Validation of terrestrial laser scanning and photogrammetry techniques for the measurement of vertical underclearance and beam geometry in structural inspection of bridges

This research shows a novel methodology based on the application of terrestrial laser scanning and photogrammetry techniques as auxiliary metric tools for bridge inspections procedures. These methodologies are validated throughout a case study where the minimum underclearance and the overall geometry of a prestressed concrete beam are obtained. Data obtained are compared with high accurate measurements provided by a total station. Results show a good agreement for beam geometry with high statistical correlation coefficients. Minimum vertical underclearance also shows a good agreement for all the systems, which appears good enough due the metric tolerances required in these inspection works. (C) 2012 Elsevier Ltd. All rights reserved.