Deformational behavior and damage mechanism of R-UHPFRC beam subjected to fatigue loading

Sawicki, Bartłomiej; Brühwiler, E.; Bassil, Antoine

doi:10.1617/s11527-021-01745-3

Cited by 6 publications

(5 citation statements)

References 20 publications

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“…Three types of beams with T-cross section were tested: Type I with a single Ø20 mm steel rebar; Type II with a single Ø34 mm rebar and Type III with Ø20 mm Sawicki and Brühwiler Int J Concr Struct Mater (2024) 18:6 longitudinal rebar and Ø6 mm Ω shaped stirrups. Their dimensions are specified in Fig.…”

Section: Setupmentioning

confidence: 99%

Experimental and Analytical Investigation of Deflection of R-UHPFRC Beams Subjected to Loading–Unloading

Sawicki,

Brühwiler

2024

Int J Concr Struct Mater

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Under service conditions, R-UHPFRC (Reinforced Ultra High Performance Fiber Reinforced Cementitious composite) beams exhibit residual deflection after loading–unloading. This is due to the tensile strain hardening behavior of UHPFRC. The precise calculation of deflection is thus relevant and was not addressed previously. This paper proposes a material model for UHPFRC under loading–unloading and a numerical layered model for the calculation of stress and strain distribution in the cross section. Then, a curvature-based analytical model is presented for calculation of deflection of a beam. This method is finally compared and validated against experimental results as obtained from four-point bending of full-scale R-UHPFRC beams. This research reveals the need for a specific material model for UHPFRC subjected to loading–unloading for the precise calculation of the structural response of elements and members under repetitive loading, such as service or fatigue loading.

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Section: Setupmentioning

confidence: 99%

Experimental and Analytical Investigation of Deflection of R-UHPFRC Beams Subjected to Loading–Unloading

Sawicki,

Brühwiler

2024

Int J Concr Struct Mater

Self Cite

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“…Combined with the electric power calculation formula, the excitation coil's input power P in and the millivoltmeter's output power P o as the load can be calculated, respectively. The results are shown in Equations ( 8) and (9). The transmission efficiency can be obtained as shown in Equation (10).…”

Section: Theorymentioning

confidence: 99%

“…The test is carried out by pasting electronic strain gauges or embedded sensors, and then converting the stress. Sawicki [9] successfully identified the stress of rebars by using strain gauges installed on rebars and distributed optical fiber sensors for strain detection. However, this method is susceptible to temperature and has low durability.…”

Section: Introductionmentioning

confidence: 99%

Working Stress Measurement of Prestressed Rebars Using the Magnetic Resonance Method

et al. 2023

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Prestressed rebars are usually used to apply vertical prestress to concrete to prevent web cracking. The reduction of working stress will affect the durability of the structure. However, the existing working stress detection methods for prestressed rebars still need to be improved. To monitor the working stress of rebars, a magnetic resonance sensor was introduced to carry out experimental research. The correlation between rebar stress and the sensor’s induced voltage was theoretically analyzed using the magnetoelastic effect and magnetic resonance theory. A working stress monitoring method for prestressed rebars based on magnetic resonance was proposed. Working stress monitoring experiments were carried out for 16 mm, 18 mm, and 20 mm diameter rebars. The results showed that the induced voltage peak-to-peak value and the rebar prestress were nonlinearly correlated under different working conditions. Correlations between the characteristic indicators and the rebar working stress were obtained using nonlinear and linear fit. The cubic polynomial segmented fit outperformed the gradient overall linear fit, with the goodness of fit R2 greater than 0.96. The average relative error values of working stress monitoring were less than 5% under different working conditions. This provides a new method for working stress measurement of vertical prestressed rebars.

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“…This selected range corresponds to 25% of the flexural strength of the retrofitted specimen, as determined from the moment-curvature analysis. Prior research on the fatigue testing of reinforced UHPC beams has indicated rapid stiffness degradation when subjected to a loading range approximating 50% of the static strength [31,32]. Contrary to this, this study opted for a loading range equivalent to 25% of the flexural strength of the specimen, aiming to monitor stiffness degradation under repeated loading.…”

Section: Cyclic Testingmentioning

confidence: 99%

Experimental Study of Reinforced Concrete T-Beam Retrofitted with Ultra-High-Performance Concrete under Cyclic and Ultimate Flexural Loading

Khodayari,

Rehmat,

Valikhani

et al. 2023

Materials

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Structurally deficient bridges are commonly retrofitted using conventional methodologies, including reinforced concrete, steel jackets, and fiber-reinforced polymers. Although these retrofit methods aim to improve structural performance, exposure to aggressive environments may undermine the durability performance of the retrofit material. More recently, ultra-high-performance concrete (UHPC) has provided an alternative to conventional construction methods, with its superior material characteristics favoring its use in retrofit applications. In this study, a large-scale reinforced concrete (RC) T-beam is constructed and artificially damaged. The T-beam is then retrofitted with an external envelope of UHPC on all faces. Sandblasting is introduced to the surface, providing partially exposed reinforcement in the T-beam to simulate material deterioration. Additional reinforcement is placed in the web and flange, followed by casting the enveloping layer of UHPC around the specimen. The feasibility of this method is discussed, and the structural performance of the beam is assessed by subjecting the beam to cyclic and ultimate flexural loading. This paper presents the results of cyclic and ultimate testing on the RC-UHPC composite T-beam regarding load–displacement, failure mode, and strain responses. The retrofitted T-beam specimen is subjected to a cyclic loading range of 131 kN for 1.576 million cycles. Despite no visible cracks in the cyclic testing, the specimen experiences a 12.22% degradation in stiffness. During the ultimate flexural testing, the specimen shows no relative slip between the two concretes, and the typical flexural failure mode is observed. By increasing the longitudinal reinforcement ratio in the web, the failure mode can shift from localized cracking, predominantly observed in the UHPC shell, toward a more distributed cracking pattern along the length of the beam, which is similar to conventional reinforced concrete beams.

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Deformational behavior and damage mechanism of R-UHPFRC beam subjected to fatigue loading

Cited by 6 publications

References 20 publications

Experimental and Analytical Investigation of Deflection of R-UHPFRC Beams Subjected to Loading–Unloading

Experimental and Analytical Investigation of Deflection of R-UHPFRC Beams Subjected to Loading–Unloading

Working Stress Measurement of Prestressed Rebars Using the Magnetic Resonance Method

Experimental Study of Reinforced Concrete T-Beam Retrofitted with Ultra-High-Performance Concrete under Cyclic and Ultimate Flexural Loading

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