Investigation of prestressed concrete box beams of an elevated expressway

The object of this paper is to share the experience gained from an investigation of prestressed concrete box beams of the elevated roadway of the F. G. Gardiner Expressway in Toronto, 16 years after construction. The 18–30 m long, simply supported beams, which are either pretensioned or posttensioned with prestressing strands, are covered by concrete topping and asphalt. Methods of investigation include coring, chloride-content tests, and power chipping of soffit areas. Rusted reinforcing steel, rusted prestressing strands, and delaminated or spalled concrete were found at transverse joints and at beam soffits. Concrete damage due to bird droppings, as well as a beam with nearly 60% strand loss, were discovered. Causes for deterioration are discussed and proposed repair methods are described.

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Flexural Response of CFRP Prestressed Concrete Box Beams for Highway Bridges

PCI Journal ◽

10.15554/pcij.01012004.92.104 ◽

2004 ◽

Vol 49 (1) ◽

pp. 92-104 ◽

Cited By ~ 3

Author(s):

Nabil F. Grace ◽

S. B. Singh ◽

Mina M. Shinouda ◽

Sunup S. Mathew

Keyword(s):

Prestressed Concrete ◽

Highway Bridges ◽

Flexural Response ◽

Box Beams

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Error Estimation of Linear Polarization Resistance Measurement Caused by IR Drop for Reinforcement Corrosion in Concrete

Materials Science Forum ◽

10.4028/www.scientific.net/msf.866.14 ◽

2016 ◽

Vol 866 ◽

pp. 14-19

Author(s):

Jin Xia Xu ◽

Ya Long Cao ◽

Lin Hua Jiang ◽

Ying Bin Song ◽

Wei Feng

Keyword(s):

Linear Polarization ◽

Polarization Resistance ◽

Chloride Content ◽

Chloride Ions ◽

Resistance Measurement ◽

Reinforcing Steel ◽

Error Level ◽

Corrosion Condition ◽

Linear Polarization Resistance ◽

Ir Drop

In order to evaluate more accurately the corrosion condition of reinforcing steel in chloride contaminated concrete, it is significant to investigate the error level in the linear polarization resistance measurement caused by IR drop. Concretes with eight levels of chloride ions (ranging from 0% to 2.0% by mass of cement) by adding different amounts of sodium chloride in the mixing water were prepared. Linear polarization measurements with and without IR compensation, were applied to determine the error level. Besides, half-cell potential method was employed to detect the corrosion condition of reinforcing steel. The results indicate that the error level is so low (less than 5.0%) that the IR drop can be negligible when the chloride content is relatively lower (0.6% or less by mass of cement). However, the error level is increased with the increase of chloride content. The IR drop is suggested to be compensated when the chloride content is relatively higher (more than 0.6% by mass of cement). At this time, the onset of active corrosion of reinforcing steel is also found.

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Performance assessment on degrading concrete structures including considerations on the time variant alteration

10.2749/ghent.2021.0341 ◽

2021 ◽

Author(s):

Fritz Binder ◽

Stefan L. Burtscher ◽

Alfred Strauss

Keyword(s):

Prestressed Concrete ◽

Chloride Content ◽

Degradation Process ◽

Analytic Hierarchy ◽

Reliable Determination ◽

Chloride Attack ◽

Durability Assessment ◽

Condition Indices ◽

Condition State ◽

Hierarchy Process

<p>The infrastructure of ASFiNAG is mainly built from reinforced and prestressed concrete, which despite all regular maintenance measures, is subject to ageing and degradation. The major degradation process is chloride attack, followed by carbonation, which both lead to corrosion of the reinforcing steel. In this paper chlorides in the concrete are analysed with a new method, which represents a major improvement over previous assessment. The paper also introduces a new concept for the durability assessment by using objective indicators, like chloride content, electrical resistivity, and corrosion potential. For objectivity and a reliable determination of the condition state, an overall performance index derived from the condition indices using an analytic hierarchy process (AHP) is adopted. The model is applied to excellent and dense data from a monitoring system and investigations taken from reinforced concrete components beside the motorway.</p>

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Optimal Localization of Smart Aggregate Sensor for Concrete Damage Monitoring in PSC Anchorage Zone

Sensors ◽

10.3390/s21196337 ◽

2021 ◽

Vol 21 (19) ◽

pp. 6337

Author(s):

Quang-Quang Pham ◽

Ngoc-Loi Dang ◽

Quoc-Bao Ta ◽

Jeong-Tae Kim

Keyword(s):

Damage Detection ◽

Prestressed Concrete ◽

Impedance Model ◽

Artificial Damage ◽

Smart Aggregate ◽

Damage Monitoring ◽

Concrete Damage ◽

Potential Damage ◽

Optimal Localization ◽

Real Scale

This study investigates the feasibility of smart aggregate (SA) sensors and their optimal locations for impedance-based damage monitoring in prestressed concrete (PSC) anchorage zones. Firstly, numerical stress analyses are performed on the PSC anchorage zone to determine the location of potential damage that is induced by prestressing forces. Secondly, a simplified impedance model is briefly described for the SA sensor in the anchorage. Thirdly, numerical impedance analyses are performed to explore the sensitivities of a few SA sensors in the anchorage zone under the variation of prestressing forces and under the occurrence of artificial damage events. Finally, a real-scale PSC anchorage zone is experimentally examined to evaluate the optimal localization of the SA sensor for concrete damage detection. Impedance responses measured under a series of prestressing forces are statistically quantified to estimate the performance of damage monitoring via the SA sensor in the PSC anchorage.

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Flexural Behavior of a 30-Meter Full-Scale Simply Supported Prestressed Concrete Box Girder

Applied Sciences ◽

10.3390/app10093076 ◽

2020 ◽

Vol 10 (9) ◽

pp. 3076 ◽

Cited By ~ 3

Author(s):

Jianqun Wang ◽

Shenghua Tang ◽

Hui Zheng ◽

Cong Zhou ◽

Mingqiao Zhu

Keyword(s):

Prestressed Concrete ◽

Mechanical Performance ◽

Compressive Strain ◽

Full Scale ◽

Flexural Behavior ◽

Destructive Testing ◽

Scaled Model ◽

Box Girder ◽

Simply Supported ◽

Prestressing Tendon

Compared with scaled-model testing, full-scale destructive testing is more reliable since the test has no size effect and can truly record the mechanical performance of the structure. However, due to the high cost, only very few full-scale destructive tests have been conducted on the flexural behavior of prestressed concrete (PC) box girders with girders removed from decommissioned bridges. Moreover, related destructive testing on the flexural behavior of a new precast box girder has been rarely reported. To investigate the flexural behavior and optimize the design, destructive testing of a 30-meter full-scale simply supported prestressed box girder was conducted at the construction site. It is illustrated that the failure mode of the tested girder was fracture of the prestressing tendon, and the corresponding maximum compressive strain in the top flange was only 1456 μ ε , which is far less than the ultimate compressive strain (3300 μ ε ). Therefore, the concrete in the top flange was not fully utilized. A nonlinear analysis procedure was performed using the finite strip method (FSM). The validity of the analysis was demonstrated by comparing the analytical results with those of the full-scale test in the field and a scaled model test in a laboratory. Using the developed numerical method, parametric analyses of the ratio of reinforcement were carried out. The prestressing tendon of the tested girder was increased from four strands to six strands in each duct. After the optimization of the prestressed reinforcement, the girder was ductile and the bearing capacity could be increased by 44.3%.

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THE EFFECT OF SHEAR REINFORCEMENT RATIO ON PRESTRESSED CONCRETE BEAMS SUBJECTED TO IMPACT LOAD

Proceedings of International Structural Engineering and Construction ◽

10.14455/isec.res.2018.55 ◽

2018 ◽

Vol 5 (1) ◽

Cited By ~ 1

Author(s):

Mohamad Elani ◽

Yehya Temsah ◽

Hassan Ghanem ◽

Ali Jahami ◽

Youmn Al Rawi

Keyword(s):

Finite Element ◽

Prestressed Concrete ◽

Impact Load ◽

Nonlinear Behavior ◽

Element Model ◽

Shear Reinforcement ◽

Dynamic Increase Factor ◽

Concrete Damage ◽

Different Response ◽

The Impact

Structural elements subjected to impact loads have a different response than those subjected to static loads. This research studied the effect of using shear reinforcement to reduce the local damage occurred when an impact load applied on a prestressed concrete beam. An accurate finite element model was provided for the analysis using the advanced volumetric finite element modeling program (ABAQUS). The concrete material was defined using the built in concrete damage plasticity model (CDP), that considers the nonlinear behavior of concrete when subjected to dynamic loading. All material properties were modified using the dynamic increase factor (DIF) to consider the effect of impact loading. It was realized that the failure was concentrated in the impact zone. However, using shear reinforcement reduced the permanent damage occurred due to impact.

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