Numerical modeling approach for UHPFRC members including crack spacing formulations

Franssen, Renaud; Güner, Serhan; Courard, Luc; Mihaylov, Boyan

doi:10.1016/j.engstruct.2021.112179

Cited by 6 publications

(3 citation statements)

References 14 publications

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“…This model is adopted here for the fibers in the UHPFRC jackets with one modification: the bond stress τ f,max is increased to 0.75√f Uc 0 to account for the stronger cement matrix of UHPFRC compared with regular concrete. 13 In addition, the crack width w is replaced by the crack displacement W = √(w 2 + s 2 ) to account for the slip displacement in the crack.…”

Section: Tension In Fibers Across the Critical Crackmentioning

confidence: 99%

“…To derive such an expression, it is proposed to start from an existing equation for crack spacing in members F I G U R E 7 Modeling the tension in the fibers in ultra highperformance fiber-reinforced concrete jackets across the critical diagonal crack-Photo from specimen RF50r after failure with pulled-out fibers built entirely of UHPHRC and reinforcement (reinforced UHPFRC or R-UHPFRC members). Such an equation was derived elsewhere 13 based on the free-body diagram illustrated in Figure 8a. This diagram shows the equilibrium of a concrete region bound between two sections: that of an existing crack (right) and the closest section where a new crack can form (left).…”

Section: Crack Controlmentioning

confidence: 99%

“…The SDEM focuses on a pure opening of the crack (Mode I) and links the stress across the crack to the crack width w according to:

σ_{normalf} = α_{normalf} V_{normalf} K_{st} τ_{f, \max} \frac{l_{f}}{d_{f}} {((), 1 goodbreak- \frac{2 w}{l_{normalf}})}^{2}, MPa

K_{st} = \{\begin{matrix} \frac{β_{f}}{3} \frac{w}{s_{f}} for w < s_{normalf} \\ 1 - \sqrt{\frac{{normals}_{normalf}}{w}} + \frac{β_{f}}{3} \sqrt{\frac{s_{normalf}}{w}} for w \geq s_{normalf} \end{matrix}

where α f ≈ 0.5 is a fiber orientation factor, V f is the volumetric ratio of the fibers, l f and d f are the fiber length and diameter, τ f,max = 0.396√ f c ′ (MPa) is the bond stress between the fibers and the concrete, β f = 0.67 and s f = 0.01 mm. This model is adopted here for the fibers in the UHPFRC jackets with one modification: the bond stress τ f,max is increased to 0.75√ f Uc ′ to account for the stronger cement matrix of UHPFRC compared with regular concrete 13 . In addition, the crack width w is replaced by the crack displacement W = √( w 2 + s 2 ) to account for the slip displacement in the crack.…”

Section: Modeling Of Uhpfrc Jacketsmentioning

confidence: 99%

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Modeling the behavior of shear‐dominated walls retrofitted with ultra high‐performance fiber‐reinforced concrete jackets

Mihaylov

Franssen

2022

Structural Concrete

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Large-scale tests of shear-dominated walls with ultra high-performance fiberreinforced concrete (UHPFRC) jackets have shown the high effectiveness of this retrofitting solution. The jackets can suppress brittle shear failures and result in a ductile response governed by yielding of the flexural reinforcement.In addition, due to the low porosity of UHPFRC and the crack control provided by the fibers, the jackets can also provide an effective corrosion protection. However, while this retrofitting solution is very promising, there is a lack of mechanical models that can predict the effect of UHPFRC jackets. This paper proposes such a model based on a three-parameter kinematic theory (3PKT) for reinforced concrete walls. The 3PKT is extended by modeling three important effects associated with the UHPFRC jackets: tension in the fibers across the critical diagonal cracks, increased compression resistance of the critical loading zones, and enhanced crack control. The results show that the proposed approach can be used to design the properties of UHPFRC jackets in order to achieve a desired structural response in terms of strength, ductility, and crack control.

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Section: Tension In Fibers Across the Critical Crackmentioning

confidence: 99%

Section: Crack Controlmentioning

confidence: 99%

“…The SDEM focuses on a pure opening of the crack (Mode I) and links the stress across the crack to the crack width w according to: