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With a large number of aging transportation infrastructure assets in North America and the growing problem of deterioration across the globe, managing these assets have been the subject of ongoing research. There is an overwhelming amount of maintenance and rehabilitation works to be done and selecting a suitable maintenance, repair or replacement (MRR) strategy is one of the most challenging tasks for decision makers. Limited budget and resources are even making the decision making process more challenging. Maintaining infrastructure to the highest possible condition while investing the minimal amount of money has promoted innovative contracting approaches. Transportation agencies have increased private sector involvement through long term performance-based maintenance contracts or what is called Performance-Based Contracting. PBC is a type of contract that pays a contractor based on the results achieved, not on the methods for performing the maintenance work. By looking into the literature, it is observed that agencies are expanding the amount of contracting they do in order to maintain and achieve a better standard of infrastructure facilities. Therefore, the objective of this paper is to study and review performance-based contracting for transportation infrastructure with emphasis on bridge assets.

Bridge condition assessment is an essential step in bridge management. To ensure safety and serviceability of bridge infrastructure, accurate condition assessment is needed to provide basis for bridge Maintenance, Repair, and Replacement (MRR) decisions. In Canada and the United States, visual inspection is the common practice to evaluate a bridge condition. Meanwhile, this practice is limited to detect surface defects and external flaws. For subsurface defects, Non-Destructive Testing and Evaluation (NDT&E) technologies are being used to supplement visual inspection. This paper reviews the common practices in assessing concrete bridges’ conditions and discusses the limitations of available condition assessment models. Further, this research studies six NDT&E techniques and establishes a set of selection criteria which is utilized to compare each technique in terms of providing the best inspection results. Based on the comparison, it is found that Ground Penetrating Radar (GPR) appears to be the most appropriate NDT&E techniques for inspection of concrete bridges. Thus, this paper recommends integrating GPR technology with the dominant visual inspection practice in order to establish a more accurate overall bridge condition rating system where surface and subsurface defects are assessed.

In this study, the applications and the limitations of the Ground-penetrating radar (GPR) investigation have been addressed with the main objective of improving the efficient GPR application of subsurface surveys on Korean expressways. The depth of investigation and detection performance of anomalous objects have been studied using two different types of multichannel GPR on the Korean Expressway Corporation's nondestructive testing testbed for subsurface detection. Based on the field survey, it was found that utilizing the plane view by depth, cross-sectional and longitudinal profile data of the multichannel GPR simultaneously, analysis and evaluation of the GPR signals are more efficient and practical. Although there was a difference in the frequency of use, the precision difference between two GPR is almost similar in the investigation depth and detection performance of the pavement subsurface anomaly. Under an asphalt concrete standard pavement section, the effective depth of cavity detection is 1–1.5 m, while detection under concrete pavement is less than 1.0 m. In addition, there is still a need to calibrate depths using field cores when constructing a 3D underground facility map. [ABSTRACT FROM AUTHOR]