Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Image-based 3D Mapping of Rebar Location for Automated Assessment of Safe Drilling Areas Prior to Placing Embedments in Concrete Bridge Decks

Published

Author(s)

Mani Golparvar-Fard, Behshad Ghadimi, Kamel S. Saidi, Geraldine S. Cheok, Marek Franaszek, Robert R. Lipman

Abstract

This paper presents a new image-based approach for 3D mapping the locations of the rebar and embedded components in a railway bridge deck prior to placement of concrete. Our approach enables practitioners to quickly and automatically identify where the rebar and other underlying components are within the bridge decks, locate safe and unsafe drilling area, and creates a valuable documentation for future retrofit or rehabilitation of the concrete bridge decks. In the proposed method, digital images collected along the rebar cage prior to placement of concrete, are processed to automatically generate a 3D point cloud. Using a set of control points, the reconstructed point cloud is transformed into the site coordinate system. Next, a pattern recognition algorithm identifies the rebar locations. A cell-based map of the underlying structure is generated and the occupancies of the cells are automatically detected and visualized using a traffic light color spectrum. Impact of the number of images and control points on the accuracy and density of the image-based 3D reconstruction, registration, and automated recognition of the rebar locations and safe/unsafe cells are studied in detail. Results of our experiments show the promise on applicability of this low-cost approach in practice.
Proceedings Title
Proceedings of the 2012 Construction Research Congress
Conference Dates
May 21-23, 2012
Conference Location
West Lafayette, IN
Conference Title
Construction Research Congress 2012

Keywords

Railway, Rebar mapping, image-based 3D reconstruction, Concrete Placement

Citation

Golparvar-Fard, M. , Ghadimi, B. , Saidi, K. , Cheok, G. , Franaszek, M. and Lipman, R. (2012), Image-based 3D Mapping of Rebar Location for Automated Assessment of Safe Drilling Areas Prior to Placing Embedments in Concrete Bridge Decks, Proceedings of the 2012 Construction Research Congress, West Lafayette, IN, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=910289 (Accessed July 27, 2021)
Created May 23, 2012, Updated February 19, 2017