References of "Franssen, Renaud"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailResponse simulation of UHPFRC members
Franssen, Renaud ULiege; Guner, Serhan; Courard, Luc ULiege et al

in Unknown (in press)

Ultra-high-performance fiber-reinforced concrete (UHPFRC) is a new generation material with outstanding mechanical properties and excellent durability. The uses of UHPFRC have, however, been mostly ... [more ▼]

Ultra-high-performance fiber-reinforced concrete (UHPFRC) is a new generation material with outstanding mechanical properties and excellent durability. The uses of UHPFRC have, however, been mostly limited to demonstration applications and research projects, due to its perceived high cost and the lack of proven analysis procedures. In the past decade, new design provisions have been proposed in France, Switzerland, Japan, and Australia while a proven numerical modeling approach is still missing. As an effort to contribute to bridging this gap, a numerical modeling approach is established in this research for UHPFRC members. The approach is based on the Diverse Embedment Model within the global framework of the Disturbed Stress Field Model, a smeared rotating-crack formulation for 2D modeling of concrete structures. This study aims to capture the behavior of UHPFRC by using only a few input parameters. The established model is validated with large-scale tests of UHPFRC beams from the literature. The beams considered incorporate various cross-section and reinforcement details, and exhibit a range of failure modes including flexure and shear. The validation studies, based on comparisons with the experimental results, demonstrate that the proposed modeling approach provides accurate response simulations through simple models with short analysis times. [less ▲]

Detailed reference viewed: 36 (20 ULiège)
Full Text
Peer Reviewed
See detailA study on the numerical modelling of UHPFRC-strengthened members
Franssen, Renaud ULiege; Guner, Serhan; Courard, Luc ULiege et al

in Alexander, M. G.; Beushausen, Hans; Dehn, F (Eds.) et al International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) (2018)

The maintenance of large aging infrastructure across the world creates serious technical, environmental, and economic challenges. Ultra-high performance fibre-reinforced concretes (UHPFRC) are a new ... [more ▼]

The maintenance of large aging infrastructure across the world creates serious technical, environmental, and economic challenges. Ultra-high performance fibre-reinforced concretes (UHPFRC) are a new generation of materials with outstanding mechanical properties as well as very high durability due to their extremely low permeability. These properties open new horizons for the sustainable rehabilitation of aging concrete structures. Since UHPFRC is a young and evolving material, codes are still either lacking or incomplete, with recent design provisions proposed in France, Switzerland, Japan, and Australia. However, engineers and public agencies around the world need resources to study, model, and rehabilitate structures using UHPFRC. As an effort to contribute to the efficient use of this promising material, this paper presents a new numerical modelling approach for UHPFRC-strengthened concrete members. The approach is based on the Diverse Embedment Model within the global framework of the Disturbed Stress Field Model, a smeared rotating-crack formulation for 2D modelling of reinforced concrete structures. This study presents an adapted version of the DEM in order to capture the behaviour of UHPFRC by using a small number of input parameters. The model is validated with tension tests from the literature and is then used to model UHPFRC-strengthened elements. The paper will discuss the formulation of the model and will provide validation studies with various tests of beams, columns and walls from the literature. These studies will demonstrate the effectiveness of the proposed modelling approach. [less ▲]

Detailed reference viewed: 45 (19 ULiège)
Full Text
Peer Reviewed
See detailThree-parameter kinematic approach for shear behaviour of short coupling beams with conventional reinforcement
Mihaylov, Boyan ULiege; Franssen, Renaud ULiege

in fib Bulletins (2018), 85

This paper presents a three-parameter kinematic theory (3PKT) for predicting the shear strength and deformation patterns of short coupling beams. The 3PKT approach is situated between simple and ... [more ▼]

This paper presents a three-parameter kinematic theory (3PKT) for predicting the shear strength and deformation patterns of short coupling beams. The 3PKT approach is situated between simple and conservative strut-and-tie models and complex nonlinear finite element (FE) models. It is aimed at improving the strength predictions of strut-and-tie models while maintaining relative simplicity and clear physical basis. In addition, it is aimed at providing estimates of the ultimate deformations in coupling beams which are typically calculated with FE models. While FE models use a large number of degrees of freedom (DOFs) to describe the deformation patterns in coupling beams, the 3PKT is based on a kinematic model with only three DOFs. In addition to kinematic conditions, the 3PKT also includes equilibrium equations and constitutive relationships for the mechanisms of shear resistance in short coupling beams. The paper presents the formulation of the 3PKT and compares its shear strength predictions to results from tests, FE simulations, and strut-and-tie models based on the fib Model Code 2010. It is shown that the 3PKT approximates well the predictions of the FE models while the strut-and-tie model produces significantly lower strengths. [less ▲]

Detailed reference viewed: 59 (22 ULiège)
Full Text
Peer Reviewed
See detailMacro-Kinematic Approach for Shear Behaviour of Short Coupling Beams with Conventional Reinforcement
Mihaylov, Boyan ULiege; Franssen, Renaud ULiege

Conference (2017, June 13)

Short coupling beams in wall structures work predominantly in shear and develop complex deformation patterns. For this reason they cannot be modelled based on the classical plane-sections-remain-plane ... [more ▼]

Short coupling beams in wall structures work predominantly in shear and develop complex deformation patterns. For this reason they cannot be modelled based on the classical plane-sections-remain-plane hypothesis, and are typically designed with strut-and-tie models. However, because strut-and-tie models are inherently conservative, they can result in very large amounts of shear reinforcement (stirrups), and therefore significant construction difficulties. In addition, strut-and-tie models do not provide information about the deformation capacity of coupling beams, which is important for performance-based seismic design. To address these challenges, this paper discusses a three-parameter kinematic theory (3PKT) for the shear strength and deformation patterns of short coupling beams. The 3PKT approach is situated between simple and conservative strut-and-tie models and complex non-linear finite element (FE) models. While FE models use a large number of degrees of freedom (DOFs) to describe the deformation patterns in coupling beams, the 3PKT method is based on a kinematic model with only three DOFs. The paper presents the formulation of the model and its validation with tests. [less ▲]

Detailed reference viewed: 69 (27 ULiège)
Full Text
Peer Reviewed
See detailShear-flexure interaction in the critical sections of short coupling beams
Mihaylov, Boyan ULiege; Franssen, Renaud ULiege

in Engineering Structures (2017)

Heavily-loaded short coupling beams with large amounts of transverse reinforcement fail in sliding shear or diagonal compression under the complex interaction between shear and flexure. These failure ... [more ▼]

Heavily-loaded short coupling beams with large amounts of transverse reinforcement fail in sliding shear or diagonal compression under the complex interaction between shear and flexure. These failure modes often occur after yielding of the flexural reinforcement and limit the displacement capacity of the member. To study such failures, this paper compares experimental results with predictions of models with various levels of complexity. It is shown that complex nonlinear finite element models (FEM) can capture adequately the entire behaviour of short coupling beams, while the classical flexural model produces unconservative strength predictions. It is also shown that strut-and-tie models are reasonably conservative provided that their geometry is selected to maximize the strength predictions. To produce similarly adequate strength predictions as those of the FEM – while at the same time maintaining the simplicity of the flexural model – the paper proposes a mechanical model based on strain compatibility. The main assumption of the model links the principal compressive strains in the critical section to the longitudinal strains in the tension zone. It is shown that the model captures well the effect of different test variables on the shear strength. When applied to a database of 24 tests, the model produced an average shear strength experimental-to-predicted ratio of 1.12 with a coefficient of variation of 8.4%. [less ▲]

Detailed reference viewed: 56 (27 ULiège)