Monitoring deformations and movements of structures is an essential tool for asset management and condition monitoring.
NTU's civil engineering students use mechanical and electronic devices to collect response measurements, including strains and displacements of laboratory structures. Displacements and deformations are measured using contact sensors such as strain gauges and mechanical dial indicators. Technical support is required to install these measurement devices. There is often the need for manual note-taking during the experiment, which can provide unreliable measurements.
Through Dr Rolands Kromanis’s research in technological applications to understand behaviour of structures, he has developed a low cost vision-based deformation monitoring system – called DeForMonit. DeForMonit replaces this antiquated measurement collection apparatus with a vision-based, contactless technology solution that uses mobile phone camera technology.
There are software solutions currently on the market that perform in the same way as DeForMonit but these operate using specialised high-resolution cameras and software licences that can cost in excess of £20,000 a year. Dr Kromanis has conducted extensive research to find a more cost-effective and accessible solution.
Addressing the Challenge
Smartphones have become the hub of our daily lives with the majority of university students owning or having access to one. The camera function on a smartphone can be used to capture images (stream video) of a test-bed subjected to loading and identify the changes in the structures’ response. The camera is used to monitor specific markers on a structure.
From the images, information can be extracted which relates to the changes of the structure such as deformations and crack propagation (in concrete structures). It provides accurate measurements of vertical displacements and strains in laboratory structures. Students use their phone cameras to capture deformations and then use an app to extract deformations and cracks from captured images/streamed videos.
Dr Kromanis has received BEng (Hons) in Civil and Structural Engineering (University of Bradford), MSc in Structural Engineering (University of Dundee) and PhD in Civil Engineering with Computer Sciences (University of Exeter).
He joined NTU’s Civil Engineering Section in the School of Architecture, Design and the Built Environment in September 2015. His research focuses on the structural performance evaluation of bridges using measurements from continuous monitoring.
Roland is interested in applications of technologies to understand behaviour of structures. For example, complimenting a structure with a sensory network, which mimics a ‘nervous system’ in human bodies, enables collections of information related to inputs to and outputs from the system. Then the understanding of interactions between physical and digital worlds using appropriate interpretation tools can be made possible, hence broadening our knowledge of ways things and we work. The main challenge in all this is to make sense of collected measurements.
DeforMonit - Image Processing Freeware
DeforMonit can be used to replace conventional displacement sensors/strain gauges, reduce workload of technicians, promote collaborative work between students, capture deformations of the entire laboratory test-bed and has potential real-life applications to full-scale structures. The technology is simple, low-cost and provides indicative and time accurate information about structural response. It is currently used to support teaching on MSc Structural Engineering and Materials and student projects.
Publications and PR
- Kromanis, R. and Liang, H., (2018) Condition assessment of structures using smartphones: a position independent multi-epoch imaging approach. In: 9th European Workshop on Structural Health Monitoring Series (EWSHM), Manchester Hilton, Manchester, 10-13 July 2018 (https://www.ndt.net/search/docs.php3?showForm=off&id=23271)
- Kromanis R (March 22, 2018) Cheap, available technologies could make monitoring bridges easier and prevent tragedies like the one in Florida. The Conversation, Science + Technology Section. (https://theconversation.com/cheap-available-technologies-could-make-monitoring-bridges-easier-and-prevent-tragedies-like-the-one-in-florida-93535)
- Kromanis R.(2018) Estimating Deformations of Laboratory Structures Subjected to Loadings Using Images Collected with Phone Cameras. Trends in Civil Engineering & Material Sciences 1(3). (http://www.lupinepublishers.com/tceia/pdf/TCEIA.MS.ID.000111.pdf)
- Kromanis R and Al-Habaibeh A. (2017) Low cost vision-based systems using smartphones for measuring deformations in structures for condition assessment. International Conference on Structural Health Monitoring of Intelligent Infrastructure (SHMII-8), Brisbane, Australia, 5th – 8th Dec 2017. (https://www.researchgate.net/publication/323028607_Low_cost_vision-based_systems_using_smartphones_for_measuring_deformation_in_structures_for_condition_monitoring_and_asset_management)