Field Investigation And Statistical Modeling Of In-service Performance Of Concrete Bridge Decks In Pennsylvania

Field Investigation And Statistical Modeling Of In-service Performance Of Concrete Bridge Decks In Pennsylvania
Author: Amir Manafpour
Publisher:
Total Pages:
Release: 2015
Genre: Concrete bridges
ISBN:

The condition of the nation's aging infrastructure has been of the highest concern in recent decades. FHWA estimates that $20.5 billion will need to be invested annually in order to eliminate the United States' bridge deficient backlog by 2028. Bridge deck deterioration is one of the primary concerns and cost factors for transportation agencies. Pennsylvania has one of the highest percentages of structurally deficient and functionally obsolete bridges in the USA. This thesis is structured in two papers/studies related to the performance of concrete bridge decks in Pennsylvania.The first paper summarizes the results of expert survey and field investigations of early-age bridge deck cracking in the Commonwealth of Pennsylvania. The goal was to use field data to identify factors that contribute to or reduce early-age cracking in concrete bridge decks and to assess the effect of cracks on long-term durability performance of bridge decks. First, a survey of 71 PennDOT personnel was conducted to collect and document their experience with early-age cracking and its relation to long-term deck performance. Next, inspection data from 203 bridge decks were collected and analyzed to evaluate the effect of concrete mixture proportions and properties, construction methods, and rebar type on the propensity to experience early-age deck cracking. The results suggest that limiting the total cementitious materials content (e.g., to 620 pcy) and the maximum compressive strength (e.g., to 5000 psi at 28 days) is advisable to reduce deck cracking. In addition, epoxy-coated rebar showed good corrosion resistance even in cracked concrete.The second paper focuses on evaluating the deterioration behavior of concrete bridge decks over time. Considering the stochastic nature of infrastructure deterioration, studies have found that time-based probabilistic models are the most accurate for performance prediction. In this paper, a semi-Markov time-based model based on Accelerated Failure Time (AFT) Weibull fitted-parameters is developed. For this purpose, approximately 30 years of in-service performance data for over 22,000 bridges in Pennsylvania were utilized. The proposed approach attempts to relate deck deterioration rates to various explanatory variables such as structural specifications and environmental factors. Furthermore, the effect of remediation on bridge deck deterioration and service life are also evaluated and quantified based on in-service performance data.

Statistical Modeling of United States Highway Concrete Bridge Decks

Statistical Modeling of United States Highway Concrete Bridge Decks
Author: Omar Ghonima
Publisher:
Total Pages: 261
Release: 2017
Genre:
ISBN: 9780355255799

As the backbone of the US transportation system, bridges are also its most visible part. There are over 600,000 bridges across all US states ensuring network continuity. In order to optimize such activities and use the available monies most effectively, a solid understanding of the parameters that affect the performance of concrete bridge decks is critical. The National Bridge Inventory (NBI), perhaps the single-most comprehensive source of bridge information, gathers data on more than 600,000 bridges in all fifty states, the District of Columbia, and the Commonwealth of Puerto Rico. Recently there has been a growing interest in analyzing the NBI database. The NBI uses visual inspection, a commonly practiced damage detection method, to rate bridge decks. Focusing on concrete highway bridge deck performance, the present study developed a nationwide database based on NBI data and other critical parameters, such as bridge age, deck area, climatic regions, and distance from seawater. Additionally, two new performance parameters were computed from the available concrete bridge deck condition ratings (CR): Time-in-condition rating (TICR) and deterioration rate (DR). Following the aggregation of all these parameters to form a nationwide database, filtering and processing were performed. Approaches to dealing with inconsistencies and missing data are proposed as well. After developing the nationwide database this research presents network-level, one-way statistical relationships to get a better understanding of the parameters. ☐ Next, a data mining technique on the nationwide database was used to analyze the data. Data mining is a discovery procedure to explore and visualize useful but less-than-obvious information or patterns embedded in large collections of data. Given the amount and variety of parameter types in a large data set such as that of the nationwide database, using traditional clustering techniques for discovery is impractical. As a consequence, this research has applied a novel data discovery tool called two-step cluster analysis to visualize associations between concrete bridge deck design parameters and bridge deck condition ratings. Two-step cluster analysis is a powerful knowledge discovery tool that can handle categorical and interval data simultaneously and is capable of reducing dimensions for large data sets. The two-step cluster analysis is a useful tool for bridge owners and agencies to visualize general trends in their concrete bridge deck condition data and support them in their decision-making processes to effectively allocate constrained funds for maintenance, repair, and design of bridge decks. ☐ Understanding the attributes of bridge deck performance is central to asset management. This research attempts to characterize how various environmental and structural parameters affect bridge deck performance by employing a binary logistic regression. The logistic model shows the relationship between a dependent variable (lowest vs. highest bridge deck deterioration) and the relative importance of a number of independent variables selected for this study (predictor variables). Observations of extreme bridge deck deterioration taken from the nationwide database were used in the model. Bridge deck deterioration was computed as the decrease in CR over time. Maintenance responsibility fulfillment, functional classification of inventory route, design and construction type, average daily truck traffic, climatic regions, and distance to seawater, were all used as independent variables. Our application of a binary logistic regression model for bridge deck deterioration provides practical insight regarding how certain parameters influence bridge deck performance. ☐ A leading factor in structural decline of highway bridges is the deterioration of concrete decks. Thus, a method to forecast bridge deck performance is vital for transportation agencies to allocate future repair and rehabilitation funds. The objective of this study was the development of a nationwide CR deterioration model based on the nationwide database through the use of a Bayesian statistical approach that predicts probability of CR decrease. In addition to CR data, the impact of other governing factors on CR decrease are shown in the paper, such as average daily truck traffic (ADTT), maintenance responsibility fulfillment, deck structure type, and regional climate effect. One singular advantage of this method is that it can be continually updated as additional NBI information becomes available. Moreover, the results of this model can be used as prior data in future Bayesian studies. The results presented in this study, by providing a better idea of how US concrete bridge decks are performing based on the NBI data, are intended to furnish a progressive bridge management system. ☐ Results yielded by each of the analysis above will encourage future researchers to add other crucial parameters not contained in the nationwide database such as structural design characteristics (e.g., minimum deck thickness), construction practices (e.g., curing practices), specifications (e.g., water-to-cement ratio), and other notable factors (e.g., application of deicing salts). Furthermore, analyze the nationwide database in various statistical application areas leading to more accurate understating of the factors affecting bridge deck deterioration and enhanced deck deterioration prediction models.

Deterioration Prediction Modeling for the Condition Assessment of Concrete Bridge Decks

Deterioration Prediction Modeling for the Condition Assessment of Concrete Bridge Decks
Author: Aqeed Mohsin Chyad
Publisher:
Total Pages: 138
Release: 2018
Genre: Concrete bridges
ISBN:

Bridges are key elements in the US transportation system. There are more than six hundred thousand bridges on the highway system in the United States. Approximately one third of these bridges are in need of maintenance and will cost more than $120 billion to rehabilitate or repair. Several factors affect the performance of bridges over their life spans. Identifying these factors and accurately assessing the condition of bridges are critical in the development of an effective maintenance program. While there are several methods available for condition assessment, selecting the best technique remains a challenge. Therefore, developing an accurate and reliable model for concrete bridge deck deterioration is a key step towards improving the overall bridge condition assessment process. Consequently, the main goal of this dissertation is to develop an improved bridge deck deterioration prediction model that is based on the National Bridge Inventory (NBI) database. To achieve the goal, deterministic and stochastic approaches have been investigated to model the condition of bridge decks. While the literatures have typically proposed the Markov chain method as the best technique for the condition assessment of bridges, this dissertation reveals that some probability distribution functions, such as Lognormal and Weibull, could be better prediction models for concrete bridge decks under certain condition ratings. A new universal framework for optimizing the performance of prediction of concrete bridge deck condition was developed for this study. The framework is based on a nonlinear regression model that combines the Markov chain method with a state-specific probability distribution function. In this dissertation, it was observed that on average, bridge decks could stay much longer in their condition ratings than the typical 2-year inspection interval, suggesting that inspection schedules might be extended beyond 2 years for bridges in certain condition rating ranges. The results also showed that the best statistical model varied from one state to another and there was no universal statistical prediction model that can be developed for all states. The new framework was implemented on Michigan data and demonstrated that the prediction error in the combined model was less than each of the two models (i.e. Markov and Lognormal). The results also showed that average daily traffic, age, deck area, structure type, skew angle, and environmental factors have significant impact on the deterioration of concrete bridge decks. The contributions of the work presented in this dissertation include: 1) the identification of the significant factors that impact concrete bridge deck deterioration; 2) the development of a universal deterioration prediction framework that can be uniquely tailored for each state’s data; and 3) supporting the possibility of extending inspection schedules beyond the typical 2-year cycles. Future work may involve: 1) evaluating each of the factors that impact the deterioration rates in more depth by refining the investigation ranges; 2) investigating the possibility of revising the regular bridge deck inspection intervals beyond the 2-year cycles; and 3) developing deterioration prediction models for other bridge elements (i.e. superstructure and substructure) using the framework developed in this dissertation.

Relating Material Properties to Exposure Conditions for Predicting Service Life in Concrete Bridge Decks in Indiana

Relating Material Properties to Exposure Conditions for Predicting Service Life in Concrete Bridge Decks in Indiana
Author: Vinit Barde
Publisher: Purdue University Press
Total Pages: 220
Release: 2007-12-01
Genre: Transportation
ISBN: 9781622601295

Bridges in the US are deteriorating at an alarming rate. It has been estimated that transportation agencies across the US invest more than 5 billion dollars on concrete bridge repair and renovation annually. To meet the needs of transportation industry, high performance concrete (HPC) has been developed for the construction of bridges. However, the link between material properties and field performance is not completely established. Goodspeed et al. [1996] defined the performance of concrete using four material parameters that describe durability and four material parameters that describe mechanical properties. However, material properties alone cannot entirely define field performance. Rather some consideration is needed to quantify the conditions to which the concrete will be exposed. The exposure conditions vary based on the geographical location. This work relates material properties with the exposure conditions typical of those in the state of Indiana to estimate the performance of concrete bridge decks. The exposure conditions in the state of Indiana were assessed. Specifically, temperature, rainfall, wetting events, freeze thaw cycles, and relative humidity have been classified. To assess the variation in these parameters across the state, contour maps were developed using information from cities in the state of Indiana as well as cities in surrounding states. The eight parameters suggested by Goodspeed et al. [1996] were reviewed. Three key distresses behavior (chloride ingress, freezing and thawing, and shrinkage cracking) have been investigated in depth. Relationships have been developed to relate measured material properties (from the results of AASHTO/ASTM tests) with the predicted performance of the concrete structure under different exposure condition. First, a model is presented that relates the results of Rapid Chloride Permeability Test (RCPT) with the anticipated service life of bridge deck against corrosion due to chloride ingress. Second, a model is presented that relates results of sorptivity, porosity, and critical saturation with the anticipated service life of concrete exposed to freezing and thawing. Third, a model is presented that relates the shrinkage of concrete with the potential for premature cracking. The results of each of the models have been presented for conditions that are typical of the state of Indiana.

High Performance Concrete Bridge Deck Investigation

High Performance Concrete Bridge Deck Investigation
Author: David W. Mokarem
Publisher:
Total Pages: 724
Release: 2009
Genre: Bridges
ISBN:

In 1993, the Federal Highway Administration (FHWA) initiated a national program to implement the use of high-performance concrete (HPC) in bridges. The program included the construction of demonstration bridges throughout the United States. The construction of these bridges has provided a large amount of data on the use of HPC. In addition, construction of these bridges provided opportunities to learn more about the placement and actual behavior of HPC in bridges. The overall objective of this project was to inspect, assess, and evaluate the in-service condition of those bridge decks.

High performance concrete bridge deck investigation

High performance concrete bridge deck investigation
Author: Benjamin A. Graybeal
Publisher:
Total Pages: 4
Release: 2009
Genre: Bridges
ISBN:

This document is a technical summary of the unpublished Federal Highway Administration report, High Performance Concrete Bridge Deck Investigation, available only through the National Technical Information Service (NTIS). NTIS Accession No. of the report covered in this TechBrief: PB2009 115497. This TechBrief provides a summary of an investigation that assessed the performance of high performance concrete (HPC) bridge decks. HPC is a concrete designed to meet a performance specification. Many definitions of HPC have been proposed over the past 15 to 20 years; one to note is the definition proposed by Goodspeed and later expanded by Russell and Ozyildirim that offers a series of strength and durability related performance characteristics. It recommends that the desired performance of the concrete should be considered and that the performance characteristics should then be set accordingly. Example performance characteristics toward which concrete properties may be focused include chloride penetration, shrinkage, compressive strength, and freeze/ thaw deterioration resistance.

Masters Theses in the Pure and Applied Sciences

Masters Theses in the Pure and Applied Sciences
Author: Wade H. Shafer
Publisher: Springer Science & Business Media
Total Pages: 307
Release: 2013-11-21
Genre: Science
ISBN: 1475757794

Masters Theses in the Pure and Applied Sciences was first conceived, published, and dis· seminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) *at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the ac· tivity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all concerned if the printing and distribution of the volume were handled by an international publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Corporation of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 20 (thesis year 1975) a total of 10,374 theses titles from 28 Canadian and 239 United States universities. We are sure that this broader base for theses titles reported will greatly enhance the value of this important annual reference work. The organization of Volume 20 is identical to that of past years. It consists of theses titles arranged by discipline and by university within each discipline.