Risk-Based Bridge Inspection Practices

Improving bridge safety, reliability, and the allocation of bridge inspection resources are the goals of the proposed risk-based bridge inspection practices. Currently, most bridges in the United States are inspected at a fixed calendar interval of 24 months, without regard to the condition of the bridge. Newer bridges with little or no damage are inspected with the same frequency as older, more deteriorated bridges thus creating inefficiency in the allocation of inspection resources. The proposed methodology incorporates reliability theory and expert elicitation from the Indiana Department of Transportation’s Risk Assessment Panel, developed during this research, to rationally determine bridge inspection needs. Assessments are made based on the likelihood and consequence of failure for specific bridge components. The likelihood of failure is determined through attributes based on design, loading, and condition characteristics while the consequence of failure is based on expected structural capacity, public safety, and serviceability. By combining the expressions of likelihood and consequence for each component, an optimum inspection interval for the entire bridge can be determined through the use of risk matrices. The methodology was evaluated through case studies involving Indiana bridges. Over 30 years of historical inspection reports were utilized in the back-casting process to evaluate deterioration levels and assess the adequacy of the risk criteria. Results of the case studies conducted during the research indicated that the risk analysis procedures provided suitable inspection intervals ranging from 24 to 72 months for Indiana bridges

Risk-Based Bridge Inspection Practices

Improving bridge safety, reliability, and the allocation of bridge inspection resources are the goals of the proposed risk based bridge inspection practices. Currently, most bridges in the United States are inspected at a fixed calendar interval of 24 months, without regard to the condition of the bridge. Newer bridges with little or no damage are inspected with the same frequency as older, more deteriorated bridges thus creating inefficiency in the allocation of inspection resources. Because of limited resources, it is not possible to spend the necessary time examining bridges that are in poor condition and require extra attention since equal effort is also spent on bridges in good condition. In addition, no quantitative evidence exists to suggest that the 24 month inspection interval is the appropriate interval to achieve the desired level of safety. The proposed methodology incorporates reliability theory and expert elicitation from the Indiana Department of Transportation\u27s Risk Assessment Panel, developed during this research, to rationally determine bridge inspection needs. Assessments are made based on the likelihood and consequence of failure for specific bridge components. The likelihood of failure is determined through attributes based on design, loading, and condition characteristics while the consequence of failure is based on expected structural capacity, public safety, and serviceability. By combining the expressions of likelihood and consequence for each component, an optimum inspection interval for the entire bridge can be determined through the use of risk matrices. The methodology was evaluated through case studies involving Indiana bridges. Over 30 years of historical inspection reports were utilized in the back casting process to evaluate deterioration levels and assess the adequacy of the risk criteria. Results of the case studies conducted during the research indicated that the risk analysis procedures provided suitable inspection intervals ranging from 24 to 72 months for Indiana bridges

Food Inspections and Bias in Chicago

Final project for HackCulture 2019. Use of restaurant inspection and census data to visualize relationship between restaurant inspection practices and racial diversity in Chicago to indicate potential bias in inspection practices. Data was organized by zip code to draw these correlations.Ope

Measuring Regulatory Restrictions in Logistics Services

This study measures the extent of restrictions on trade in logistics services in the ASEAN+6 economies by constructing a logistics regulatory restrictiveness index for each economy that quantifies the extent of government regulations faced by logistics service providers. This is the first study of its kind to construct a regulatory index of the entire logistics sector, which includes the main modes of international transport and customs restrictions. The indices show that large differences exist in the logistics regulatory environment of ASEAN+6 economies. Many of these economies are open to trade in logistics services, while others are relatively restrictive. Malaysia, China, Indonesia, Lao PDR, the Philippines and Vietnam are the most restrictive economies of logistics services in this region. Relatively, Singapore and Australia are the most open economies for trade in logistics services, along with Japan and New Zealand. Preliminary investigations find evidence of negative relationships between logistics regulatory restrictiveness and logistics sector performance, as measured by the World Bank's Logistics Performance Index and its sub-components. These findings support that notion that a less restricted trade environment results in better performance for the logistics sector.Logistics, Transport, Government Regulation, Trade, East Asia

Study on bridge inspections, A: identifying barriers to new practices and providing strategies for change

2021 Summer.Includes bibliographical references.Bridge inspections are one of the key elements required for a successful bridge management process to ensure adequate bridge performance. Inspections significantly inform maintenance decisions and can help in managing maintenance activities to achieve a reliable bridge network. In the United States (U.S.) routine visual inspections are required for most bridges at a maximum interval of 24-months regardless of the bridge condition. However, limitations of current bridge inspection practices impact the quality of information provided about bridge condition and the subsequent decisions made based on that information. Accordingly, the overarching goal of this research project is to support bridge inspection practices by providing a systematic and rational framework for bridge inspection planning and identifying the factors that can facilitate innovation and research transfer in the bridge inspection field. To do so, this dissertation includes three separate yet related studies; each focusing on essential aspects of bridge inspection planning. Much research in bridge inspection has been conducted to improve the inspection planning process. The first study provides an overview of current bridge inspection practices in the U.S. and conducts a systematic literature review on innovations in the field of bridge inspection planning to identify research gaps and future needs. This study provides a background on the history of bridge inspection in the U.S., including current bridge inspection practices and their limitations, and analyzes the connections between nondestructive evaluation techniques, deterioration models and bridge inspection management. The primary emphasis of the first study is a thorough analysis of research proposing and investigating different methodologies for inspection planning. Studies were analyzed and categorized into three main types of inspection planning approaches; methods that are based on: reliability, risk analysis, and optimization approaches. This study found that one of the main barriers that may be preventing the implementation of new inspection planning frameworks in practice is that the approaches presented focus on a single bridge element or deterioration mechanism in the decision-making process. Additionally, it was concluded that approaches in the literature are either complex to apply or depend solely on expert judgement. Limitations of the uniform calendar-based approach used to schedule routine inspections have been reported in the literature. Accordingly, the objective of the second study is to provide a new systematic approach for inspection planning that integrates information from bridge condition prediction models, inspection data, and expert opinion using Bayesian analysis to enhance inspection efficiency and maintenance activities. The proposed uncertainty-based inspection framework can help bridge owners avoid unnecessary or delayed inspections and repair actions, determine the inspection method, and consider more than one deterioration process or bridge component during the inspection planning process. The inspection time and method are determined based on the uncertainty and risks associated with the bridge condition. As uncertainty in the bridge condition reaches a defined threshold, an inspection is scheduled utilizing nondestructive techniques to reduce the uncertainty level. The framework was demonstrated on a new and on an existing reinforced concrete bridge deck impacted by corrosion deterioration. The results showed that the framework can reduce the number of inspections compared to conventional scheduling methods, while also reducing the uncertainty regarding the transition in the bridge deck condition and repair time. As identified through the first study, over the last two decades many researchers have focused on providing new ideas to improve conventional bridge inspection practices, however, little guidance is provided for implementing these new research products in practice. This, along with resistance to change and complexity of the proposed ideas, resulted in a lack of consistency and success in applying new technologies in bridge inspection programs across state departments of transportation (DOTs). Accordingly, the third paper presents a qualitative study set out to identify the factors that can help improve research products and accelerate change and research transfer in bridge inspection departments. This study used semi-structured interviews, written interviews, and questionnaires for data collection and engaged with twenty-six bridge staff members from different DOTs. The findings of this study are expected to be both specific to changes in bridge inspection practice and have some generalizability to other significant changes to engineering practice at DOTs. To improve research products, this study suggested that researchers need to collaborate more with DOT staff members and provide relevant research products that are not specific to certain bridge cases and can be applied on different bridges. Also, to facilitate change in transportation organizations, change leaders should focus on showing the need for change, gaining support from the FHWA, allocating the required resources, and enhancing the capacity of DOT staff members through training and effective communication. The investigation also presented participants' opinions on some of the aspects related to conventional inspection practices such as their support of a uniform inspection interval over a variable interval, and the main barriers limiting the use of NDE methods. This study contributes to the body of knowledge in the bridge inspection field by providing a new inspection planning approach that depends on the uncertainty and the risks associated with the bridge condition and uses both computational methods and expert judgment allowing bridge owners select inspection time and method while considering more than one deterioration process or bridge element. In addition, this study presents some of the factors that can help reduce the gap between research and practice and facilitate innovation and change in transportation organizations

Flaw detection with ultrasonic backscatter signal envelopes

Ultrasound is a prominent nondestructive testing modality for the detection, localization, and sizing of defects in engineering materials. Often, inspectors analyze ultrasonic waveforms to determine if echoes, which stem from the scattering of ultrasound from a defect, exceed a threshold value. In turn, the initial selection of the threshold value is critical. In this letter, a time-dependent threshold or upper bound for the signal envelope is developed based on the statistics governing the scattering of ultrasound from microstructure. The utility of the time-dependent threshold is demonstrated using experiments conducted on sub-wavelength artificial defects. The results are shown to enhance current nondestructive inspection practices

Bridge inspection practices using non-destructive testing methods

Non-Destructive Testing (NDT) methods have been developed and employed as a means of rapid and effective structural inspection. Despite the various kinds of NDT methods developed for bridge inspection, not much study has been performed on their usage and effectiveness at a practical level. This paper presents an evaluation of NDT methods to identify how they are implemented in state agencies in the U.S. The findings and analysis presented herein were based on the results obtained from a survey questionnaire, targeted at Departments of Transportation (DOTs) in all U.S. states and territories. The survey questionnaire was initiated to clarify multiple issues regarding NDT implementation, such as identifying the types of inspection that involve NDT methods, bridge components that are most likely to be inspected with NDT, effective methods of inspecting concrete or steel structures, and so on. A total of 40 state agencies participated in the survey processing, and the major findings obtained from the states are illustrated and explained in detail in this paper. In addition, bridge defects that are hard to detect in the course of inspection and current research efforts to develop novel NDT methods were investigated

UAV-Based Bridge Inspection and Computational Simulations

The use of Unmanned Aerial Vehicles (UAV), commonly known as drones, has significantly increased in the field of civil engineering due to the poor condition of the United States’ infrastructure. The American Society of Civil Engineers (ASCE) recently reported that more than 9.1% of the United States’ bridges were structurally deficient and required attention and maintenance to ensure appropriate structural performance. Meanwhile, current practices are expensive and unsafe for bridge inspectors, requiring innovative and safer methods for the study of bridges. The goal of this paper was to identify better techniques to not only inspect, quantify, and determine the effect of damage on bridges to minimize the risk for inspectors, but also to determine their live-load performance using UAV-based computational simulation updating techniques. To accomplish the objective, an extensive literature review and survey to state departments of transportation (DOTs) was conducted to gain technical knowledge on current UAV-based inspection practices. To evaluate the efficiency of the UAV, the Keystone Interchange Bridges (i.e., Keystone Wye timber arch bridge and timber girder bridge) in the Black Hills National Forest near the city of Keystone, South Dakota (SD), were studied. To provide a more systematical and efficient UAV-enabled bride inspection method, a five-stage recommended bridge inspection protocol was developed. A UAV-image-based bridge damage quantification protocol involving image quality assessment and image-based damage measurement was recommended. Finally, using the damage information form the inspection and quantification of the bridges, a Finite Element (FE) model to determine the live-load performance of the Keystone Wye timber arch bridge in terms of Distribution Factors (DF) and Load Rating Factors (RF) was developed. It was concluded that the UAV served as an effective tool to supplement current inspection practices and provide damage information that can be used to update FE models to rationally estimate bridge performance

Assessment of state-of-the-art of in-service inspection methods for graphite epoxy composite structures on commercial transport aircraft

A survey was conducted to determine current in-service inspection practices for all types of aircraft structure and particularly for advanced composite structures. The survey consisted of written questionnaires to commercial airlines, visits to airlines, aircraft manufacturers, and government agencies, and a literature search. Details of the survey including visits, questions asked, a bibliography of reviewed literature and details of the results are reported. From the results, a current in-service inspection baseline and a preliminary inspection program for advanced composite structures is documented as appendices to the report

How to find and understand development problems and learning challenges in organic vegetable farming?

Laura Seppänen's doctoral dissertation in agroecology, using an approach derived from cultural historical activity theory, examines the developmental problems and learning challenges in organic vegetable farming