Grove J.,FHWA and Global Consulting Inc. |
Jones K.,00 Lincoln Way |
Ye D.,Fugro |
Gudimettla J.M.,FHWA and Global Consulting Inc.
Transportation Research Record | Year: 2012
Magnetic pulse induction can be used to determine the thickness of concrete pavement in a nondestructive manner. This induction provides the same level of accuracy and can save time and money for state agencies when compared with coring the pavement for thickness determination. The MIT-SCAN-T2 is a commercially available device that uses magnetic pulse induction to measure pavement thickness. The technology and operation of this device are described. Field experience from various states is provided. The accuracy and the repeatability, when compared with measuring core lengths, are good on the basis of data collected to date. The advantages of this nondestructive testing are presented. A specification developed by the Iowa Department of Transportation is included. The paper also includes a discussion of other issues that may be raised when this technique is used or there is ongoing work related to implementation.
Gucunski N.,Rutgers University |
Romero F.,Rutgers University |
Kruschwitz S.,BAM Federal Institute of Materials Research and Testing |
Feldmann R.,BAM Federal Institute of Materials Research and Testing |
And 2 more authors.
Transportation Research Record | Year: 2010
Reinforced concrete bridge decks are exposed to several types of deterioration processes: Corrosion, alkali-silica reaction, carbonation, shrinkage, freeze-thaw actions, and so forth. The most commonly found problem is corrosion-induced bridge deck delamination. Previous studies have shown that surveys of bridges relying on a single nondestructive evaluation (NDE) technology provide limited information about the condition of concrete bridge decks. To overcome limitations of individual technologies, a complementary approach using several NDE technologies should be used in bridge deck evaluation. The presented approach utilizes a suite of NDE technologies, namely, impact echo (IE), ultrasonic surface waves (USW), ground-penetrating radar (GPR), half-cell potential (HCP), and electrical resistivity (ER). The suite of NDE technologies was implemented in the evaluation of bridge decks on nine bridges in Iowa. The NDE was complemented by ground-truth measurements on the cores extracted from all nine bridge decks. Condition assessment with the five NDE technologies has clearly shown their advantages and limitations. For example, the GPR surveys provided assessment of concrete deterioration at relatively high speeds of data collection. In contrast, IE provided high accuracy in detection and characterization of delaminations in the deck but at a lower testing speed. HCP and ER tests provided assessment of the likelihood of corrosion, whereas the USW test provided accurate assessment of the effects of deterioration processes and defects on mechanical properties, primarily the degradation of the elastic modulus. Most important, the survey showed the advantages of use of multimodal NDE surveys in the comprehensiveness of condition assessment of concrete bridge decks.
Hallmark S.,Iowa State University |
Orellana M.,Iowa State University |
McDonald T.,Iowa State University |
Fitzsimmons E.,Iowa State University |
Matulac D.,00 Lincoln Way
Transportation Research Record | Year: 2010
Red light running (RLR) is a serious safety issue that results in more than 100,000 crashes and 1,000 fatalities annually. In Iowa, RLR accounts for 21% of total crashes at signalized intersections and 35% of fatal and major-injury crashes at signalized intersections, according to data analyzed from 2001 to 2006. As transportation agencies struggle to address RLR, they turn increasingly to the use of red light camera enforcement. In Iowa, three communities currently use RLR camera enforcement. One of the communities, Davenport, installed cameras in 2004; 2 years of crash data after installation were available for analysis. A Bayesian statistical before-and-after analysis was used to evaluate the effectiveness of Davenport's RLR cameras. The analysis included control intersections. The results of the analysis indicated that the cameras were effective in reducing total crashes and RLR crashes. Results also indicated that rear-end crashes related to RLR did not increase at camera-enforced intersections.
Phares B.,Bridge Engineering Center |
Lu P.,00 Lincoln Way |
Wipf T.,Iowa State University |
Greimann L.,Bridge Engineering Center |
Seo J.,Bridge Engineering Center
Transportation Research Record | Year: 2013
Several of the steps, iterations, and refinements required to develop one of the many pieces of the structural health monitoring (SHM) system puzzle are described. These steps include devising initial concepts, alpha testing, analytical investigation, beta testing, concept upgrades, and field evaluations. Although not necessarily a blueprint for the development of such systems, the report serves as a case study for taking an initial concept through multiple steps that culminate in a validated approach. As SHM becomes a more widely adopted and accepted bridge evaluation protocol, it will be imperative that developers understand the steps required to develop such systems. The work presented is one example of such a process.