Redevelopment of Prestressing Force in Severed Prestressed Strands

Kasan, Jarret; Harries, Kent A.

doi:10.1061/(asce)be.1943-5592.0000177

Cited by 6 publications

(5 citation statements)

References 2 publications

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“…2. The transfer length a the sides of the corroded zones where the strand breaks occurred (see the previous section) was calculated by the transfer length of 60 diameters proposed by Kasan and Harries 14 for strands severed in damaged concrete.…”

Section: Prestressing Force Along the Length Of The Beammentioning

confidence: 99%

“…The model takes into account two different situations: (1) the cut of the post‐tensioning tendon at the beam ends (without signs of corrosion) (2) and the corrosion of the pretensioned strands. For the effect of a cut of the tendon in a post‐tensioned beam the analytical approach reported by Cavell and Waldron 13 is used, considering the friction between strand and grout and the wedging action of the tendon due to Poisson's effect. Given the initial stress at tensioning f r , the steel stress f r at a distance x from the cut is:

f_{r} = f_{s} (1 - \exp (\frac{- 4 μ ν_{c} x}{d_{s} ((), 1 ((), 1 goodbreak+ ν_{s}) \frac{E_{s}}{E_{c}})})) .

The strand diameter is d s ; the friction coefficient μ is estimated with a constant value of 0.2; the Poisson coefficients of concrete and steel are ν c = 0.2 and ν s = 0.3.Note that the bond was not affected by corrosion at the ends where the cuts were made: no signs of corrosion and cracking were visible. The transfer length a the sides of the corroded zones where the strand breaks occurred (see the previous section) was calculated by the transfer length of 60 diameters proposed by Kasan and Harries 14 for strands severed in damaged concrete. …”

Section: Modelmentioning

confidence: 99%

“…The bottom row strands were designed debonded over a 12 ft (3.6 m) length; the two strands above were debonded along 10 ft (3.0 m). The corresponding prestress distribution is considered; the transfer length was calculated equal to 40 diameters, based on the test results by Kasan and Harries 14 on strands in real bridge beams with reinforcement and concrete similar to those in the tests considered here.…”

Section: Modelmentioning

confidence: 99%

See 2 more Smart Citations

Structural assessment of prestressed beams with natural corrosion

Coronelli

Mircea

Rogers³

et al. 2022

Structural Concrete

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An experimental campaign carried out on prestressed bridge beams corroded in a marine environment is analyzed in order to understand the failure modes related to the deterioration phenomena and setup models for capacity assessment. Three main failures modes were identified: shear in the web, shear failure in corroded zones with prestress loss and flexural failure for corroded strands in tension; this last mode becomes dominant for increasing corrosion. A truss model was used for flexure and shear resistance, considering the presence of both bottom pretensioned strands breaks and a draped post‐tensioned tendon cuts. The development of new anchorage at the sides of the damaged zones of the strands was modeled. Corrosion effects are modeled reducing the reinforcement cross‐section and bond, and modifying the prestressing distribution and the truss angle for shear. The accuracy of the model predictions relies on the corroded cross section loss input. In the light of the comparison of test and models results a methodology setup in the literature is here extended with scenarios considering higher levels of corrosion damage.

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Section: Prestressing Force Along the Length Of The Beammentioning

confidence: 99%

f_{r} = f_{s} (1 - \exp (\frac{- 4 μ ν_{c} x}{d_{s} ((), 1 ((), 1 goodbreak+ ν_{s}) \frac{E_{s}}{E_{c}})})) .

Section: Modelmentioning

confidence: 99%

Section: Modelmentioning

confidence: 99%

See 1 more Smart Citation

Structural assessment of prestressed beams with natural corrosion

Coronelli

Mircea

Rogers³

et al. 2022

Structural Concrete

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show abstract

“…These failures may cause a complete loss of bond, especially when no confining reinforcement exists [24]. In these cases, the effective prestressing force may be redeveloped by bond at a distance from the damaged location [25].…”

Section: Bond Mechanisms and Modelsmentioning

confidence: 99%

Strand bond performance in prestressed concrete accounting for bond slip

Martí‐Vargas

Ros

Hale

2013

Engineering Structures

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(José R. Martí-Vargas) 10 11 Abstract: 12This paper presents the results of an experimental research program addressing the bond 13 behavior of prestressing strands in pretensioned prestressed concrete members after anchorage 14 failure has occurred. A test methodology based on measuring the prestressing strand force and 15 strand end slip at the specimens' free end was employed. Transmission-and anchorage-length 16 tests were performed on several series of prestressed specimens with different embedment 17 lengths using twelve concrete mixes. Average bond stresses along the transmission length and 18 the anchorage length were obtained for specimens with release strengths ranging from 24 19MPa to 55 MPa. For the anchorage analysis, a parameter was developed that includes strand 20 slip to be used in determining anchorage length. Based on the test results, an analysis to 21 experimentally substantiate the Stress Waves Theory of Janney has been proposed. 22Additionally, the potential bond performance of prestressing strands after anchorage failure at 23 the end regions has been suggested. 24

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“…This may result in complete bond loss, especially if 51 there is no confining reinforcement (den Uijl 1995). In these cases, it is possible to 52 redevelop effective prestressing force by bond at a distance from the damaged location 53 (Kasan and Harries 2011). 54 b) A long transfer length reduces the available member length to resist bending moment and 55 shear, and therefore increases member cost.…”

Section: Length (Cen 2004 -Cen: Committee European Of Normalization-)mentioning

confidence: 99%

Predicting Strand Transfer Length in Pretensioned Concrete: Eurocode versus North American Practice

Martí‐Vargas

Hale

2013

J. Bridge Eng.

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4Prestressing strands are commonly used in pretensioned prestressed concrete bridges 5 construction. Transfer length is an important parameter for structural design. This paper 6 presents a comparative study on strand transfer length provisions from Eurocode-2 and North 7American practice, and identifies similarities and differences between both models. A 8 database of measured transfer lengths according to several authors has been compiled and 9 compared with predictions according to code provisions. The intervals of predictions are 10 smaller than those corresponding to the experimental results, and they are smaller when code 11 provisions are more simplified: the interval from Eurocode-2 is greater than that from ACI-12 318 which, in turn, is greater than the interval from AASHTO. The number of underestimated 13 cases is lower for Eurocode-2 because of the higher predicted values, but situations in which a 14 short transfer length is unfavorable are neglected by all models because they are not good 15 predictions of shorter measured transfer lengths. When a transfer length estimation criterion is 16 based on an allowable free end slip, more cases are excluded from the ACI-318 provisions. 17

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Redevelopment of Prestressing Force in Severed Prestressed Strands

Cited by 6 publications

References 2 publications

Structural assessment of prestressed beams with natural corrosion

Structural assessment of prestressed beams with natural corrosion

Strand bond performance in prestressed concrete accounting for bond slip

Predicting Strand Transfer Length in Pretensioned Concrete: Eurocode versus North American Practice

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