Tendon Stress in Continuous Unbonded Prestressed Concrete Members Part 2: Parametric Study

Allouche, Erez N.; Campbell, T. I.; Green, M F; Soudki, Khaled

doi:10.15554/pcij.01011999.60.73

Cited by 31 publications

(14 citation statements)

References 5 publications

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“…For prestressed concrete beams, the beam element models have been popular for their merits of computational efficiency and accuracy. Allouche et al [11] described a numerical model which used the finite beam element method incorporating an iterative moment-curvature approach to compute the stress in unbonded tendons. The model can take care of continuous rectangular beams subjected to one-point, uniform or third-point loading, but it neglected the nonlinear geometric effects of the structure which may play an important role in the behaviour of slender beams such the ones used for unbonded post-tensioned beams.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear and time-dependent analysis of continuous unbonded prestressed concrete beams

Lou

Lopes

2013

Computers & Structures

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This paper describes a numerical model developed to predict the full-range nonlinear response, as well as time-dependent service-load behaviour, of continuous beams prestressed with internal unbonded tendons. Both geometric and material nonlinearities are considered. The strain increment in unbonded tendon, at any deformed state, is computed from the elongation of the entire tendon between end anchorages. The unbonded prestressing contributes to the concrete beam by equivalent loads, which would be updated continuously during the solution process. The analysis reproduces the experimental results of continuous beam specimens with favourable agreement. Some important aspects of behaviour of the continuous beams are examined.

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Section: Introductionmentioning

confidence: 99%

Nonlinear and time-dependent analysis of continuous unbonded prestressed concrete beams

Lou

Lopes

2013

Computers & Structures

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“…Since then, research work on the topic proliferated. A comprehensive evaluation of the stateof-the-art up to 1991 was carried out by Naaman and Alkhairi, 13 while Allouche et al 19 reported another comprehensive literature review of the topic up to 1998. A common approach in the prediction of the ultimate tendon stress f ps at flexural failure of a beam with unbonded tendons is to start with the effective prestress f pe and to determine the subsequent stress increment˜f ps due to any additional load leading to ultimate failure.…”

Section: Existing Literaturementioning

confidence: 99%

“…Eliminating the neutral axis depth at ultimate c between equation (19) and the force equilibrium equation of equation (8a) at the critical section, a general equation of j can be obtained as…”

Section: Design Approach Based On Neutral Axis Depthmentioning

confidence: 99%

Prediction of ultimate stress in unbonded prestressed tendons

Au¹,

Du²

2004

Magazine of Concrete Research

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The behaviour of prestressed concrete members with unbonded tendons is different from that of members with bonded tendons. While the behaviour of prestressed concrete beams with bonded tendons is characterised by that existing at individual sections, analysis of the entire member is necessary for beams with unbonded tendons. This paper examines various design methods for the determination of ultimate tendon stress at flexural failure of prestressed concrete beams with unbonded tendons. Two broad categories of deformation-based approaches have been identified, namely those based on the span-depth ratio together with loading type, and those based on the neutral axis depth. These methods are reviewed critically. A new design formula has been proposed in the light of the available experimental data. It is applicable not only to the conventional high-strength steel prestressing tendons, but also to those made of other materials such as fibre-reinforced polymer.

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“…Even though these differences may not be critical at the service load stage, they can have a considerable effect at the ultimate load stage. Accordingly, most experimental studies (Allouche et al, 1999;Aparicio et al, 2002;Cairns and Rafeeqi, 2002;Rao, 1996;Tan and Ng, 1997;Virlogeux, 1990) have concentrated on beam structures with different cable profiles in the investigation of the structural behaviour of the externally prestressed flexural member and the effects of the external cable.…”

mentioning

confidence: 99%

Inelastic behaviour of PSC beams with unbonded external tendons

Kwak¹,

Son²

2010

Magazine of Concrete Research

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In this paper, an analytical method that can describe the structural behaviour of prestressed concrete (PSC) bridges with unbonded external tendons is developed. Since the unbonded external tendon is directly connected to the deviators while maintaining a straight configuration, it has a different deformation field from that of concrete and accompanies a secondary effect caused by the change of the primary eccentricity between the concrete and external tendon. The friction slip at the deviators is also taken into consideration on the basis of the force equilibrium between the friction force and the driving force. Moreover, all the material non-linearities and time-dependent deformations such as creep and shrinkage of concrete and relaxation of the tendon are included because the centroidal axis of a section changes according to cracking and time-dependent effects in the constituent materials. Through correlation studies between experimental data and analytical results, it is verified that the proposed numerical model can effectively predict the structural behaviour of PSC bridges with comparative precision.

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Tendon Stress in Continuous Unbonded Prestressed Concrete Members Part 2: Parametric Study

Cited by 31 publications

References 5 publications

Nonlinear and time-dependent analysis of continuous unbonded prestressed concrete beams

Nonlinear and time-dependent analysis of continuous unbonded prestressed concrete beams

Prediction of ultimate stress in unbonded prestressed tendons

Inelastic behaviour of PSC beams with unbonded external tendons

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