Proceedings of the Belgian-Dutch IABSE Young Engineers Colloquium 2019:YEC2019

The proceedings contain 35 papers. The topics discussed include: fatigue monitoring of railway bridges by means of virtual sensing; steel-supported glazed atrium roof between two adjacent existing buildings; the Boekelose bridge: an innovative structure; case study of rail-bridge interaction of a large span railway viaduct in riga; probabilistic approach to evaluate fatigue safety status in steel railway bridges; buckling design approach for unstiffened curved plates in uniform shear; finite element modeling of residual welding stresses in an orthotropic steel bridge component; uniformly loaded tensegrity bridge design via morphological indicators method; tensile and shear resistance of bolted connectors in steel-FRP hybrid beams; and parametric analysis of rib distortion induced stress concentration at rib-to-crossbeam joint.</p

Fabricate 2020

Fabricate 2020 is the fourth title in the FABRICATE series on the theme of digital fabrication and published in conjunction with a triennial conference (London, April 2020). The book features cutting-edge built projects and work-in-progress from both academia and practice. It brings together pioneers in design and making from across the fields of architecture, construction, engineering, manufacturing, materials technology and computation. Fabricate 2020 includes 32 illustrated articles punctuated by four conversations between world-leading experts from design to engineering, discussing themes such as drawing-to-production, behavioural composites, robotic assembly, and digital craft

A holistic methodology for the non-destructive experimental characterization and reliability-based structural assessment of historical steel bridges

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGNowadays, several historical steel structures present damage and an advanced deterioration state induced by human or natural actions, causing fluctuations in geometrical, physical, and mechanical properties that dramatically affect their mechanical behavior. Due to the economic, cultural, and heritage value, these constructions must be comprehensively assessed to verify their current condition state. This work presents a holistic methodology aimed at the non-destructive experimental characterization and reliability-based structural assessment of historical steel bridges. It comprehends from the experimental data acquisition to the finite element model updating and the probabilistic-based structural assessment to obtain the reliability indexes of serviceability and ultimate limit states. Several sources of information are considered in the evaluation process, thus, results are more realistic and accurate and can be used for optimal decision-making related to maintenance and retrofitting actions. The feasibility of the methodology has been tested on O Barqueiro Bridge, an aging riveted bridge located in Galicia, Spain. The study first involved a comprehensive experimental campaign to characterize the bridge effectively at multiple levels: geometry, material, and structural system by the synergetic combination of different tools and methods: in-depth visual inspection, terrestrial laser scanner survey, ultrasonic testing, and ambient vibration test. Subsequently, a detailed FE model was developed and calibrated with an average relative error in frequencies of 2.04% and an average MAC value of 0.94. Finally, the reliability-based structural assessment was performed, yielding reliability indexes of 1.80 and 1.99 for the serviceability and ultimate limit states, respectively. Thus, the bridge could not withstand traffic loads with satisfactory structural performance in its current condition.Ministerio de Ciencia, Innovación y Universidades | Ref. RTI2018-095893-B-C21European Regional Development Fund | Ref. EAPA_826/201

An inverse predictive model for the design of functional textiles

PhD ThesisCoated woven fabrics are used for large scale structures including airports and sports stadia. Manufacturers produce a range of fabrics from which a single fabric is selected by the structural engineer based on design criteria such as stiffness, weight, strength and formability. Designs must therefore utilise a fabric with properties which may not be optimal for that particular application. This thesis develops and tests a model that allows a bespoke coated woven fabric to be designed with specified mechanical properties such as tensile stiffness, Poison’s ratio and shear stiffness. A method is developed to ‘invert’ an existing predictive mechanistic ‘unit cell’ model using the derivatives of the equations defining the unit cell. The existing model is altered to enable the prediction of shear characteristics in addition to tensile properties by the inclusion of the coating using a finite element representation. The ‘inverse’ model is shown to accurately design a fabric for specific and attainable targets of Young’s modulus, Poisson’s ratio, and shear stiffness which have been derived using the predictive model for various fabric stress states. The effect of variability in fabric parameters on the tensile response of a fabric is considered using both Monte Carlo and FORM analysis. The sensitivity of the fabric response to biaxial loading is calculated using the direction cosines defined in the FORM methodology. The calculation of fabric sensitivity also enables a detailed investigation of the sensitivity of fabric stress-strain behaviour to variation in individual fabric parameters. A method is developed to design fabrics with mechanical properties which are robust to changes in manufacturing parameters by altering the geometry of the fabric. The model is validated by comparing the inverse model output to unit cell model input and also to biaxial test results. The inverse model shows excellent fidelity with results calculated using the unit cell model, but fails to adequately reproduce the actual fabric geometry when target stiffness values are based on biaxial test data. A method for the removal of yarns from fabrics and tensile testing of coated fabric yarn specimens is also developed. iii It is common practice to use a plane stress formulation to approximate the stress-strain response of a coated woven fabric. Comparison of the model output with biaxial test results necessitated the creation of a method for the calculation of fabric tensile stiffness at multiple stress states instead of a single set of elastic constants. This approach takes into account the complex nonlinear behaviour of architectural fabrics by considering the variation in stress-strain behaviour at different biaxial stress states. The final inverse model provides a novel tool for the design of coated woven fabric with prescribed mechanical responses at multiple stress states that is robust to variations in its constituent parameters, with scope for future application in textile architecture, medical textiles and industrial textiles

Measurements, Models, Systems and Design

531 s.

NASA space station automation: AI-based technology review

Research and Development projects in automation for the Space Station are discussed. Artificial Intelligence (AI) based automation technologies are planned to enhance crew safety through reduced need for EVA, increase crew productivity through the reduction of routine operations, increase space station autonomy, and augment space station capability through the use of teleoperation and robotics. AI technology will also be developed for the servicing of satellites at the Space Station, system monitoring and diagnosis, space manufacturing, and the assembly of large space structures

Structural Analysis of Masonry Historical Constructions. Classical and Advanced Approaches

A review of methods applicable to the study of masonry historical construction, encompassing both classical and advanced ones, is presented. Firstly, the paper offers a discussion on the main challenges posed by historical structures and the desirable conditions that approaches oriented to the modeling and analysis of this type of structures should accomplish. Secondly, the main available methods which are actually used for study masonry historical structures are referred to and discussed. The main available strategies, including limit analysis, simplified methods, FEM macro- or micro-modeling and discrete element methods (DEM) are considered with regard to their realism, computer efficiency, data availability and real applicability to large structures. A set of final considerations are offered on the real possibility of carrying out realistic analysis of complex historic masonry structures. In spite of the modern developments, the study of historical buildings is still facing significant difficulties linked to computational effort, possibility of input data acquisition and limited realism of methods

Performance of Wind Exposed Structures

PERBACCO (a free Italian acronym for Life-cycle Performance, Innovation and Design Criteria for Structures and Infrastructures Facing Æolian and Other Natural Hazards) is a research project partly funded by the Italian Ministry for University (MIUR) in the PRIN (Progetti di Ricerca di Interesse Nazionale) framework, for the years 2004-05.Within the project, a first attempt has been made to integrate different disciplines aiming at an overall optimization of the performance of a wide range of wind exposed structures and infrastructures, with consequent benefi cial impact on the society.The overall objectives were (a) to provide unifi ed concepts for "expected performance" and "risks induced by æolian and other natural hazards", to be applied to structures and infrastructures over their whole life-cycle, such to be acceptable to stakeholders in the construction process (i.e. from the owner to the end-user), (b) to provide models and methodologies for dynamic monitoring of the performance of structures and infrastructures, to be integrated in appropriately designed procedures, and (c) to collect, refi ne, fi le and disseminate the knowledge available on a European basis, concerning the performance of wind-exposed structures and facilities, in a way such to be of use to Construction Industry. This volume summarises the main results obtained during the Project, with each Section addressing a different class of problems, to which many research Units have contributed. A list of papers containing the main results of the research activities carried out within the Project is also provided in each Section