Finite volume analysis of reinforced concrete structure cracking using a thermo-plastic-damage model

This paper proposes modifications to the phenomenological model formulation called CDPM2, developed by Grassl et al. [1]. The proposed modifications are designed to enhance model performance with coupling to temperature effects. A very strong coupling between nonlinear elasticity, plasticity, nonlocal damage evolution and temperature gradient is used to simulate arbitrary crack propagation. The use of FVM to model solid damage is a numerical challenge. This approach presents some advantages such as: ensuring that discretization is conservative even when the geometry is changing; providing a simple formulation that can be obtained directly from a difference method; and employing unstructured meshes. Most authors have neglected the nonlinearity of concrete in the elastic domain from the start of loading to the plastic domain. In this paper we confirm that concrete rheology is not linear even under low loading. Also, since the so-called fracture energy is a key parameter needed to determine the size of cracks and how they propagate in space, we consider that the fracture energy is both material and geometrical parameter dependent. For this reason, we developed a new approach which includes adaptive mesh, nonlinear rheology and thermal effects to re-calculate fracture energy at each time step. Many authors use a constant value obtained from experiments to calculate fracture energy; others use a numerical correlation. In this study, the fracture energy parameter is not constant and can vary with temperature or/and with a change in geometry due to concrete failure. As is well known, the mesh quality of complex geometries is very important for making accurate predictions. A new meshing tool was developed using the C++ programming language. This tool is faster, more accurate and produces a high-quality structured mesh. The predictions obtained were compared to a wide variety of experimental data and showed good agreement

3D virtual laboratory for geotechnical applications: another perspective

Discrete element methods are important tools for investigating the mechanics of granular materials. In two dimensions, the reliability of these numerical approaches is increasingly being challenged, because they cannot take into account all the factors involved in the behavior of a granular medium. With new concepts, such as high performance parallel computing and 3D visualization, it is now possible to conduct numerical simulations of granular materials made up of several thousands of particles, and also to follow the evolution of the various parameters involved in the behavior of a granular medium. Experimental tests have been carried out to validate the results obtained by using a virtual laboratory. This paper presents the earlier results obtained in our 3D Virtual Laboratory on the response of specimens of glass beads of uniform size during shear tests. Good agreement was achieved between the virtual simulations and the experimental tests. This work highlights the possibility of using a new 3D virtual laboratory for dynamic simulation. This approach could be of significant value in improving the verification, validation, and communication of the simulation results of discrete element methods, which can in turn make the simulations more credible and thus useful in decision making

3D virtual laboratory for geotechnical applications: another perspective

Discrete element methods are important tools for investigating the mechanics of granular materials. In two dimensions, the reliability of these numerical approaches is increasingly being challenged, because they cannot take into account all the factors involved in the behavior of a granular medium. With new concepts, such as high performance parallel computing and 3D visualization, it is now possible to conduct numerical simulations of granular materials made up of several thousands of particles, and also to follow the evolution of the various parameters involved in the behavior of a granular medium. Experimental tests have been carried out to validate the results obtained by using a virtual laboratory. This paper presents the earlier results obtained in our 3D Virtual Laboratory on the response of specimens of glass beads of uniform size during shear tests. Good agreement was achieved between the virtual simulations and the experimental tests. This work highlights the possibility of using a new 3D virtual laboratory for dynamic simulation. This approach could be of significant value in improving the verification, validation, and communication of the simulation results of discrete element methods, which can in turn make the simulations more credible and thus useful in decision making

Finite volume analysis of reinforced concrete structure cracking using a thermo-plastic-damage model

This paper proposes modifications to the phenomenological model formulation called CDPM2, developed by Grassl et al. [1]. The proposed modifications are designed to enhance model performance with coupling to temperature effects. A very strong coupling between nonlinear elasticity, plasticity, nonlocal damage evolution and temperature gradient is used to simulate arbitrary crack propagation. The use of FVM to model solid damage is a numerical challenge. This approach presents some advantages such as: ensuring that discretization is conservative even when the geometry is changing; providing a simple formulation that can be obtained directly from a difference method; and employing unstructured meshes. Most authors have neglected the nonlinearity of concrete in the elastic domain from the start of loading to the plastic domain. In this paper we confirm that concrete rheology is not linear even under low loading. Also, since the so-called fracture energy is a key parameter needed to determine the size of cracks and how they propagate in space, we consider that the fracture energy is both material and geometrical parameter dependent. For this reason, we developed a new approach which includes adaptive mesh, nonlinear rheology and thermal effects to re-calculate fracture energy at each time step. Many authors use a constant value obtained from experiments to calculate fracture energy; others use a numerical correlation. In this study, the fracture energy parameter is not constant and can vary with temperature or/and with a change in geometry due to concrete failure. As is well known, the mesh quality of complex geometries is very important for making accurate predictions. A new meshing tool was developed using the C++ programming language. This tool is faster, more accurate and produces a high-quality structured mesh. The predictions obtained were compared to a wide variety of experimental data and showed good agreement

Use of fibre reinforced polymer reinforcement integrated with fibre optic sensors for concrete bridge deck slab construction

The use of corrosion free fibre reinforced polymer (FRP) composites as reinforcement to concrete is currently being seen as a promising option to generate durable concrete structures. However, there exists very little credible information about its field application and performance. This paper describes the Joffre Bridge project, in Sherbrooke (Qu\ue9bec, Canada), over the St-Fran\ue7ois River, where Carbon Fibre Reinforced Polymer (CFRP) was used as reinforcement for a portion of the concrete deck slab. The bridge consists of five longitudinal spans with lengthsvarying from 26 to 37 m. Each span has a concrete deck supported by five steel girders at 3.7 m. A part of the concrete deck slab (7.3 7 11.5 m) and a portion of the traffic barrier and the sidewalk were reinforced with Carbon (CFRP) and Glass Fibre Reinforced Polymer (GFRP) reinforcement. The bridge was extensively instrumented with many different types of gauges, including integrated fibre optic sensors (FOS) into FRP reinforcement. The performance of the bridge had been assessed under static and dynamic loading using calibrated heavy trucks. Moreover, structural design and construction details of the bridge and instrumentation were performed. The results from calibrated field tests on the bridge are presented in this paper.L'utilisation de composites, non sujet \ue0 la corrosion, en polym\ue8re renforc\ue9 de fibres (PRF) en tant que renfort du b\ue9ton sont vus comme une option prometteuse pour g\ue9n\ue9rer des structures de b\ue9ton durables. Cependant, il existe tr\ue8s peu d'informations cr\ue9dibles \ue0 propos de leur application et performance sur le terrain. Cet article d\ue9crit leprojet du pont Joffre, \ue0 Sherbrooke (Qu\ue9bec, Canada), au-dessus de la rivi\ue8re Saint-Fran\ue7ois, o\uf9 un polym\ue8re renforc\ue9 de fibres de carbone (PRFC) a \ue9t\ue9 utilis\ue9 en tant que renfort pour une portion de la dalle en b\ue9ton du tablier. Le pont consiste en cinq trav\ue9es longitudinales dont la longueur varie de 26 \ue0 37 m. Chaque trav\ue9e a un tablier de b\ue9ton support\ue9 par cinq poutres d'acier \ue0 3,7 m. Une partie du tablier de pont (7,3 7 11,5 m), et une portion de la barri\ue8re de circulation et du trottoir ont \ue9t\ue9 renforc\ue9es avec du polym\ue8re renforc\ue9 de fibre de carbone (PRFC) et de verre (PRFV). Le pont a \ue9t\ue9 largement instrument\ue9 avec diff\ue9rents types de jauges, incluant des senseurs \ue0 fibres optiques (SFO) \ue0 l'int\ue9rieur du renforcement en PRF. La performance du pont a \ue9t\ue9 \ue9valu\ue9e sous des chargements statiques et dynamiques par l'utilisation de camions lourds calibr\ue9s. De plus, la conception structurale et les d\ue9tails de construction du pont et de l'instrumentation ont \ue9t\ue9 accomplis. Les r\ue9sultats provenant de tests calibr\ue9s sur le terrain pour le pont sont pr\ue9sent\ue9s dans cet article.Peer reviewed: YesNRC publication: Ye

Effect of the temperature on the water transport by capillarity into the concrete porosity

This paper presents a new 2D water transport model considering capillary suction to predict the water content evolution in the concrete porosity. The basic formulations of the model are illustrated, and a switching algorithm is introduced to simulated wet-drying effects. Two specific absorption tests are studied to validate this model. The first test conducted under room temperature allows to observe that capillary effects play an important role in the concrete material sorptivity and this phenomenon was well captured by the numerical model. The second test conducted under different temperatures highlight that temperature has significant effect on the capillary suction process and it has been considered in the model as an important input parameter