Active dimensional quality assessment of precast concrete using 3D laser scanning

Quality assessment of precast concrete panels is an important factor that affects overall quality of construction. As prefabrication becomes popular at construction sites, demands for automatic and accurate inspections of the dimensions of the precast concrete panels have increased. Current techniques for measuring the dimensions of precast concrete panels, however, heavily rely on qualified inspectors and are time- and labor-demanding. To overcome these limitations, a dimensional measurement technique for precast concrete panels is proposed using a 3D laser scanner. For autonomous implementation of the dimensional measurement, a new feature extraction algorithm of extracting only boundary points of the precast concrete panels is developed. To increase the measurement accuracy, a compensation model is employed to account for the dimension losses caused by an intrinsic limitation of laser scanners. This study focuses on measurements of length, width and squareness of precast concrete panels in a non-contact and speedy manner. Experimental validations on actual precast slabs are conducted to verify the applicability of the proposed dimensional measurement technique for precast concrete panels.