In-situ methods to determine residual prestress forces in concrete bridges

Bagge, Niklas; Nilimaa, Jonny; Elfgren, Lennart

doi:10.1016/j.engstruct.2016.12.059

Cited by 57 publications

(40 citation statements)

References 7 publications

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“…Testing methods are in general required for estimating prestress losses, and include five typologies (Table 3): (1) static load testing to determine crack initiation or crack re-opening loads to obtain the available compressive stress in the bottom flange of a PC girder [23,28,54,55]. (2) Severing the prestressing tendon by cutting it into a representative exposed length after placing strain gauges on the tendon [23,56].…”

Section: Testing Methodsmentioning

confidence: 99%

“…(3) Relating the tension in the tendon to a vertical deflection recorded when known weights are suspended from it on a representative exposed length [54,57]. (4) Determining the side pressure to close the induced crack in a small cylindrical hole drilled adjacent to the tendon in the bottom flange of a PC girder [55,58]. (5) Vibration testing to determine the natural frequencies and/or dynamic responses of a PC girder [59][60][61][62][63][64][65].…”

Section: Testing Methodsmentioning

confidence: 99%

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State-of-the-Art Review on Determining Prestress Losses in Prestressed Concrete Girders

2020

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Prestressing methods were used to realize long-span bridges in the last few decades. For their predictive maintenance, devices and dynamic nondestructive procedures for identifying prestress losses were mainly developed since serviceability and safety of Prestressed Concrete (PC) girders depend on the effective state of prestressing. In fact, substantial long term prestress losses can induce excessive deflections and cracking in large span PC bridge girders. However, old unsolved problematics as well as new challenges exist since a variation in prestress force does not significantly affect the vibration responses of such PC girders. As a result, this makes uncertain the use of natural frequencies as appropriate parameters for prestress loss determinations. Thus, amongst emerging techniques, static identification based on vertical deflections has preliminary proved to be a reliable method with the goal to become a dominant approach in the near future. In fact, measured vertical deflections take accurately and instantaneously into account the changes of structural geometry of PC girders due to prestressing losses on the equilibrium conditions, in turn caused by the combined effects of tendon relaxation, concrete creep and shrinkage, and parameters of real environment as, e.g., temperature and relative humidity. Given the current state of quantitative and principled methodologies, this paper represents a state-of-the-art review of some important research works on determining prestress losses conducted worldwide. The attention is principally focused on a static nondestructive method, and a comparison with dynamic ones is elaborated. Comments and recommendations are made at proper places, while concluding remarks including future studies and field developments are mentioned at the end of the paper.

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Section: Testing Methodsmentioning

confidence: 99%

Section: Testing Methodsmentioning

confidence: 99%

State-of-the-Art Review on Determining Prestress Losses in Prestressed Concrete Girders

2020

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“…Thereafter a failure test of the strengthened girders was carried out, followed by a failure test of the bridge deck slab adjacent to the third girder still in function. The residual pre-stress forces were evaluated based on destructive and non-destructive methods, Bagge et al (2014Bagge et al ( , 2017.…”

Section: Experimental Studymentioning

confidence: 99%

Full-Scale Tests to Failure Compared to Assessments – Three Concrete Bridges

Bagge

Nilimaa

Puurula

et al. 2017

High Tech Concrete: Where Technology and Engineering Meet

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Three Swedish concrete bridges have been tested to failure and the results have been compared to assessment using standard code models and advanced numerical methods. The three tested and assessed bridges were: (1) Lautajokk, a 29 year old one span (7 m) concrete trough bridge tested in fatigue to check the concrete shear capacity. (2) Ӧrnskldsvik, a 50 year old two span trough bridge (12 + 12 m) strengthened to avoid a bending failure. (3) Kiruna Mine Bridge, a 55 year old five span prestressed concrete road bridge (18 + 21 + 23 + 24 + 20 m) tested in shear and bending of the beams and punching of the slab. The main results in the paper are the experiences of the real failure types, the robustness/weakness of the bridges, and the accuracy of different codes and models. In all three cases the bridges had a considerable hidden capacity.

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“…It has become a worldwide problem that midspan lag and box girder cracks are common in prestressed concrete (PSC) continuous box girder bridges [1,2]. The method of strengthening with a stay cable system (SCS) can fairly well solve this kind of problems, ensures the safety of the bridge structure, and extends the service life of the bridge; this method gradually gains the attention of the engineering community [3].…”

Section: Introductionmentioning

confidence: 99%

Tensioning-Phase Box Girder Deformation Prediction Model Based on Ant Colony Algorithm and Residual Correction

Liu

Wang

2018

Mathematical Problems in Engineering

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The girder of prestressed concrete continuous box girder bridge strengthened by a stay cable system has a very complex deformation mechanism, and it is difficult to establish accurate numerical model for prediction. For these problems, a prediction method based on the combination of ant colony algorithm and residual combination correction model is proposed. In this method, the measuring points are considered as the cities in TSP ant colony algorithm, the information function model and heuristic function model are constructed, the pheromone update mechanism and ant search mechanism are established, and the deformation prediction of the main girder based on ant colony algorithm prediction model is achieved. On this basis, in order to fit the random change process of main girder deflection better, the periodic function generated by harmonic transform and sine function are introduced to modify the predicted results, which makes up for the low precision defect of single model. The results show that compared with finite element method, unequal interval gray model (1,1) (UIGM (1,1)), one-time residual correction UIGM (1,1), Markov chain residual correction UIGM (1,1), and ant colony algorithm model, this model can reflect the space-time effect and casual fluctuation feature of the development of girder deformation better and also has higher prediction accuracy and efficiency. The mean relative error of the predictive value is 3.39%, the posterior error ratio is 0.060, and the accuracy level reaches level 1. This model provides a new way for the girder deformation prediction of bridge strengthened by the stay cable system.

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In-situ methods to determine residual prestress forces in concrete bridges

Cited by 57 publications

References 7 publications

State-of-the-Art Review on Determining Prestress Losses in Prestressed Concrete Girders

State-of-the-Art Review on Determining Prestress Losses in Prestressed Concrete Girders

Full-Scale Tests to Failure Compared to Assessments – Three Concrete Bridges

Tensioning-Phase Box Girder Deformation Prediction Model Based on Ant Colony Algorithm and Residual Correction

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