IN2TRACK3 - Research into optimized and future railway infrastructure Ground-based photogrammetry

Background

In Europe, railway infrastructure, including aging bridges, urgently requires maintenance and repair due to exceeding their intended lifespans. To assess bridge conditions, various inspection methods, both destructive and non-destructive, are used to identify issues like concrete deterioration, steel corrosion, and cracking. Traditional visual inspections are common for their low cost and speed but lack in detailed defect visualization and are subject to the inspectors' subjectivity, compromising reliability. Therefore, the demand for innovative, efficient, and reliable inspection techniques that minimize traffic disruptions is growing. Techniques such as Terrestrial Laser Scanning (TLS), Close-Range Photogrammetry (CRP), and Infrared Scanning (IS) offer non-contact, rapid data collection with high accuracy. Specifically, CRP has shown promise for cost-effective bridge inventory management, although its application remains limited. As part of IN2TRACK3, LTU has detailed the basic requirements for employing CRP in bridge inspections (weather conditions, equipment, and personnel expertise, for example).

Aim & Objectives

The aim of LTU’s task is to allow railway infrastructure owners to include ground based close range photogrammetry (CRP) as part of their bridge management system, reducing the possibility of errors associated to basic visual inspections and incrementing the amount of information available for each bridge.

The main objective is to develop step-by-step procedures to implement CRP as part of routine inspections of railway infrastructure, under different environmental conditions, equipment characteristics and personnel experience.

Results

The research performed in the use of CRP for survey of bridges demonstrated that its application in routine inspections of existing railway infrastructure can be advantageous for infrastructure managers. As part of this work, a detailed step-by-step methodology to perform such surveys was developed. Future efforts should focus on the implementation of the methodology by training personnel on the use of the equipment and collection of the photos, and subsequent surveys of bridges located along national road and rail lines.

In addition, the combination of CRP surveys, generation and updating of 3D models of the assets, and automated damage detection can provide key information to stakeholders and infrastructure managers. When these techniques are put together, it is possible to have a more precise insight regarding the damage evolution of a given structure, that can be easily neglected by traditional visual inspections based only on in situ visits. Although extensive research is being performed nowadays for the development and training of algorithms for image-based damage detection, they are still not easily available for infrastructure managers, surveyors, and bridge engineers.

Facts
Financer: TRV – EU H2020

Timeline: Project started in 01-21 and Project ended in 12-23.

Principal Investigator: Jaime Gonzalez-Libreros

Team members: Gabriel Sas, Thomas Blanksvärd, Chao Wang, Vedad Coric, Mert Pinar