Inspire : Public Works July Aug 2013
28 Public Works Professional July-August 2013 TRACKING THE CRACKS WITH 3D TECHNOLOGY Assessing the condition of road networks was once a tedious eyeballing exercise. Now, 3D technology is boosting the speed and accuracy of pavement profling. This new system is a typical example. PROTECTING PAVEMENTS The road network is a local government agency's most valuable asset, but maintaining it in the best possible condition can be a challenge, especially in this era of limited funding. That's why many a council relies on a pavement management system (PMS) to develop a works program that won't dent its maintenance budget. But for that to succeed, it's imperative to measure the road network's condition on a regular basis, because PMS decisions are based on that information. In the past, much of the pavement condition data that was critical to a PMS (such as surface distress) was assessed visually -- either on foot, from the window of a slow moving van or by reviewing video data of the road surface. However, that slow and subjective analysis didn't always ensure 100% coverage of the entire road network. NEW ENHANCED METHOD The recent integration of automated 3D technology into road survey platforms like the ARRB Network Survey Vehicle [pictured] has markedly enhanced the method of collecting data to better maintain road networks The two 3D sensor units at the rear of the vehicle project a laser line onto the road surface, while a camera inside each of them accurately measures a two-metre pro le of more than 2000 measurement points across the road surface. Together, the two cameras can measure a 4m-wide transverse pro le. The system takes one measurement every 5mm or less, and by combining the contiguous transverse pro les, a 3D model of the road surface is generated. This information is then used to automatically identify a variety of pavement surface defects, such as cracking (which is probably the most critical) as well as ravelling, delamination and potholes. EASY TO SPOT Three-dimensional images of a road surface are generated with the cracks automatically identi ed and colour coding used to classify widths. Pink lines either side of the image indicate the location of the re ective lane markings as detected by the 3D sensor. These can then be used to set the boundaries within which the cracking is identi ed. The ARRB Automatic Crack Detection System operates at prevailing tra c speeds and can collect a range of data, including that of rutting and texture, across a network in a safe and economic manner. When combined with other systems like laser pro lers, digital asset cameras and GPS, most pavement condition parameters required by a PMS can be accurately measured and recorded in a single survey operation. While 3D technology is relatively new, it is tipped to become a widely used tool for monitoring and maintaining road networks for local government agencies. A technical paper explaining more attributes of this new technology will be presented at the forthcoming IPWEA International Conference in Darwin by Richard Wix, ARRB Group's Principal Engineer, Systems. ••• 3D image of road surface, with cracks highlighted. An ARRB Network Survey Vehicle with Auto Crack Detection system.
Public Works May Jun 2013
Public Works Professional Sept - Oct 2013