International Society for Industrial Process Tomography

Detection of Steel Strand Cross Section Distribution in Post-Tensioned Pre-stressed Ducts Based on Simulation Studies

Nan Li ^1*, Mingchen Cao ², Cunfu He ³ and Bin Wu ³

¹ School of Automation, Northwestern Polytechnical University, Xi’an, Shaanxi 710071, China

² School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China

³ NDT&E Research Centre, Beijing University of Technology, Beijing, 100124, China

^*Email: nan.li@hotmail.co.uk

ABSTRACT

Post-tensioned pre-stressed duct has been widely used in the construction of bridges. The capacitive sensor has been successfully used in boundary detecting for post-tensioned pre-stressed ducts. In this paper, the capacitive sensing technique is applied to identify the cross section distribution of steel bar. An improved capacitive sensor structure is introduced for the identification. This contains four electrodes and each of them can be used as either exciting or receiving electrode. A series of models are built to simulate different positions of steel strand in post-tensioned pre-stressed duct. Two sets of measurements are described to detect the angle and center distance of steel strand. The simulated results are presented and analyzed for further identification. The processed results verify the effectiveness of the proposed sensor structure. The capacitive sensing technique shows potential for steel strand cross section distribution detection in post-tensioned pre-stressed ducts.

Keywords capacitive sensor, cross section distribution detection, post-tensioned pre-stressed duct.

Specific Industry SectorCivil engineering, pre-stressed bridge