Field Investigation And Statistical Modeling Of In-service Performance Of Concrete Bridge Decks In Pennsylvania
Author | : Amir Manafpour |
Publisher | : |
Total Pages | : |
Release | : 2015 |
ISBN-10 | : OCLC:943065087 |
ISBN-13 | : |
Rating | : 4/5 (87 Downloads) |
Book excerpt: 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.