Numerical Bayesian updating of prior distributions for concrete strength properties considering conformity control

Caspeele, Robby,Taerwe, Luc Techno-Press 2013 Advances in concrete construction Vol.1 No.1

Prior concrete strength distributions can be updated by using direct information from test results as well as by taking into account indirect information due to conformity control. Due to the filtering effect of conformity control, the distribution of the material property in the accepted inspected lots will have lower fraction defectives in comparison to the distribution of the entire production (before or without inspection). A methodology is presented to quantify this influence in a Bayesian framework based on prior knowledge with respect to the hyperparameters of concrete strength distributions. An algorithm is presented in order to update prior distributions through numerical integration, taking into account the operating characteristic of the applied conformity criteria, calculated based on Monte Carlo simulations. Different examples are given to derive suitable hyperparameters for incoming strength distributions of concrete offered for conformity assessment, using updated available prior information, maximum-likelihood estimators or a bootstrap procedure. Furthermore, the updating procedure based on direct as well as indirect information obtained by conformity assessment is illustrated and used to quantify the filtering effect of conformity criteria on concrete strength distributions in case of a specific set of conformity criteria.

Strain and crack development in continuous reinforced concrete slabs subjected to catenary action

Gouverneur, Dirk,Caspeele, Robby,Taerwe, Luc Techno-Press 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.1

Several structural calamities in the second half of the 20th century have shown that adequate collapse-resistance cannot be achieved by designing the individual elements of a structure without taking their interconnectivity into consideration. It has long been acknowledged that membrane behaviour of reinforced concrete structures can significantly increase the robustness of a structure and delay a complete collapse. An experimental large-scale test was conducted on a horizontally restrained, continuous reinforced concrete slab exposed to an artificial failure of the central support and subsequent loading until collapse of the specimen. Within this investigation the development of catenary action associated with the formation of large displacements was observed to increase the ultimate load capacity of the specimen significantly. The development of displacements, strains and horizontal forces within this investigation confirmed a load transfer process from an elastic bending mechanism to a tension controlled catenary mechanism. In this contribution a special focus is directed towards strain and crack development at critical sections. The results of this contribution are of particular importance when validating numerical models related to the development of catenary action in concrete slabs.

Bayesian updated correlation length of spatial concrete properties using limited data

Pieterjan Criel,Robby Caspeele,Luc Taerwe 사단법인 한국계산역학회 2014 Computers and Concrete, An International Journal Vol.13 No.5

A Bayesian response surface updating procedure is applied in order to update the parameters of the covariance function of a random field for concrete properties based on a limited number of available measurements. Formulas as well as a numerical algorithm are presented in order to update the parameters of response surfaces using Markov Chain Monte Carlo simulations. The parameters of the covariance function are often based on some kind of expert judgment due the lack of sufficient measurement data. However, a Bayesian updating technique enables to estimate the parameters of the covariance function more rigorously and with less ambiguity. Prior information can be incorporated in the form of vague or informative priors. The proposed estimation procedure is evaluated through numerical simulations and compared to the commonly used least square method.

Strain and crack development in continuous reinforced concrete slabs subjected to catenary action

Dirk Gouverneur,Robby Caspeele,Luc Taerwe 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.1

Several structural calamities in the second half of the 20th century have shown that adequatecollapse-resistance cannot be achieved by designing the individual elements of a structure without taking their interconnectivity into consideration. It has long been acknowledged that membrane behaviour of reinforced concrete structures can significantly increase the robustness of a structure and delay a complete collapse. An experimental large-scale test was conducted on a horizontally restrained, continuous reinforced concrete slab exposed to an artificial failure of the central support and subsequent loading until collapse of the specimen. Within this investigation the development of catenary action associated with the formation of large displacements was observed to increase the ultimate load capacity of the specimen significantly. The development of displacements, strains and horizontal forces within this investigation confirmed a load transfer process from an elastic bending mechanism to a tension controlled catenary mechanism. In this contribution a special focus is directed towards strain and crack development at critical sections. The results of this contribution are of particular importance when validating numerical models related to the development of catenary action in concrete slabs.

Mechanical properties of curved composite box girders with corrugated steel webs

Sumei Liu,Wouter De Corte,Hanshan Ding,Luc Taerwe 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.1

Several methods derived for use on traditional concrete curved box girders (CBGs) are used in design practice. However, these typically consider only one elastic modulus and one shear modulus, and consequently cannot be applied directly to CBGs with corrugated steel webs (CSWs) due to the large shear deformations and small longitudinal stiffness of CSWs, while these shear deformations are small and usually ignored for common concrete webs. In this paper, firstly, the flexure-torsion governing differential equations considering the shear deformations and the accordion effect of CSWs, and the distortion governing differential equation considering the accordion effect of CSWs are derived for CBGs with CSWs. A practical method which can solve the deflections, torsional angles, distortional angles, stresses and internal forces of simple and continuous CBGs with intermediate diaphragms is proposed. Secondly, the results of a series of tests performed on three CBGs with CSWs, published test results, as well as finite element analysis results and theoretical results of straight box girders (SBGs) with CSWs are used to verify the correctness of the analytical method. The agreement between analytical, experimental and numerical results is good. Finally, a parametric analysis is conducted and the results show that: (a) the influence of shear deformations of CSWs on the deflections of CBGs with CSWs increases with increasing curvature radius R. For SBGs with CSWs, the deflections may increase by 30% when considering shear deformations. For CBGs with CSWs, the deflection increase ranges between 8% and 30% for concentrated loads depending on the curvature radius. (b) the distortional shear stress, which is small and typically neglected for CBGs with concrete webs, may be as big as, or larger than the flexural shear stress, and must be considered. The restrained torsional shear stress, which is also small and typically neglected for CBGs with concrete webs, can reach 9% of the flexural shear stress, and also must be considered.