INTRODUCTION OF NON-DESTRUCTIVE HIGHWAY INSPECTION METHODS USING HIGH DEFINITION VIDEO AND INFRARED TECHNOLOGY

摘要

In these days of severe budget restrictions for many highway agencies worldwide, it hasbecome increasingly difficult for highway department managers and engineers to respondto the ever increasing maintenance and rehabilitation demands of their deterioratinghighway structures. In order to make timely and appropriate maintenance andrehabilitation decisions, constant monitoring of structural conditions is necessary. Whilemost agencies recognize the importance of timely bridge inspections such programs tendto be time consuming and expensive.In Japan, bridge owners face this dilemma of recognizing the critical importance of timelystructure inspections while concurrently facing budget pressures brought on in part by thehigh labor costs and time requirements of their traditional visually oriented bridgeinspection programs. To address this problem, Japanese engineers have worked todevelop more efficient, economical and safer bridge inspection methods and proceduresUnder these circumstances, one of Japan?s major toll road operators (NEXCO-West) hasbeen able to reduce highway structure inspection costs by developing and introducing aninnovative highway inspection technical approach that uses a combination of highdefinition video (HDV) and infrared (IR) thermographic technology. High definition videorecords the surface condition of concrete structures. Recorded data is analyzed by imageprocessing to determine crack widths and length on concrete surfaces Infrared imagingsupports a thermographic assessment of structural integrity. In general, thermographicassessments involve analyzing structural integrity through an analysis of variations in astructural element?s temperature at different times of the day; recognizing that damaged ordeteriorating structural elements demonstrate different temperature variation gradientsthan do sound structural elements. Combining HDV and IR data enables an accurateassessment of a bridge?s structural integrity.This paper describes these inspection methods using HDV and infrared technologies andintroduces some examples of practical on-site application to highway bridgesuperstructures. The technology can provide a powerful tool for engineers responsible fordeveloping highway maintenance strategies and contribute to efficient and smartinfrastructure management.