Deterioration Of Concrete Bridge Decks Research Articles

Investigation of Ground-Penetrating Radar, Impact Echo, and Infrared Thermography Methods to Detect Defects in Concrete Bridge Decks

A reinforced concrete bridge deck is often at risk of many forms of deterioration which affect its service life and maintenance cost. Nondestructive test (NDT) methods have seen increasing use by departments of transportation to locate deterioration in bridge decks before their condition rating becomes critically low and to help plan bridge deck preservation activities. Nonetheless, uncertainty in what forms of bridge deck deterioration each NDT method can identify has posed challenges in best deploying NDT methods for deck condition assessments. Thus, in this study, a full-scale 18 ft by 31 ft reinforced concrete bridge was constructed with defects in the deck simulating reinforcing steel corrosion, delaminations, concrete deterioration, voids, and poorly constructed concrete. The deck was evaluated with ground-penetrating radar, infrared thermography, and impact-echo nondestructive technologies to evaluate their potential for defect detection. Receiver operator characteristic analysis was implemented to quantify the capability of a given NDT method to detect a particular defect. Conclusions concerning which forms of concrete bridge deck deterioration each NDT method can detect were developed. It was found that of the three NDT methods considered, impact-echo testing was the most effective to evaluate the condition of bridge decks. Impact echo was able to detect both shallow and deep delaminations as thin as 0.01 in., shallow corrosion-induced delaminations, concrete deterioration, and some of the shallow voids; however, it was unable to detect deep voids, poorly constructed concrete, and mildly deteriorated concrete.

Performance Prediction Modeling of Concrete Bridge Deck Condition Using an Optimized Approach

Developing an accurate and reliable model for concrete bridge deck deterioration rates is a significant step in improving the condition assessment process. The main goal of this study is to develop a deterioration prediction model based on the condition ratings of concrete bridge decks over the past 25 years as reported in the National Bridge Inventory (NBI) database. While the literatures have typically suggested the Markov chain method as the most common technique used in condition assessment of bridges, the analysis in this pilot study suggests that the lognormal distribution function is a better model for concrete bridge deck condition data. This paper compares the two approaches and presents a new approach that combines the more commonly used Markov chain method with the lognormal distribution function to arrive at an optimal model for predicting bridge deck deterioration rates. The prediction error in the combined model is less than each of the two models (i.e. Markov and Lognormal). Additionally, the steel structure type illustrated the highest deterioration rates within condition ratings from 8 to 4 Comparing with other types. The bridge decks that have ADT of more than 4,000 (vehicles/day) deteriorated faster than of those with ADT less than 4,000 with the same type of structure and skew angle. Bridge decks with skew angles more than 30º deteriorate faster than of those with skew angles less than 30°. Furthermore, it showed that most new Michigan concrete bridge decks may take at least 40 years before dropping gradually from 9 to 3.

A computerized hybrid Bayesian-based approach for modelling the deterioration of concrete bridge decks

Bridges are aging and deteriorating, thus, reliable deterioration modeling is regarded as one of the vital components of Bridge management systems. This article presents an automated defect-based tool to predict the future condition of the bridge decks by calibrating the Markovian model based on a hybrid Bayesian-optimization approach. The in-state probabilities are demonstrated in the form of posterior distributions, whereas the transition from a condition state to the next lower state is a function of the severities of five types of bridge defects. In the present study, the Bayesian belief network is employed to construct the likelihood function by modeling the dependencies between the bridge defects. The maximum entropy optimization is incorporated to compute the missing conditional probabilities. The proposed approach utilizes Markov chain Monte Carlo Metropolis-Hastings algorithm to derive the posterior distributions. Finally, a stochastic optimization model is designed to build a variable transition probability matrix for each five-year zone via genetic algorithm. An automated tool is programmed using C#.net programming language to facilitate the implementation of the developed deterioration model by the users. Results show that the proposed model outperformed some commonly-utilized deterioration models as per three performance indicators which are: root-mean squared error, mean absolute error, chi-squared statistic.

Mapping Ground Penetrating Radar Amplitudes Using Artificial Neural Network and Multiple Regression Analysis Methods

Bridges are aging and deteriorating. Thus, the development of Bridge Management Systems (BMSs) became imperative nowadays. Condition assessment is one of the most critical and vital components of BMSs. Ground Penetrating Radar (GPR) is one of the non-destructive techniques (NDTs) that are used to evaluate the condition of bridge decks which are subjected to the rebar corrosion. The objective of the proposed method is to develop standardized amplitude scale for bridge decks based on a hybrid optimization-decision making model. Shuffled frog leaping algorithm is employed to compute the optimum thresholds. Then, polynomial regression and artificial neural network models are designed to predict the prioritizing index based on a set of multi-criteria decision-making methods. The weibull distribution is utilized to capture the stochastic nature of deterioration of concrete bridge decks. Lastly, a case study is presented to demonstrate the capabilities of the proposed method.

Stochastic Analysis and Time-Based Modeling of Concrete Bridge Deck Deterioration

Stochastic Analysis and Time-Based Modeling of Concrete Bridge Deck Deterioration

RABIT: implementation, performance validation and integration with other robotic platforms for improved management of bridge decks

Accurate condition assessment and monitoring of concrete bridge deck deterioration progression requires both use of multiple nondestructive evaluation (NDE) technologies and automation in data collection and analysis. RABIT (robotics assisted bridge inspection tool) for bridge decks enables fully autonomous data collection at rates three or more times higher than it is typically done by a team of five inspectors using manual NDE technologies. The system concentrates on the detection and characterization of three most common internal deterioration and damage types: rebar corrosion, delamination, and concrete degradation. For that purpose, RABIT implements four NDE technologies: electrical resistivity (ER), ground-penetrating radar (GPR), impact echo (IE) and ultrasonic surface waves (USW) method. High productivity and higher spatial data resolution are achieved through the use of large sensor arrays or multiple probes for the four NDE methods. RABIT surveys also complement visual inspection by collecting high resolution images of the deck surface, which can be used for crack mapping and documentation of deck spalling, previous repairs, etc. The NDE technologies are used in a complementary way to enhance the overall condition assessment, certainty regarding the detected deterioration and better identification of the primary cause of deterioration. RABIT’s components, operation, field implementation and validation, as well as future integration with a robotic platform for minimally invasive rehabilitation, are described.

Concrete Bridge Deck Deterioration Assessment Using Ground Penetrating Radar (GPR)

Ground penetrating radar (GPR) has become an effective means for assessing deterioration in concrete bridge decks. While success has been demonstrated, the method is still not adopted widely. Constant technical development is making such high speed GPR mapping more affordable with systems more widely available and easier to deploy. The American Society for Testing and Materials (ASTM) has a standard procedure for performing bridge deck deterioration using GPR. The current standard, initially written for air-launched GPR devices and then modified to include ground-coupled GPRs, has many simplifying assumptions that could lead to fallacious evaluations. Both field experience and numerical simulations indicate that ground-coupled GPR systems are preferable to air-launched GPRs in this application, delivering larger signal-to-noise and higher spatial resolution data, which enhance extraction of both electromagnetic wave velocity and attenuation. We describe advances in analysis and interpretation that go beyond the current ASTM approach which ignores the impact of depth and other variables. We demonstrate these advances using a high speed, ground-coupled GPR system with examples of deck deterioration mapping. We describe the workflow for using GPR to evaluate the deterioration of concrete bridge decks, highlight the basic interpretation assumptions, demonstrate successful applications and discuss limitations with the methodology.

Semiempirical Methodology for Estimating the Service Life of Concrete Deck Panels Strengthened with Fiber-Reinforced Polymer

Deterioration of concrete bridge decks affects their durability, safety, and function. It is therefore necessary to conduct structural rehabilitation of damaged concrete decks by strengthening them with fiber-reinforced polymer. Of the recent studies on the strengthened structures, most have focused on static behavior; only a few studies have investigated fatigue behavior. Accurate analysis of fatigue in concrete deck performance requires a more realistic simulated moving load. This study developed a theoretical live-load model to reflect the effect of moving vehicle loads, based on a statistical approach to the measurement of real traffic loads over various time periods in Korea. It assessed the fatigue life and strengthening effect of bridge decks strengthened with either carbon fiber sheets or grid carbon fiber polymer plastic using probabilistic and reliability analyses. It used extrapolations and simulations to derive maximum load effects for time periods ranging from 1 day to 75 years. Limited fatigue tests were conducted and probabilistic and reliability analyses were carried out on the strengthened concrete bridge deck specimens to predict the extended fatigue life. Analysis results indicated that strengthened concrete decks provide sufficient resistance against increasing truck loads during the service life of a bridge.

Investigation of Likelihood of Cracking in Reinforced Concrete Bridge Decks

One of the biggest problems affecting bridges is the transverse cracking and deterioration of concrete bridge decks. The causes of early age cracking are primarily attributed to plastic shrinkage, temperature effects, autogenous shrinkage, and drying shrinkage. The cracks can be influenced by material characteristics, casting sequence, formwork, climate conditions, geometry, and time dependent factors. The cracking of bridge decks not only creates unsightly aesthetic condition but also greatly reduces durability. It leads to a loss of functionality, loss of stiffness, and ultimately loss of structural safety. This investigation consists of field, laboratory, and analytical phases. The experimental and field testing investigate the early age transverse cracking of bridge decks and evaluate the use of sealant materials. The research identifies suitable materials, for crack sealing, with an ability to span cracks of various widths and to achieve performance criteria such as penetration depth, bond strength, and elongation. This paper also analytically examines the effect of a wide range of parameters on the development of cracking such as the number of spans, the span length, girder spacing, deck thickness, concrete compressive strength, dead load, hydration, temperature, shrinkage, and creep. The importance of each parameter is identified and then evaluated. Also, the AASHTO Standard Specification limits live-load deflections to L/800 for ordinary bridges and L/1000 for bridges in urban areas that are subject to pedestrian use. The deflection is found to be an important parameter to affect cracking. A set of recommendations to limit the transverse deck cracks in bridge decks is also presented.

확장형 공통중간점법 기반 지표투과레이더를 이용한 콘크리트 교량 바닥판 열화 상태 평가

This study proposed a new non-destructive evaluation method for concrete bridge deck deterioration using ground penetrating radar (GPR). To calculate dielectric constant of the concrete bridge deck, an extended common mid-point (XCMP) method was developed for a two-layered structure using an air-coupled GPR antenna setup. The deterioration conditions of the concrete bridge deck such as deterioration depth was evaluated based on the dielectric constant and surface-to-average dielectric constant ratio of the concrete bridge deck. A GPR field test was conducted on an old concrete bridge with asphalt concrete surfacing to validate the new evaluation method. The test results showed that the newly proposed method estimated pavement thickness and deterioration depth of the concrete deck in a reasonable level.

신뢰도 분석을 통한 고속도로 교량의 바닥판 잔존 수명 예측

Korean national highway has been increased 2 times more for the past ten years because of many highway geometric improvements and new routes since 2000. According to the reasons, maintenance cost has been increased continuously. Deterioration of concrete bridge decks caused by asphalt pavement deformation occupies a high proportion of overall bridge management budget. The number of current highway bridges has reached over 7,800 in 2011, and It is difficult to determine to some future budget. This study predicted the remaining life of concrete bridge decks using the reliability analysis based on Weibull distribution. and The expected future maintenance cost was estimated.

An integrated system for bridge management using probabilistic and mechanistic deterioration models: Application to bridge decks

This paper presents a system for the maintenance management of aging highway bridges that integrates two different approaches for deterioration modeling. Probabilistic state-based/time-based models are used to predict the macro-response of bridge components for network level analysis, while reliability-based mechanistic models are used to predict the micro-response of bridge components for project level analysis. Probabilistic state-based/time-based models are developed using qualitative performance indicators (condition ratings) that are determined through visual inspections to identify the overall condition of damaged components in a bridge network. Reliability-based mechanistic models are developed using quantitative performance indicators (physical parameters) that are determined through detailed condition surveys, analytical assessments, and empirical investigations to identify the extent and severity of specific deterioration mechanisms for safety critical structures and/or highly damaged components. The condition rating data obtained from the Ministére des Transports du Québec database and the condition assessment of the Dickson Bridge in Montreal, Canada were used to demonstrate the two approaches for predicting the deterioration of concrete bridge decks at the two levels of management of the integrated system.

Concrete bridge deck deterioration model using belief networks

When deterioration of concrete is observed in a structure, it is highly desirable to determine the cause of such deterioration. Only by understanding the cause can an appropriate repair strategy be implemented to address both the cause and the symptom. In colder climates, bridge deck deterioration is often caused by chlorides from de-icing salts, which penetrate the concrete and depassivate the embedded reinforcement, causing corrosion. Bridge decks can also suffer from other deterioration mechanisms, such as alkali-silica reaction, freeze-thaw, and shrinkage. There is a need for a comprehensive and integrative system to help with the inspection and evaluation of concrete bridge deck deterioration before decisions are made on the best way to repair it. The purpose of this research was to develop a model to help with the diagnosis of concrete bridge deck deterioration that integrates the symptoms observed during an inspection, various deterioration mechanisms, and the probability of their occurrence given the available data. The model displays the diagnosis result as the probability that one of four deterioration mechanisms, namely shrinkage, corrosion of reinforcement, freeze-thaw and alkali-silica reaction, is at fault. Sensitivity analysis was performed to determine which probabilities in the model require refinement. Two case studies are included in this investigation.

Structural behavior of strengthened bridge deck specimens under fatigue loading

The deterioration of concrete bridge decks that have been directly damaged by traffic loads affects their durability, safety, and function. It is therefore necessary to strengthen the damaged concrete structures. Even though there have been many experiments performed to investigate the static behavior of strengthened structures, few experiments or analyses have considered their fatigue behavior. In this study, fatigue tests were conducted on bridge decks strengthened using various fiber-reinforced polymer plastics, such as carbon fiber sheet, glass fiber sheet, and grid-type carbon fiber reinforced plastic. All of the strengthened specimens were shown to have an improved resistance to crack propagation and better stress distributions. The Weibull distribution was adopted to analyze the fatigue life of the decks. The fatigue life limits of the strengthened bridge decks were determined at higher stress levels, and the grid-type carbon reinforced plastic specimens proved to be the most effective.

A comparison of nondestructive evaluation methods for bridge deck assessment

Concrete bridge deck deterioration is a significant problem that must be addressed to preserve highway infrastructure investments in bridges around the world. Reducing the cost of bridge deck maintenance is critical to government and private agencies responsible for maintenance of bridges. Maintenance challenges increase as many bridges begin to approach the end of their design life and traffic loads continue to increase. One means of reducing the cost of bridge deck maintenance is to accurately evaluate the condition of the structure and its constituent materials. Current methods used to evaluate deterioration of bridge decks include acoustic, electrochemical, electromagnetic, and visual inspection techniques. The purpose of this study was to assess the advantages and limitations of three available evaluation methods. The evaluation techniques included in this study were ground penetrating radar, the chain drag method, and IE. These techniques represent an important group of inspection methods currently used to evaluate in-service bridge decks. The bridge deck used in the study contains significant delaminations but exhibits virtually no outwardly visible signs of these deficiencies, so a detailed visual inspection survey of the deck was not included. Cores were taken from the bridge deck at selected locations to confirm the accuracy of the results obtained through each evaluation method. This paper presents the findings from each method and describes their respective advantages and limitations.

Modeling Bridge Deterioration Using Case-based Reasoning

Current bridge deterioration models used in bridge management systems are not successful in capturing the effects of bridge condition history on future condition, in performing “what if” analyses for different maintenance scenarios, and in accounting for the interactive effects between deterioration mechanisms of different bridge components. Moreover, these models cannot be easily updated when new data is obtained. On the other hand, bridge management systems are updated on a regular basis and thus accumulate valuable knowledge about the performance of bridges over the years. The case-based reasoning (CBR) approach could reuse this knowledge efficiently to act as a deterioration model that would overcome some of the shortcomings of current models. A new CBR system, called case-based reasoning for modeling infrastructure deterioration, was developed and utilized in building a “proof of concept” application for modeling the deterioration of concrete bridge decks using data obtained from the Canadian Province of Quebec. The performance of the CBR model showed that CBR has great potentials in predicting the future condition of infrastructure facilities.

Concrete Bridge Decks Reinforced with Fiber-Reinforced Polymer Bars

Corrosion of metallic reinforcement is a primary cause of reinforced concrete bridge deck deterioration. A potential innovative solution to this problem is to eliminate this corrosion by using nonmetallic fiber-reinforced polymer (FRP) bars. FRP bars consist of continuous fibers of glass (GFRP), aramid (AFRP), carbon (CFRP), or a combination of these (hybrid FRP), impregnated with and bound by a resin matrix through a pultrusion, braiding, or weaving manufacturing process. Each of these fiber types is linearly elastic to failure. Characteristics of FRP bars include electrochemical inertness, high tensile strength, low weight, low elastic modulus (primarily GFRP and AFRP), and low shear strength. For increased bridge deck service life, electrochemical inertness is the most important characteristic of FRP bars. The structural design of a concrete bridge deck with FRP top mat reinforcement is presented. The deck is supported on five prestressed concrete Type C beams. The 200-mm (8-in.) nominal-depth deck is designed for self-weight, bridge rails, overlay, MS18 (HS20) wheel loads, and bridge rail impact loads. The continuous beam analysis with distribution of force effect is based on AASHTO distribution formulas. The discussion includes required flexural strength, limits on calculated crack width, FRP bar bond stress characteristics, durability, and shear strength of the concrete deck reinforced with embedded FRP bars.

Fault-Tree Model of Bridge Element Deterioration Due to Interaction

Bridge engineers and bridge inspectors recognize that deterioration of one element influences the deterioration of another. The effect of this phenomenon may be crititcal if it increases the deterioration rate of the affected elements. The phenomenon is known as element interaction. The consequences of element interaction can help to explain why elements of the same type have varying deterioration rates. No practical model exists for modeling element interaction. This paper presents the use of a fault tree for qualitative and quantitative evaluation of element interaction phenomena. The fault-tree results can be used to better assess the deterioration rate and improve deterioration prediction of an element. An example of the fault-tree model for accelerated deterioration of concrete bridge decks is presented. The fault-tree model is not a deterioration model, but can be used to focus on mitigating accelerated element deterioration by certain maintenance or repair actions. Systematic implementation of the fault-tree approach presented herein must be preceded by field verification.

Studies of low-porosity concretes designed for bridge deck applications: 1. Introductory remarks, mix designs, strength development, and rheological characteristics

A major concrete problem in recent years has been premature deterioration of concrete bridge decks due to corrosion of reinforcing steel. The research reported here was designed to explore the possibility of eliminating the problem by the use of low porosity concrete. A brief review of low porosity cement systems is provided. Mix design considerations for low porosity concretes are explored. The results of laboratory trials on rheological and other features of fresh low porosity concretes are reported, and compressive strength data are provided for several different low porosity concrete systems.

Chloride Penetration and the Deterioration of Concrete Bridge Decks

Abstract The rapid deterioration of the nation's bridges is a widely recognized problem. A major contributor to this problem is bridge deck deterioration caused by chloride-induced corrosion of reinforcement. Chlorides are derived primarily from the application of roadway deicing salts. This paper synthesizes empirical data from previous studies with the diffusion theory in developing a predictive model for chloride infusion of bridge decks. The model includes the effects of subsidence cracking over the reinforcement. Primary input data consist only of average reinforcement cover, which is easily obtainable with existing instrumentation. The model is intended to serve as a useful, rational means of providing information for life-cycle costing in bridge deck rehabilitation planning studies.