Experimental Evaluation of Properties of 120 Years Old Concretes at Two Concrete Bridges in Slovakia

Paulík, Peter; Bačuvčík, Michal; Ševčík, Patrik; Janotka, Ivan; Gajdošová, Katarína

doi:10.4028/www.scientific.net/ssp.249.227

Cited by 7 publications

(3 citation statements)

References 2 publications

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“…In cases where the material properties are not available, it is almost impossible to determine the actual state of prestressing [ 22 , 23 ]. Hence, the determination of material properties was part of the experimental program, as this was a necessary basis for numerical analysis and evaluation of residual prestressing.…”

Section: Experimental Programmentioning

confidence: 99%

Indirect Determination of Residual Prestressing Force in Post-Tensioned Concrete Beam

et al. 2021

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A diagnostic survey on the precast prestressed bridge Nižná confirmed significant deterioration due to environmental distress. Evidently, decisive failures of the structure have a similar character as in the previous precast prestressed bridge in Podbiel in the northern part of Slovakia. These failures result from the unsuitable concept of the first generation of precast prestressed concrete beams, which was used in the former Czechoslovakia in the second half of the 20th century. Subsequently, experimental verification using the proof-load test was also executed. This bridge was built in 1956, so at the time of testing, it was 60 years old. The paper presents the indirect determination of prestressing level in one precast post-tensioned concrete beam using the saw-cut method. Experimental measurement was executed during the bridge demolition. Subsequently, a 2D numerical model in ATENA 2D Software, with the assumption of nonlinear material behavior for verification of experimental results, was performed. Finally, the residual prestressing force was evaluated and compared with the expected state of prestressing according to Eurocodes after 60 years of service.

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Section: Experimental Programmentioning

confidence: 99%

Indirect Determination of Residual Prestressing Force in Post-Tensioned Concrete Beam

et al. 2021

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“…This general knowledge includes many material properties, such as information about the real geometry of structural members and reinforcement, damage and deterioration (obtained from visual inspections); data containing the effect of significant overloading of the structure, etc. [ 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

Determination of Prestress Losses in Existing Pre-Tensioned Structures Using Bayesian Approach

Moravčík

Kraľovanec

2022

Materials

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Deterioration of materials and structures is an unavoidable fact, and prestressed concrete structures are not an exception. The evaluation of load-carrying capacity and remaining service life includes collecting various information. However, one type of information is essential and the most important, the state of prestressing, which inevitably decreases over time. Currently, many possible methods for the evaluation of prestressing are available. These techniques are part of the structural assessment and provide residual prestressing force value which is later used in the evaluation process. Therefore, it is suitable to provide the value of prestressing force based on certain probabilistic backgrounds. This study addresses the determination of residual prestressing force in pre-tensioned railway sleepers one year after their production, using the so-called Bayesian approach. This technique is focused on the validation of results obtained from the application of the non-destructive indirect saw-cut method. The Bayesian approach considers analytic calculation as the primary method of prestressing determination. In this paper, Monte Carlo simulation was used to determine the total variability that defines all Bayesian systems of probability functions. Specifically, a total of 1000 simulations was applied, and the current random vector of prestressing force derived from the analytical calculation has been assumed as a normally distributed function. Finally, obtained results for different depths of saw-cuts are compared. The results of the experimental and statistical determination of residual prestressing force provide its value with a 95% confidence level. This study suggests that the implementation of the probability approach can be an effective tool for determining prestress losses.

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“…Consequently, we are forced to deal with it from the moment of design and construction of structural members. One particular form of deterioration-corrosion of prestressing steel-affects the load-carrying capacity and remaining service lifetime of structures [1][2][3][4][5][6]. This kind of deterioration is difficult to detect through the regular inspection and belongs among the most critical types of damage in prestressing tendons (wires, strands, or cables) [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Effect of Water Condensate on Corrosion of Wires in Ungrouted Ducts

et al. 2021

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In the case of existing prestressed concrete structures, information about the actual state of prestressing is an important basis for determining their load-carrying capacity, as well as remaining service lifetime. This is even more important in the case of existing prestressed concrete bridges, which are exposed to a more aggressive environment than the other prestressed concrete structures. The level of prestressing is affected and reduced by prestress losses at a given time. In calculating the internal forces and stresses, required for the assessment of the Ultimate Limit State and the Serviceability Limit State, it is necessary to know not only the prestressing level but also the cross-sectional area of the prestressing steel (wire, strand or cable), which can change in time due to corrosion. In practice, in the case of the pre-tensioned concrete members, it has often happened in the past that cable ducts have been grouted only partially, or not at all, due to poor grouting technology. Experts did not realize what this could cause in the future—the penetration of water with aggressive agents directly into the cable duct and consequently corrosion of the prestressing steel, which means not increased protection of the steel, but rather acceleration of degradation. On the other hand, in many cases, corrosion also occurs in ducts that are not grouted and no water has entered them. This paper deals with this phenomenon—the formation of corrosion of prestressing steel in cable ducts in ungrouted ducts due to moisture. This problem was investigated experimentally and numerically in the simulation program ESP-r. Experimental measurements and numerical simulations have shown that the water vapor condenses in the cable ducts, which can subsequently cause corrosion of the prestressing steel.

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Experimental Evaluation of Properties of 120 Years Old Concretes at Two Concrete Bridges in Slovakia

Cited by 7 publications

References 2 publications

Indirect Determination of Residual Prestressing Force in Post-Tensioned Concrete Beam

Indirect Determination of Residual Prestressing Force in Post-Tensioned Concrete Beam

Determination of Prestress Losses in Existing Pre-Tensioned Structures Using Bayesian Approach

Effect of Water Condensate on Corrosion of Wires in Ungrouted Ducts

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