Laser-scan based pose monitoring for guiding erection of precast concrete bridge piers

Abstract

Precast construction creates cost-effective structures by rapidly assembling prefabricated components. The emerging trend in increasing weights and scales of precast members, poses new challenges on installation quality. This study proposes an efficient and accurate pose measurement technique for guiding the erection of precast bridge piers using terrestrial laser scanning techniques. An arbitrary position of the scanner is allowed which is pre-calibrated by a single scan before the erection. For data analysis, a novel coarse-to-fine registration method is proposed to automatically align the scan model with the design model. A feature descriptor based on two-dimensional local kernel density map is used for fast coarse registration. An objected-oriented iterative closest point (ICP) registration based on virtual scan generator and nearest neighbour search is adopted for accurate fine registration. The proposed system was evaluated in the construction of an expressway viaduct and shows the potential for improving the installation efficiency and accuracy.