Genetic Analysis and Repair of Cracks in Prestressed Concrete Box Girders during Precast Period

2011 ◽  
Vol 366 ◽  
pp. 55-58
Author(s):  
Shi Ming Liu ◽  
Shun Bo Zhao
Keyword(s):  
Genetic Analysis ◽  
Prestressed Concrete ◽  
Initial Period ◽  
Environmental Condition ◽  
Box Girders ◽  
Construction Procedure ◽  
Precast Prestressed Concrete ◽  
Space Width ◽  
Construction Works

During the initial period of precast prestressed concrete box girders in a bridge, some cracks appeared in five box girders. The paper describes the crack states including location, elongation, space, width and depth. The geneses of the cracks are analyzed considering the concrete proportion, environmental condition and construction procedure. Four of them were permitted to be used after mending of these cracks and another one was abandoned directly. After the preventing measurement was adopted, no cracks appeared in the follow-up precast box girders. The experience can be as reference for the similar construction works.

scholarly journals Influence of end Contsrains on the Global Behaviour of a Box Girder

2016 ◽  
Vol 6 (1) ◽  
pp. 7-15
Author(s):  
Daniela Mihaela Boca ◽  
A. Faur ◽  
A. Boca
Keyword(s):  
Prestressed Concrete ◽  
Transport Infrastructure ◽  
Box Girders ◽  
3D Fem ◽  
Important Data ◽  
Box Girder ◽  
Fem Model ◽  
Global Behaviour ◽  
Applied Forces ◽  
Precast Prestressed Concrete

Abstract This study aims to presents the importance of end constrains, boundary conditions and position of the applied forces regarding the design of precast/prestressed concrete box girders. The study is based on a destructive test which was performed on a 37.1 m span single-cell prestressed concrete box girder. The scope of the test was to certify the usage of such girders for the new Transylvania motorway bridges. The test is numerically reproduced through a full 3D FEM model implemented in SAP2000. The influence of the end diaphragms is considered by analysing the beam’s behaviour to six loading conditions: one of which is replicating the loadings during the test, while the others are conceived as real vertical and horizontally loading scenarios. The results obtained for the girders with and without end constrains are compared. The performances of both design solutions in the presence of prestressing are highlighted where applicable. It is considered that the results of this study may provide very important data if considering that Romania has an urgent need to realize a modern and an adequate transport infrastructure.

scholarly journals Structural Health Monitoring of Precast Concrete Box Girders Using Selected Vibration-Based Damage Detection Methods

2010 ◽  
Vol 2010 ◽  
pp. 1-21 ◽  
Author(s):  
Zhengjie Zhou ◽  
Leon D. Wegner ◽  
Bruce F. Sparling
Keyword(s):  
Damage Detection ◽  
Prestressed Concrete ◽  
Precast Concrete ◽  
Detection Methods ◽  
Box Girders ◽  
Localization Accuracy ◽  
Structural Health ◽  
Proportional Increase ◽  
Low Levels ◽  
Precast Prestressed Concrete

Precast, prestressed concrete box girders are commonly used as superstructure components for short and medium span bridges. Their configuration and typical side-by-side placement make large portions of these elements inaccessible for visual inspection or the application of nondestructive testing techniques. This paper demonstrates that vibration-based damage detection (VBDD) is an effective alternative for monitoring their structural health. A box girder removed from a dismantled bridge was used to evaluate the ability of five different VBDD algorithms to detect and localize low levels of spalling damage, with a focus on using a small number of sensors and only the fundamental mode of vibration. All methods were capable of detecting and localizing damage to a region within approximately 1.6 times the longitudinal spacing between as few as six uniformly distributed accelerometers. Strain gauges configured to measure curvature were also effective, but tended to be susceptible to large errors in near support damage cases. Finite element analyses demonstrated that increasing the number of sensor locations leads to a proportional increase in localization accuracy, while the use of additional modes provides little advantage and can sometimes lead to a deterioration in the performance of the VBDD techniques.

Real condition experiment on a new bridge weigh-in-motion solution for the traffic assessment on road bridges

2021 ◽  
Author(s):  
François-Baptiste Cartiaux ◽  
Véronique Le Corvec ◽  
Jorge Semiao ◽  
Bernard Jacob ◽  
Franziska Schmidt ◽  
...  
Keyword(s):  
Prestressed Concrete ◽  
Large Scale ◽  
Bridge Deck ◽  
Bridge Management ◽  
Box Girders ◽  
Long Span ◽  
Traffic Loads ◽  
Weigh In Motion ◽  
Bridge Weigh In Motion ◽  
Precast Prestressed Concrete

<p>Weigh-in-Motion is currently the only way to precisely assess and monitor traffic loads on road bridges from real measurements. This assessment helps to detect potential overweight vehicles and to optimize the maintenance operations on the bridge thanks to an accurate knowledge of its real load conditions.</p><p>An experiment, performed on a precast prestressed concrete beam girders bridge overcrossing a highway in France, is described. The Weigh-in-Motion (WIM) system uses the bridge deck as a large scale, part of the weighing device, and measures strain in critical parts of the structure.</p><p>The system is able to get significantly accurate estimations of the gross weight of the vehicles on most types of bridges, including long span box girders, large composite decks or the multiple precast prestressed concrete beams considered in the study. However, the axle load estimation is still much less accurate and not presented here.</p><p>The experiment started in February 2019 and is still going on, also proving the robustness of the solution for an operation over long durations, as a permanent part of the bridge management through its whole lifecycle. Thus, the WIM sensors used are relevant for the Structural Health Monitoring of the bridge deck as well.</p>

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