The use of aerial laser scanning to detect change in infrastructure and buildings after major disasters has become increasingly common in recent years to help prioritize interventions. More recent efforts are being invested to apply laser scanning in the assessment and structural health monitoring of buildings to simplify and quicken building damage surveys by the automatic detection of defects and deformations. Technology application must, however, be done in cognizance of equipment constraints regarding scan angle, sampling size, and beam width. This article reports a series of laboratory and field experiments designed to begin to quantify and minimise the possible errors for effective defect detection via terrestrial laser scanning during surveying. Varying geometric positions that cause either over-or under-prediction of crack thickness and length as a function of both standoff distance and angle of obliquity between the scanner and the defect are presented. These may over-predict horizontal crack thickness by 15 mm and failing to detect others. To help minimise such errors, a standoff distance of 12-15 m with a maximum obliquity of 45˚ between the scanner and target object are recommended.

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Standard-Nutzungsbedingungen:Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden.Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. This paper develops a new measure of state and local fiscal sustainability called the "trend gap," which is based on socioeconomic and other fundamental factors and removes the shortterm influence of the business cycle. The paper estimates the trend gap and finds that the nationwide per capita trend gap has been on a growing path over the past three decades, a different conclusion than found in previous studies. Social insurance and income maintenance programs have played a major role in the growth of the trend gap, while pension and other post-employment benefits (OPEB) plans have become increasingly important in driving it up. In addition, there are large and growing disparities in the trend gap across states. Terms of use: Documents in EconStor may

Abstract:This paper develops a new measure of state and local fiscal sustainability called the "trend gap," which is based on socioeconomic and other fundamental factors and removes the shortterm influence of the business cycle. The paper estimates the trend gap and finds that the nationwide per capita trend gap has been on a growing path over the past three decades, a different conclusion than found in previous studies. Social insurance and income maintenance programs have played a major role in the growth of the trend gap, while pension and other post-employment benefits (OPEB) plans have become increasingly important in driving it up. In addition, there are large and growing disparities in the trend gap across states.

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