Use of Point Clouds to Enhance Bridge Deck Quality Control

Abstract: This paper presents the findings of a research project developed to evaluate the effectiveness and efficiency of implementing point cloud data collected throughout the construction process of a concrete bridge deck to enhance its quality control protocol. A sequence of point clouds was generated on a concrete bridge deck during construction to evaluate (1) the location of the reinforcing bars, (2) the thickness of the slab, and (3) the top surface of the casted concrete deck. To achieve this, the scans were performed (a) once the formwork was completed, (b) after the reinforcing steel was placed, and (c) after the concrete was cast. The scans revealed an otherwise unforeseen construction error. During the construction process, one of the supports of the Bidwell machine rotated, causing the level of that support to decrease, which had a local impact on the slab thickness. As a result, the concrete slab had a 1 in. less thickness at the affected location, causing the top rebars to have a thinner cover. The concrete deck was subjected to continuous non-destructive testing and evaluation to monitor its progressive deterioration. The long-term monitoring of the deck revealed that the deterioration initiated at the location where the rebars had less top cover. This was certified through the results of the NDE collected. The use of point clouds to evaluate the construction process helped the early detection of a potentially vulnerable area. Implementing this practice in the field can aid in identifying defects from the inception so that prompt action can be taken and early deterioration can be avoided.