeo grant (PRE2018-083238).

Temperature and humidity measurements provide useful information on multiple areas of civil engineering application such as Structural Health Monitoring (SHM), Structural System Identification (SSI) and structures rehabilitation. Majority of the existing commercial systems are so costly and also these measurement paradigms need many reference spots for a full-scale structure. The aforesaid paradigms are based on collecting data through smart devices, transferring information to each other and in the final stage processing the obtained information collaboratively through cloud computing or the others technologies. Taking into account the above information and obstacles, utilizing the Open Source Platforms (OSP) microcontrollers like Arduino as well as low cost sensors are attracting more and more attention. This paper gives a comprehensive information about the most determinant aspects of the aforementioned kits in terms of their pros and cons, installation procedure, communication protocol, number of the required connections and specific characteristics of the data acquisition system, Las mediciones de temperatura y humedad proporcionan información útil en múltiples áreas de aplicación de la ingeniería civil, como la monitorización de la salud estructural (SHM), la identificación de sistemas estructurales (SSI) y la rehabilitación de estructuras. La mayoría de los sistemas comerciales existentes son muy costosos y además estos paradigmas de medición necesitan muchos puntos de referencia para una estructura a escala real. Dichos paradigmas se basan en la recogida de datos a través de dispositivos inteligentes, la transferencia de información entre ellos y, en la etapa final, el procesamiento de la información obtenida de forma colaborativa a través de la computación en la nube u otras tecnologías. Teniendo en cuenta la información y los obstáculos anteriores, la utilización de microcontroladores de plataformas de código abierto (OSP) como Arduino, así como de sensores de bajo coste, está atrayendo cada vez más atención. Este artículo ofrece una información exhaustiva sobre los aspectos más determinantes de los kits mencionados en términos de sus pros y sus contras, el procedimiento de instalación, el protocolo de comunicación, el número de conexiones necesarias y las características específicas del sistema de adquisición de datos.

In the last years, more and more studies highlight the advantages of complementing traditional master classes with additional activities that improve students´ learning experience. This combination of teaching techniques is specially advised in the field of structural engineering, where intuition of the structural response it is of vital importance to understand the studied concepts. This paper deals with the introduction of a new (and more encouraging) educational tool to introduce intuitively students in the dynamic response of structures excited with an educational shaking table. Most of the educational structural health monitoring systems use sensors to determine the dynamic response of the structure. The proposed tool is based on a radically different approach, as it is based on low-cost image-recognition techniques. In fact, it only requires the use an amateur camera, a black background and a computer. In this study, the effects of both the camera location and the image quality are also evaluated. Finally, to validate the applicability of the proposed methodology, the dynamic response of small-scale buildings with different typologies is analyzed. In addition, a series of surveys were conducted in order to evaluate the activity based on student´s satisfaction and the actual acquisition and strengthening of knowledge.

Identification of the mode shapes through monitoring is one of the key problems in damage diagnosis based on modal parameters especially for damaged structures. In order to obtain mode shapes of damaged structures easily and accurately, the mass-stiffness combined perturbation (MSCP) method is proposed in this paper. To do so, the relationship between the stiffness perturbation mode shapes of damaged and intact structures is firstly derived and established. Then, the principle of similar frequency is applied to optimize the objective function of the most suitable mass perturbation model. Both numerical analyses and experimental tests on simple and complex structures demonstrate that the proposed MSCP method achieves higher precision than traditional mode shape identification methods. The additional advantages of the MSCP method include (i) lower requirement on the frequency analysis of only damaged structures and (ii) higher effectiveness for minor damage scenarios. In fact, the lower the damage, the higher the precision achieved by the MSCP method. As illustrated in the paper, the proposed technique has excellent applications in mode shapes identification and structural health monitoring.

Structural system identification (SSI) is a powerful tool for the assessment of the current condition of structures in operation. The basic assumption is that the deterioration of structures is reflected in the change of structural parameters. In SSI, the observability of these parameters depends on the location and the number of sensors. If the available sensors are less than the required ones, some parameters might not be observed. Furthermore, the incapability of identifying all parameters might occur when the sensors are sufficient but placed improperly. An investigation was carried out using SSI by observability method when then number of measurements is the same as the number of sensors. It is seen that a large proportion of the studied measurement sets cannot ensure the observability of all parameters. To improve the observability of structural parameters, a two-stage static SSI method is presented to fully exploit the information in the measurements. In the first stage, the SSI problem is treated in a linear manner and thereby the computation is greatly reduced. In the following stage, the nonlinear relations among the variables in the formulated system are recovered and thus the capability of the method to observe those structural parameters is enhanced.

In a staggered erected cable-stayed bridge made of concrete, time-dependent phenomena (suchas creep or shrinkage) effects might play an important role in both its geometry and its stress state. In fact, because of these phenomena, stays will indeed lose force and higher bending moments will appear in the structure. To compensate these effects, one or two re-stressing operations are traditionally planned during the life time of long span cable- stayed bridges made of concrete. These re-stressing operations might be technologically challenging and always imply additional costs. To guarantee that allowable stresses and deflections are not exceeded during erection, a number of simulation methods are presented in the literature. Some of these methods, concretely those based on a backward simulation approach, fail addressing the effects of the timedependent phenomena. To simulate these effects, methods based on the forward simulation approach are traditionally followed. Nevertheless, the main trade-off of these algorithms is that their computation is based on complex iterative processes that make simulation more time consuming. Furthermore, these methods are not able to avoid the need of additional re-stressing operations in service to prevent the effects of the timedependent phenomena. To fill all these gaps, a new simulation algorithm, the Forward-Direct Algorithm (FDA), is formally presented in this paper to simulate the construction process of cable-stayed bridges including the time-dependent phenomena effects. This algorithm takes advantage of the unstressed length of the stays concept to carry out a computationally efficient simulation based on an innovative direct simulation approach. The major advantage of this algorithm is the fact that the prestressing operations during construction can be defined to avoid the need of additional re-tensioning operations in service. To illustrate the creep and shrinkage effects, the proposed algorithm is applied to a real cable-stayed bridge. This tool also can be used by the designer or the contractor for construction control of the strand by strand tensioning technique.

Traditionally, Spanish schools of civil engineering provide their students a class on “Technical English” in order to develop their language skills. However, this class does not cover all the skills that the student would need in the labor market and mainly focuses in the reading and writing skills, and in a lower degree in the speaking and listening ones. This paper proposes a series of innovative and informal training activities, such as cine-forum on technical civil engineering topics and role playing on real professional situations, that allow Spanish civil engineering students to develop English skills, that can rarely be worked in the classroom (i. e. speaking, negotiating and conversing), which encourage debate, participation, and foster their self-confidence to speak about technical-English topics in public. Although the students’ level of English is much lower than expected, they all agree on the importance of technical English for their future career. The results also show the students’ lack in skills that are difficult to train in regular classes (speaking and talking). Consequently, this situation would require to provide complementary activities like the ones suggested in this project in order to develop these skills and increase the students’ demand for engineering classes taught in English. Традиционно для студентов испанских строительных университетов проводятся курсы технического английского языка для повышения их уровня владения языком. Однако эти курсы ориентированы на чтение и письмо, в меньшей степени — на навыки разговорного языка и не охватывают всех компетенций, требующихся на рынке труда. В этой статье предлагается ряд новых и неформальных учебных методов (использование кинокамер при изучении вопросов гражданского строительства и ролевой игры в реальных профессиональных ситуациях), которые позволяют испанским студентам-строителям развивать навыки английского языка, которые трудно получить в обычном классе, что развивает уверенность, позволяет студентам овладевать навыками ведения переговоров, бесед, участвовать в дискуссиях. Хотя уровень владения английским языком испанских студентов намного ниже, чем ожидалось, все они согласны с важностью овладения техническим английским для дальнейшей карьеры. Результаты опросов также показывают отсутствие у студентов навыков, которые трудно тренировать в обычных классах (речь и разговоры). Таким образом, для развития навыков владения английским языком для студентов‑строителей требуются дополнительные методики, которые предлагаются в этом проекте.

This paper presents a finite element model for the analysis of composite beams with partial interaction. In this model, the elements of the composite beams are modeled by six different types of frame elements. Compared with other methods presented in the literature, the main advantages of the proposed method are as follows: (1) intuitiveness, as the different elements of the model present a close and easy to understand relation with the structural behavior of the composite beam; (2) applicability as the method directly provides useful information for the design work; (3) versatility and generalization in dealing with any combination of loading and boundary conditions (Furthermore, the proposed model enables the analysis of statically indeterminate structures, tapered beams as well as structures with non-uniform shear connector distributions.); (4) easy elaboration of models; and (5) possible widespread use of the model, as the proposed method can be implemented in any structural software. To validate the accuracy and the efficiency of the proposed model, a set of FEMs are verified against those results obtained by analytical equations available in the literature for different boundary and loading conditions. Furthermore, a set of parametric studies are performed to investigate the effects of the size of the FEMs along with the influence of the connection stiffness on the behavior of composite beams with different I beams.

This is the peer reviewed version of the following article: [Lei J, Nogal M, Lozano-Galant JA, Xu D, Turmo J. Constrained observability method in static structural system identification. Struct Control Health Monit. 2018;25:e2040. https://doi.org/10.1002/stc.2040], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/stc.2040/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. Identifiability of parameters in structural system identification (SSI) is of primary importance in any SSI method. It depends on the number and the location of the measurements, which is linked with sensor configuration. In this paper, under the framework of SSI by observability method (OM), the number of necessary measurements to identify all parameters of structural system was clarified first. Then, an example was solved step by step to show the lacking constraints among unknowns in SSI by OM. In a frame example, it was found that no measurement set having as many measurements as the number of unknowns was able to identify all parameters. To further understand this phenomenon, the observability of a simply supported beam was analyzed in an exhaustive way using 252 possible measurement sets. Three quarters of these sets were not able to identify all the parameters. In order to solve this issue, for the very first time, SSI by constrained observability method (COM), which appends the nonlinear constraints to SSI by OM, was proposed. With SSI by COM applied, the observability of the structural parameters with respect to the 252 sets was greatly improved. Finally, the efficacy of SSI by COM was verified by a 13-story frame building.

Construction of cable stayed bridges is very challenging. These structures are extremely redundant and the effect of tensioning one cable has the effect of changing the stresses of the already installed cables. In order to achieve a targeted service state at the end of the construction process careful calculations has to be done by the contractor in order to ensure it. However, deviations arise between the modelling of the tensioning process and the actual results obtained on site. In order to adjust the final stresses in the cables, a final restress of the stays is unusually required. This re-stressing operation is usually done for the whole cable, as the strand by strand stressing technique used for the first stressing operations, cannot be used anymore. This last operation is costly, time consuming and has less accuracy, compared with the strand by strand tensioning techniques. The paper will present a method to control the tensioning process on site and to modify it according to the stresses measured in the cables at each stressing stage. In this way, the chances of requiring a restressing operation are diminished.

The usual moderate dimensions of footbridges allow design architects (and sometimes engineers) to provide such structures with capricious forms. Under such circumstances, the analysis of the service state is usually very thorough, devoting to the study of the construction stages much less attention. However, it is very well known that the construction procedure can determine the service stage. Moreover, dimensions of footbridges also allow a wide range of construction procedures. For example, when cables are used to help to support the deck, as in cable stayed bridges, those are, namely, cantilever method, temporary support method, movement of the bridge to its final position as well as bridge launching. When the cables are used in tied arch bridges most of the previously mentioned methods might be used, especially temporary support method, movement of the bridge to its final position as well as bridge launching techniques. Having this in mind, it is crucial for the designer and for the contractor to have practical tools for construction control of the tensioning process of the stays, as this will condition the service stresses of the bridges. This is challenging, as the prestressing of one stay affects the stresses of the already installed stays. This paper will present a procedure to calculate the stress to be given to the first strand of a stay when the strand by strand tensioning technique is used. Also, a procedure to modify the tensioning process of a cable supported bridges to minimize deviation between design and actual stay stresses in service will be presented.

Traditionally, Spanish schools of civil engineering provide their students a class on “Technical English” in order to develop their language skills. However, this class does not cover all the skills that the student would need in the labor market and mainly focuses in the reading and writing skills, and in a lower degree in the speaking and listening ones. This paper proposes a series of innovative and informal training activities (cine-forum on technical civil engineering topics and role playing on real professional situations) that allow Spanish civil engineering students to develop English skills that can rarely be worked in the classroom (i.e. speaking, negotiating and conversing), encouraging debate, participation, and fostering their self-confidence to speak about technical-English topics in public. Although the students’ level of English is much lower than expected, they all agree on the importance of technical English for their future career. The results also show the students’ lack in skills that are difficult to train in regular classes (speaking and talking). Consequently, this situation would require to provide complementary activities like the ones suggested in this project in order to develop these skills and increase the students’ demand for engineering classes taught in English.

Externally anchored prestressed cables can be employed to enhance the stability of steel truss compression elements significantly. To demonstrate this concept, a system comprising a tubular strut subjected to an external compressive load and a prestressed cable anchored independently of the strut is studied. Energy methods are utilized to define the elastic stability of the perfect and imperfect systems, after which the first yield and rigid–plastic responses are explored. The influence of the key controlling parameters, including the length of the strut, the axial stiffness of the cable and the initial prestressing force, on the elastic stability, the inelastic response and the ultimate strength of the system is demonstrated using analytical and finite element (FE) models. To illustrate the application of the studied structural concept, FE modelling is employed to simulate the structural response of a prestressed hangar roof truss. A nearly two-fold enhancement in the load-carrying capacity of the truss structure is shown to be achieved owing to the addition of the prestressed cable.

During the first step in the development of any structural system identification method, the method should be validated by noise-free measurements in the first place. Nevertheless, this assumption is far from reality as the measurements in these tests are always subjected to the errors of measurement devices. To fill this gap, this paper analyzes the effects of measurement errors in a parametric structural system identification method: the observability method. To illustrate the symbolic approach of this method a simply supported beam is first analyzed in detail. This simulation provides the parametric equations of the estimates. Then, the effects of errors in a particular measurement, errors in all measurements, load locations are studied in this structure. Two additional examples of increasing complexity are also analyzed to show the effect of modelling errors on the estimates. A fluctuation of the observed parameters around the real values is proved a characteristic of this method. The results of these structures illustrate how important the effects of modelling errors are especially in areas with low curvatures.

The rapid bloom of cable-stayed bridges has been propitiated by the development of erection techniques and improvements of construction materials. Nevertheless, the economic boom of the last decade has deflected attention from economic cost to iconic aesthetical appearance increasing significantly designer’s freedom. This structural freedom has enabled the proliferation of a number of non-symmetric cable-stayed bridges. Despite of the number of built examples, the analysis of non-symmetrical cable-stayed bridges has not received considerable attention from the researchers. In fact, the effects of the main design parameters in the structural behavior of these bridges are not addressed in detail in the literature. To fill this gap, this paper studies the structural response of a number of non-symmetrical cable-stayed bridges. With this aim, a parametric analysis is performed to evaluate the effect of each of the main design parameters (the ratio between the main and the back span length, the pylon, the deck and backstay stiffnesses, the pylon inclination, and the stay configuration) of this kind of bridges. Furthermore, the role of the geometrical nonlinearity and the steel consumption in stays are evaluated.

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Structure and Infrastructure Engineering on 2016, available online at: http://www.tandfonline.com/10.1080/15732479.2015.1101143 This article proposes the application of the observability techniques to deal with damage detection in bridges from their structural response under static loading tests. Unlike previous works based on a symbolic approach to this technique, this article presents its first numerical application. With this aim, a novel algorithm is presented, which reduces the unavoidable numerical errors produced by the lack of precision of computers. To achieve an adequate accuracy in estimations, this numerical algorithm is complemented with another method to define the proper geometry of the corresponding finite element model. The comparison of the observability technique with other existing methods presented in the literature shows that the number of required measurements is significantly lower. Furthermore, contrary to other analysed methods, no information from the undamaged structure is required. The accuracy in estimations provided by the proposed method is very high as the differences with actual values are lower than 1%.