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.

Phase 1 Report on the Development of Predictive Model for Bridge Deck Cracking and Strength Development

Phase 1 Report on the Development of Predictive Model for Bridge Deck Cracking and Strength Development
Author:
Publisher:
Total Pages: 64
Release: 2009
Genre: Bridges
ISBN:

Early-age cracking, typically caused by drying shrinkage (and often coupled with autogenous and thermal shrinkage), can have several detrimental effects on long-term behavior and durability. Cracking can also provide ingress of water that can drive chemical reactions, such as alkali-silica reaction (ASR) and sulfate attack. Because of the problems associated with cracking observed in bridge decks, and the impact of early-age cracking on long-term performance and durability, it is imperative that bridge decks be constructed with minimal early-age cracking and that exhibit satisfactory long-term performance and durability. To achieve these goals for bridges in the state of Texas, a research team has been assembled that possesses significant expertise and background in cement chemistry, concrete materials and durability, structural performance, computational mechanics (finite difference/element), bridge deck construction and maintenance, monitoring of in-site behavior of field structures, and the development of test methods and specifications aimed at practical implementation by state highway departments. This proposal describes a laboratory- and field-based research program aimed at developing a bridge deck cracking model that will ultimately be integrated into ConcreteWorks, a suite of software programs developed for TxDOT by this same research team.

Assessment of the Cracking Problem in Newly Constructed Bridge Decks in Colorado

Assessment of the Cracking Problem in Newly Constructed Bridge Decks in Colorado
Author: Yunping Xi
Publisher:
Total Pages: 83
Release: 2003
Genre: Bridges
ISBN:

Early age cracking on concrete bridge decks has been experienced by many state departments of transportation (DOTs). In Colorado the cracking problem on newly constructed bridge decks has not been completely solved. In this study, the extent and causes of the cracking problem were investigated, and necessary changes to alleviate the cracking problem were identified. To achieve these goals, current Colorado Department of Transportation (CDOT) practice was reviewed and compared with other DOTs practices for construction of bridge decks. A database analysis of field inspection results was performed.

Phase I: Minimization of Cracking in New Concrete Bridge Decks

Phase I: Minimization of Cracking in New Concrete Bridge Decks
Author: Nicole Duffala
Publisher:
Total Pages: 85
Release: 2016
Genre: Concrete bridges
ISBN:

Cracking of newly constructed high-performance concrete (HPC) bridges is a problem recognized nationwide and the Nevada Department of Transportation has been plagued with this distress in their HPC concrete bridge decks. This research effort is a strategic attempt to reduce or eliminate random cracking that is caused by restrained shrinkage in new concrete bridge decks constructed in Nevada. The overall objective will be achieved through a three phase research program of which the results of Phase I are being reported in this document. Phase I research findings provide a synthesis of state, regional, and national practices and knowledge on factors contributing to HPC bridge deck cracking. With respect to materials and mixture proportioning, the overwhelming conclusion is that the shrinkage of the concrete mixture, especially at early-ages, must be reduced and the concrete’s resistance to cracking must be Improved. A rigorous, Phase II laboratory experiment was designed and is presented herein. This Phase II laboratory experiment focuses on local materials and will assess the properties of concrete mixtures that are related to early-age drying shrinkage restraint cracking. Ultimately, these research findings could be used to revise standard specifications and special provisions for Nevada DOT bridge decks and eventually reduce the overall incidence of restraint cracking due to concrete drying shrinkage.