scholarly journals DAMAGE TO CONCRETE BRIDGES DUE TO REINFORCEMENT CORROSION

Transport ◽  
2002 ◽  
Vol 17 (4) ◽  
pp. 137-142 ◽  
Author(s):  
Zenonas Kamaitis
Keyword(s):  
Prestressed Concrete ◽  
Poor Quality ◽  
Concrete Cover ◽  
Concrete Bridges ◽  
Prestressing Steel ◽  
Existing Structures ◽  
Concrete Carbonation ◽  
Prestressed Reinforcement ◽  
Segmental Bridge

Corrosion of reinforcement initiated by concrete carbonation and chloride contamination is the most common type of deterioration of concrete bridges. Based on the author's experience a number of cases is reported in which the corrosion of ordinary and prestressed reinforcement as well as the causes and consequences of deterioration observed are presented. Investigations have shown that the main reasons are: insufficient concrete cover, poor quality of concrete, and ingress of aggressive salts. The carbonation depth must be related to the histogram ofrebar cover depths and the probability of their coincidence can be predicted. The monitoring of tendon conditions in prestressed concrete precast post-tensioned segmental bridge decks shows that the voids and the water are often present in the ducts leading to the local rusting of tendons. The wires used in tendons are liable to fail in tension that was observed in some prestressed concrete bridges. Unfortunately, no reliable procedures of determining the condition of prestressing steel in existing structures are available.

Prestressing Steel Ropes - Corrosion Impact on its Properties

2020 ◽  
Vol 309 ◽  
pp. 272-280
Author(s):  
Jiří Kolísko ◽  
Vítězslav Vacek ◽  
Petr Pokorný ◽  
Michaela Kostelecká
Keyword(s):  
Maraging Steel ◽  
Prestressed Concrete ◽  
Mechanical Characteristics ◽  
Concrete Structures ◽  
Steel Reinforcement ◽  
Prestressing Steel ◽  
Anticorrosion Protection ◽  
Long Time ◽  
Prestressed Reinforcement ◽  
Prestressed Structures

Steel reinforcement made of refined maraging steel in the form of wires and tendons has been for a long time used commonly for reinforcement of prestressed concrete structures. Defects on some of them and unfortunately even accidents of some cases of bridge objects, mainly recently published by media, related to corrosion of prestressed reinforcement awoke interest of both professional and wide non-professional public related to its durability. This issue also opens up a question of durability and liability of prestressed structures. In majority of existing prestressed structures the anticorrosion protection of reinforcement was traditionally secured mainly by alkalinity of the environment, i.e. concreting and/or grouting of prestressed elements in ducts. The abstract presents information related mainly to mechanical characteristics of corrosion-affected prestressed elements.

Assessment of Load-Bearing Capacity of Bridges

2017 ◽  
Vol 259 ◽  
pp. 113-118 ◽  
Author(s):  
Jaroslav Navrátil ◽  
Michal Drahorád ◽  
Petr Ševčík
Keyword(s):  
Bearing Capacity ◽  
Prestressed Concrete ◽  
Iterative Solution ◽  
Concrete Bridges ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Prestressed Concrete Bridges ◽  
Existing Structures ◽  
Non Linear

The paper aims to the determination of load-bearing capacity of reinforced/prestressed concrete bridges subjected to the combination of all components of internal forces according to Eurocode standards for assessment of existing structures. Undoubtedly bridge load rating is laborious hand-iterative process, especially when it comes to reinforced and/or prestressed concrete bridges. The engineer can spend days and weeks trials and errors in the estimation of bridge load-carrying capacity. The problem lies in the determination of load-bearing capacity of cross-section subjected to the combination of normal and shear forces, bending and torsional moments. Due to the different effects of permanent and variable loads and the non-linear behavior of structural materials, the problem becomes non-linear and its solution requires the use of suitable iterative method. Optimized iterative solution was implemented into IDEA StatiCa software and the results are presented in this paper.

scholarly journals Assessment of Mechanical Properties of Corroded Prestressing Strands

2020 ◽  
Vol 10 (12) ◽  
pp. 4055 ◽  
Author(s):  
Chi-Ho Jeon ◽  
Cuong Duy Nguyen ◽  
Chang-Su Shim
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Prestressed Concrete ◽  
Critical Issue ◽  
Concrete Bridges ◽  
Structural Behavior ◽  
Maximum Deformation ◽  
Prestressing Steel ◽  
External Tendons ◽  
Governing Factor

The corrosion of prestressing steel in prestressed concrete bridges is a critical issue for bridge maintenance. To assess structures with corroded strands, it is necessary to define the mechanical properties of the strands and their influence on the structural behavior. In this study, corroded strands were taken from external tendons in existing post-tensioned concrete bridges and tested to determine the effects of corrosion on their tensile properties. Empirical equations for the tensile strength and ductility of the corroded strands were proposed using test results. The most corroded wire governs the mechanical properties of the strand. Experiments on prestressed concrete beams with a single corroded strand were conducted to investigate their structural behavior. A reduction in the flexural strength and maximum deformation was observed in these experiments. According to the section loss of a wire in a strand and its location in a beam, the flexural capacity can be evaluated using the proposed equation. The reduced ultimate strain of the corroded strand can be the governing factor of the flexural strength.

Strengthening of the Frame Structure at the Timisoreana Brewery, Romania

2010 ◽  
pp. 57-80
Author(s):  
Corneliu Bob ◽  
Sorin Dan ◽  
Catalin Badea ◽  
Aurelian Gruin ◽  
Liana Iures
Keyword(s):  
Reinforced Concrete ◽  
Load Resistance ◽  
Concrete Cover ◽  
Frame Structure ◽  
Reinforced Concrete Structure ◽  
Existing Structures ◽  
Concrete Carbonation ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Lateral Load Resistance

<p>Many structures built in Romania before 1970 were designed for gravity loads with inadequate lateral load resistance because earlier codes specified lower levels of seismic loads. Some of these structures are still in service beyond their design life. Also, some deterioration was observed in existing structures due to the actions of different hazard factors. This paper presents the case study of a brewery with reinforced concrete framed structure of five storeys and a tower of nine storeys, which has been assessed and strengthened. The brewery and the tower were built in 1961 and an extension in 1971. An assessment performed in 1999 showed up local damages at slabs, main girders, secondary beams, and columns; concrete carbonation; concrete cover spalled over a large surface; complete corrosion of many stirrups and deep corrosion of main reinforcement; and some broken reinforcement. Such damage was caused by salt solution, CO2, relative humidity RH 80%, and temperatures over 40◦C. Also, inadequate longitudinal reinforcement was deduced≈ from the structural analysis. The initial design, done in 1960, was according to the Romanian codes of that time with provisions at low seismic actions. The structural system weakness is due to present-day high seismic actions. The rehabilitation of the reinforced concrete structure was performed by jacketing with reinforced concrete for the main and secondary beams and columns. In 2003, due to continuous operation and subsequent damage of the structure, a new assessment was required. It was found that some beams and one column were characterized by inadequate main and shear reinforcement as well as corrosion of many stirrups at beams. The strengthening solution adopted was based on carbon fibre reinforced polymer composites for beams and column.</p>

Fatigue reliability of deteriorating prestressed concrete bridges due to stress corrosion cracking

2001 ◽  
Vol 28 (4) ◽  
pp. 673-683 ◽  
Author(s):  
M A Maes ◽  
X Wei ◽  
W H Dilger
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Prestressed Concrete ◽  
Corrosion Cracking ◽  
Concrete Bridges ◽  
Concrete Bridge ◽  
Fatigue Reliability ◽  
Prestressing Steel ◽  
Prestressed Concrete Bridges ◽  
Prestressed Concrete Bridge

In this paper, an analysis framework is presented to develop a relationship between fatigue reliability in a prestressed concrete bridge and the progress of stress corrosion cracking (SCC) in prestressing steel. The fatigue limit state uses a cumulative damage model for prestressing steel wires, which is a function of both stress range and minimum stress. The SCC model takes into account varying degrees of material susceptibility, stress regimes, and environmental conditions and is structured around three stages: initiation of micro-cracking, propagation, and macro-crack instability using linear elastic fracture mechanics. The framework is an overall time-dependent analysis of the safety against fatigue of a prestressed concrete bridge. It involves a stochastic analysis of the evolution of prestressing wire corrosion as a function of time and a time-dependent probabilistic analysis of the fatigue reliability of the prestressed concrete bridge suffering a certain degree of deterioration. The uncertainties involved in the fatigue model, the SCC model, and traffic actions are considered. The updating of uncertainties is simplified by considering a limited number of classes representative of the severity of SCC exposure. The framework is applied to three deteriorating highway bridges.Key words: fatigue analysis, prestressing strands, stress corrosion cracking, reliability assessment, prestressed concrete bridges, deterioration.

scholarly journals Assessment of Mechanical Properties of Corroded Prestressing Strands

2020 ◽  
Author(s):  
Chi-Ho Jeon ◽  
Cuong Duy Nguyen ◽  
Chang-Su Shim
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Prestressed Concrete ◽  
Critical Issue ◽  
Concrete Bridges ◽  
Structural Behavior ◽  
Maximum Deformation ◽  
Prestressing Steel ◽  
Governing Factor ◽  
Existing Bridges

The corrosion of prestressing steel in prestressed concrete bridges is a critical issue for bridge maintenance. To assess structures with corroded strands, it is necessary to define the mechanical properties of the strands and their influence on the structural behavior. In this study, corroded strands are taken from external tendons in existing bridges and tested to define the effects of corrosion on the tensile properties of the strand. Empirical equations for the tensile strength and ductility of the corroded strand are proposed using test results. The most corroded wire governs the mechanical properties of the strand. Experiments on prestressed concrete beams with a single corroded strand are conducted to investigate the structural behavior. A reduction in the flexural strength and maximum deformation is observed from the experiment. According to the section loss of a wire in a strand and its location in a beam, the flexural capacity can be evaluated using the proposed equation. The reduced ultimate strain of the corroded strand can be the governing factor of the flexural strength.

APPLICABILITY OF WIDE-RANGE ULTRASONIC TESTING TO NON-DESTRUCTIVE INSPECTION OF GROUT CONDITION IN PRESTRESSED CONCRETE BRIDGES

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Kuniharu Fukushima ◽  
Kimihiko Amaya ◽  
Takanori Kinoshita ◽  
Isamu Yoshitake
Keyword(s):  
Prestressed Concrete ◽  
Ultrasonic Testing ◽  
Load Capacity ◽  
Comparative Investigation ◽  
Concrete Cover ◽  
Concrete Bridges ◽  
Inspection Method ◽  
Wide Range ◽  
Inspection Techniques ◽  
Non Destructive

Complete grouting of tendon ducts is important for durability of post-tensioned prestressed concrete (PC) bridges. Voids in the ducts may induce failure of PC tendons, possibly causing a reduction in load capacity and collapse of the bridge. The wide-range ultrasonic testing (WUT) is one of the non-destructive inspection techniques. The focus of this study is to examine the applicability of the WUT to grout inspection. This paper summarizes the characteristics of the non-destructive methods available for the PC grout inspection and outlines the sensing and analyzing techniques of the WUT method performed in practice in PC bridge construction. The inspection accuracy of the WUT method was examined by comparison to a sensor-based inspection method. This paper also reports comparative investigation and discusses the advantages of the WUT method including inspection accuracy, cost performance, time efficiency and safety. It was confirmed in on-site application that the WUT method was capable of determining grout condition at a concrete cover depth of 250 mm.

Load Rating a Prestressed Concrete Double T-Beam Bridge without Plans by Field Testing

2015 ◽  
Vol 2522 (1) ◽  
pp. 90-99 ◽  
Author(s):  
Carlos V. Aguilar ◽  
David V. Jáuregui ◽  
Craig M. Newtson ◽  
Brad D. Weldon ◽  
Tamara M. Cortez
Keyword(s):  
New Mexico ◽  
Prestressed Concrete ◽  
Field Testing ◽  
Concrete Bridges ◽  
Load Rating ◽  
Load Testing ◽  
Prestressing Steel ◽  
Lack Of Information ◽  
Beam Bridge ◽  
T Beam

Bridges with no design plans are an issue in New Mexico because of the many that exist throughout the state. Conventional load rating techniques cannot be used because these bridges have limited or no design documentation. This lack of information has created uncertainties regarding the load-carrying capacity of these structures. Only a few states have formal procedures on how these particular bridges should be load rated. A project was conducted for the New Mexico Department of Transportation to develop a procedure for load rating bridges without plans, including prestressed concrete bridges. In accordance with the AASHTO Manual for Bridge Evaluation, a prestressed concrete double T-beam bridge was evaluated with advanced analyses and experimental methods (including load testing and nondestructive material evaluation techniques). A four-step load rating procedure was implemented that included estimating the prestressing steel by Magnel diagrams, verifying the estimate with a rebar scanner, testing the bridge at both diagnostic and proof loads based on strain measurements, and using the proof test results to rate the bridge. Rating factors and posting loads were determined for AASHTO and New Mexico legal loads. Because of the poor condition of the shear keys (some of which were broken), it is shown that the load distribution between beams was adversely affected and the bridge should be load posted.

scholarly journals DAMAGE TO CONCRETE BRIDGES DUE TO REINFORCEMENT CORROSION

Transport ◽  
2002 ◽  
Vol 17 (5) ◽  
pp. 163-170 ◽  
Author(s):  
Zenonas Kamaitis
Keyword(s):  
Service Life ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Concrete Cover ◽  
Concrete Bridges ◽  
National Standards ◽  
Chloride Diffusion ◽  
Reinforcement Corrosion ◽  
Concrete Carbonation ◽  
Cover Cracking

The mechanisms of reinforcement corrosion in concrete are the subject of extensive research. Although reliable methods for predicting the corrosive deterioration of concrete structures do not yet exist. This paper describes the durability problem of reinforced concrete bridges based on the mechanisms of carbonation depth or chloride profile. The deterioration model considering concrete carbonation, chloride penetration and concrete cover cracking is adopted to describe the service life of concrete structures. The corrosion models include environmental conditions, concrete carbonation or chloride diffusion rates, quality of concrete cover, steel corrosion rates and many other factors that make the predicting of service life of structures extremely difficult. Finally, the author gives the details of the methods of durabilio/ verification and the proposals for its including in the national standards and practical guides.

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