"Design and assessment criteria for safety and cost efficiency"
A rational basis for the specification of reliability requirements for design and assessment of structures is introduced and discussed in this lecture. It is thereby focused on the challenges related to the practical application of reliability requirements and aspects of standardization.
by Prof. Jochen Köhler from NTNU.
Monitoring and auscultation
From sensors to useful signals for concrete evaluation and monitoring
Before getting any observable from a measurement, signals have to be recorded after a wave or field has been interacting with concrete. The participants will get an overview of signal sampling and acquisition main features together with an insight of signal processing in the time and frequency domains. Notions about interferometry will be provided in relation to ultrasonic and fibre optic measurements.
Lecturer: Dr Odile Abraham (Université Gustave Eiffel, Ifsttar)
From signals to useful parameters: combination and data fusion
NDT parameters are not necessarily directly related to material or structural parameters. They have to be translated. An overview on calibration, combination of methods/data fusion to improve the results will be given.
Lecturer: Dr Ernst Niederleithinger (BAM)
Probability of Detection (PoD), Receiver Operating Characteristic (ROC)
How to connect parameters from NDT and monitoring to reliability and probability assessment? Studies on structural reliability or asset management are based more and more on risk assessment. To include NDT and monitoring data into this framework, their reliability must be known. The basic tools to do so, probability of detection and receiver operating characteristic curves will be explained.
Lecturer: Dr Ernst Niederleithinger (BAM)
Demonstrations and exercises on monitoring and auscultation
Group on Fibre Optics: How to size a crack ?
The advantages of fibre optics to monitor temperature and deformation as well as crack opening will be illustrated through various on-site and laboratory experiments. Knowledge and understanding of the transfer function required to recover quantitative information about crack opening will be provided. A lab demonstration will be carried out.
Group on CWI: Coda wave interferometry a new very sensitive monitoring tool for concrete.
The scattering and reverberation of ultrasonic waves in concrete structure, often viewed as noise in conventional NDT/SHM, is shown here to be of great value to get information on early age damages invisible otherwise. The participants will get to know the basic of CWI signal processing as well as a description about the present state of the art of experimental set-ups with embedded or external sensors. Environmental bias will be highlighted and ways to remove them addressed. The participants will process of the data from a controlled experiment on a beam under loading test.
Structural and action models
Calibration of partial factor design formats - best practice and challenges
Structural design standards are used for the daily design of structures. They comprise of simple rules that represent the current best practice and are generally applied to regular structures. Structural design standards do not account for risk, reliability and uncertainty in an explicit manner. However, the safety concept that is implemented is taking reference to uncertainty and reliability implicitly in terms of partial safety factors and characteristic values.
In this short-course, it is demonstrated that structural design standards correspond to the societal preference for safety and cost effectiveness. A direct correspondence between reliability and the choice of partial safety factors is developed for particular cases. However, it is also shown that the set up of structural design codes is merely a problem of proper generalisation and simplification.
Lecturer: Jochen Köhler (NTNU)
Assessment of extreme values of effects in structures
The assessment of extreme values of effects in structures will be based on extreme value theory and use of temporal series (coming either from monitoring or calculations). A short overview of statistics of standards will be made (review periods and return values), explanation of extreme value theory and some examples of application. The exercices will be made with R project, based on monitoring data.
Lecturer: Franziska Schmidt (Université Gustave Eiffel, Ifsttar)
Deterministic and probabilistic approaches of fatigue of steel structures
Introduction of fatigue phenomenon, welded details in steel bridges
Miner model and S-N (Woehler) curves
Fracture mechanics and propagation law
Probabilistic model of fatigue
Damage calculation, reliability index
Appications to composite bridges and orthoropic decks
Lecturer: Bernard Jacob (Université Gustave Eiffel, Ifsttar)
Reliability, risk and decision analyses
Uncertainty and structural reliability assessment
The lecture of uncertainty and structural reliability assessment contains the fundamentals of uncertainty modelling in civil engineering and the methods of structural reliability and structural system reliability analysis. The uncertainty modelling provides the types of uncertainties and the approaches to model these in a structural reliability analysis. Methods for structural reliability analyses like Monte Carlo Simulation and FORM are introduced and their application in a structural system reliability analysis is demonstrated.
Lecturer: Prof. John Dalsgaard Sørensen (AAU)
Decision and structural information analyses
The lecture on decision and structural information analyses provides a summary on decision scenario development, decision modelling and analysis methods encompassing prior, pre-posterior, posterior decision and value of information analysis in the context of structural health information for civil engineering structures. Building upon the structural reliability methods and uncertainty modelling methods, the lecture provides models for structural health information and actions such as non-destructive testing results, monitoring, load testing, load control and repair.
Lecturer: Prof. Sebastian Thöns (Lund University)