Uncertainty in Structural Engineering

Bulleit, William M.

doi:10.1061/(asce)1084-0680(2008)13:1(24)

Cited by 70 publications

(25 citation statements)

References 7 publications

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“…According to the Probabilistic Model Code of the Joint Committee on Structural Safety JCSS, model uncertainty should describe random effects neglected in the model and simplifications in mathematical relations on which the model is based. Bulleit viewed model uncertainty as a measure of “how the model fits to test data” and “how the model predicts structural behaviour”; see also Reference .…”

Section: Uncertainty In Resistance Modelsmentioning

confidence: 99%

Uncertainty in shear resistance models of reinforced concrete beams according to fib MC2010

Sýkora

Krejsa

Mlčoch

et al. 2018

Structural Concrete

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Load bearing capacity can be predicted by appropriate modeling of material properties, geometry variables, and uncertainties associated with an applied model for the failure mechanism under consideration. The submitted study investigates shear resistance model uncertainties for reinforced concrete beams with and without shear reinforcement, considering large test databases and various levels of approximation offered by fib Model Code 2010. Model uncertainty is treated as a random variable and its characteristics are obtained by comparing test and model outcomes. The sensitivity of model uncertainty with respect to basic variables is analyzed. For beams with stirrups, Level III is recommended for practical applications. Its predictions are shown to be independent of the amount of shear reinforcement and have reasonable bias and dispersion around test results. For beams without shear reinforcement, the use of Level II is advisable and a distinction between lightly reinforced and moderately to heavily reinforced beams should be made. K E Y W O R D S fib model code 2010, model uncertainty, partial factor, reinforced concrete, shear reinforcement, shear resistance 1 | INTRODUCTIONAdequate description of the uncertainties in resistance models was recognized as one of key issues in reliability investigations of new and existing reinforced concrete (RC) structures. 1 Particularly when description of load effects and structural responses is highly complex, and operational procedures are based on simplified approaches, model uncertainty may dominate structural reliability and its quantification and explicit inclusion in reliability analysis is required. 2 Such cases can be identified by the lack of consensus amongst experts; alternative models used in research studies and practical applications; and different levels of approximation (LoA) 3 introduced in design codes. This is the case with shear resistances of RC structures, recognizing that shear strengths predicted by different design codes for a particular beam or section can vary by factors of more than two. 4 Shear resistances of beams have stimulated an extensive debate over recent decades, as there is not yet an international consensus on which variables are important, 5 which mechanisms govern 6,7 and how to codify existing understanding. 8 Features of several models for shear resistances of beams with and without special shear reinforcement (hereafter referred to as "shear models" for brevity) were investigated and improvements proposed. [9][10][11][12][13][14][15] The complexity of shear transfer actions and modeling was recognized and described in detail in References 16,17.Model uncertainty as an indicator of the difference between model and real structural resistances was explicitly addressed by Russo et al 10 who analyzed the uncertainty associated with the models in EN 1992-1-1 18 and American Concrete Institute (ACI) 318M-08. 19 Bentz et al 4 were focused on the ACI procedure and two approaches belonging to the Modified Compression Field Theory. The recent

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Section: Uncertainty In Resistance Modelsmentioning

confidence: 99%

Uncertainty in shear resistance models of reinforced concrete beams according to fib MC2010

Sýkora

Krejsa

Mlčoch

et al. 2018

Structural Concrete

View full text Add to dashboard Cite

show abstract

“…In general, the uncertainties in structural engineering can be classified in two families: aleatory and epistemic [19]. The aleatory uncertainties concern the intrinsic randomness of the variables that governs a specific structural problem, whereas the epistemic uncertainties are mainly related to the lack of knowledge in the definition of the structural model [19], [23]- [25] and sometimes represented also by auxiliary non-physical variables/choices [19]. The safety assessment of a structural system by means of NLFEAs should account for explicitly both these sources of uncertainty.…”

Section: Resistance Model Uncertainties For Nlfeasmentioning

confidence: 99%

Assessment of the Resistance Model Uncertainties in Plane Stress Nlfea of Cyclically Loaded Reinforced Concrete Systems

Gino¹,

Castaldo²,

Dorato³

et al. 2019

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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The present work is devoted to estimate the resistance model uncertainty within plane stress non-linear finite element analyses (NLFEAs) of reinforced concrete structures subjected to cyclic loads. Specifically, various shear walls experimentally tested are considered for the investigation. The comparison between the plane stress NLFE structural model results and the experimental outcomes is carried out considering the possible modelling hypotheses available to describe the mechanical behaviour of reinforced concrete members subjected to cyclic loads. Several NLFE structural models are defined for each experimental test in order to investigate the resistance model uncertainty.

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“…During the last decades, the engineering community acknowledged the importance of uncertainties on the performance of structures and engineering systems in general (Jensen and Iwan, 1992;Bulleit, 2008). Uncertainty quantification provides metrics to study the relationship between imprecisely prescribed model inputs and the model's predictions (Papadrakakis et al, 2005).…”

Section: Modeling Of Uncertaintiesmentioning

confidence: 99%

Computational Structural Engineering: Past Achievements and Future Challenges

Plevris

Tsiatas

2018

Front. Built Environ.

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PAST ACHIEVEMENTS AND CURRENT TRENDSComputational methods are computer-based methods used to numerically solve mathematical models that describe physical phenomena. The purpose of computational modeling is to study the behavior of complex systems by means of computer simulations and it can be used to make predictions of the system's behavior under different conditions, often for cases in which intuitive analytical solutions are not available (Nature, 2018). Computational methods have emerged in engineering during the 1960s. Since then, structural engineers have been leaders in technological solutions to engineering analysis and design problems. The evolution of electronic computers together with the tremendous increase of computational power has triggered the continuous development of computational methods. Rapid advances in computer hardware have had a profound effect on various engineering disciplines. The applications are numerous and cover a broad field of engineering branches including civil, mechanical, naval, electrical, aerospace, material, biomolecular, among others. Computational structural engineering has evolved as an insightful blend combining both structural analysis and computer science.Among all computational methods, the Finite Element Method (FEM) and the Boundary Element Method (BEM) are the most prevalent ones. Both methods exhibit unique characteristics as well as advantages and disadvantages. The FEM, as a simulation tool, enables sophisticated methods of computational mechanics, computer technology and applied mathematics. It has been broadly adopted in scientific research and engineering applications and it can be considered as the most popular method used for structural analysis, tackling linear and nonlinear problems of systems with various geometries, material properties and loads (Reddy, 2005). In FEM, the solution domain is subdivided into a finite number of elements. Each element approximately reproduces the behavior of a small region of the body it represents, but continuity between the elements is only enforced in an overall minimum energy sense. The FEM is especially suitable for problems with complex geometries, but the whole-body discretization scheme that is utilized inevitably leads to a large number of finite elements and, thus, increased computational cost. Although Professor R. Clough coined the term "Finite Element Method" in his pioneer work dated back in 1960 (Clough, 1960), the answer to the question "who invented FEM in everyday use?" is possibly M. Jonathan (Jon) Turner at Boeing who generalized and perfected the Direct Stiffness Method, and convinced his company to commit resources to it, over the period 1952 -1964(Felippa, 2017. The FEM obtained its real impetus in the 1960s and 1970s by the developments of pioneers J. H. Argyris, R. W. Clough, H. C. Martin, O. C. Zienkiewicz and their co-workers who evolved the method and applied it to a wide range of structural problems and applications.In the years since its first use, FEM has grown and developed into a standard...

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Uncertainty in Structural Engineering

Cited by 70 publications

References 7 publications

Uncertainty in shear resistance models of reinforced concrete beams according to fib MC2010

Uncertainty in shear resistance models of reinforced concrete beams according to fib MC2010

Assessment of the Resistance Model Uncertainties in Plane Stress Nlfea of Cyclically Loaded Reinforced Concrete Systems

Computational Structural Engineering: Past Achievements and Future Challenges

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