Case Studies
CASE STUDY 1
Amir S.
Researcher, Norway
Our group is working as the leader of work package 5 of the HYPERION project. HYPERION is a 4-year EC Funded project that has received funding from the European Union’s Horizon 2020 research and innovation program. The main focus of the project is to assess the vulnerability of the historic area subjected to different types of risks and investigate their impact on economies, politics, and societies to deliver an integrated resilience assessment platform. In the link below, you can find more about the project: https://www.hyperion-project.eu/
Since destructive tests for investigating the material properties of cultural heritage assets is impossible, nondestructive solutions should be utilized. For this purpose, the operational modal analysis is employed for model updating the assets to provide a robust finite element model.
Since destructive tests for investigating the material properties of cultural heritage assets is impossible, nondestructive solutions should be utilized. For this purpose, the operational modal analysis is employed for model updating the assets to provide a robust finite element model.
Installation of the sensors is effortless and does not any special equipment, and it can be done with glue and steel plates as the sensors’ bases. Moreover, the Unquake software is friendly to perform the initial analysis to have an overview of the test in the most efficient way.
The first customers are always the losers! We also expect problems with the sensors and bugs for the software, and we also face these problems. But if I want to be honest, we could not feel them due to the best customer service of the company. I really appreciate all the supports and helps that we had during our project from the company employees. They were on time for answering the questions and helpful for solving the problems, and we could reach them even by phone easily during the day.
CASE STUDY 2
ARIS X
Structural Engineer, Greece
The accelerographs were used for the operation modal analysis of the following projects:
- A-Structural Assessment and Restoration of an early 20th century three-span stone bridge, named the Bridge of Sima. The bridge is located on the regional road network of the Municipality of Rethymno, Crete, Greece.
- B-Structural Assessment and Rehabilitation of the City Hall of Rethymno, Crete, Greece. The building ‘s structural system is made of reinforced concrete.
- C-Structural Assessment and Restoration of the 19th century stone Lighthouse of the Venetian Harbour in the Old Town of Rethymno Crete, Greece.
For projects A and C the solution of Operation Modal Analysis was selected because it is considered as, probably, the only reliable method for extracting the dynamic characteristics of a masonry structure. Destructive and medium destructive technics like core sampling and rebound test, give an evaluation of the mechanical properties of masonry ‘s stone and mortar. But the behavior of masonry as a homogenous material cannot be extracted. Therefore, the Operational Modal Analysis gave an approximation of the real vibration frequencies of the structure. Those data were used for the calibration of a finite element model created, comparing calculated and measured frequencies.Regarding project B, although the concrete ‘s characteristics are more easily to be estimated, the Operational Modal Analysis made possible to evaluate all the factors that influence the dynamic response of the building, such as the influence of the infill masonry. Although concrete acts as a homogenous material, much more comparing to masonry, it was observed a wide variation of the finite element model frequencies compared to the measured ones. That proved the necessity of reliable estimation of the dynamic behavior, even in the cases of more “common” structural systems.
There was a concern regarding the sensitivity of the acceleographs. Meaning whether they would be able to isolate the dominant frequencies, in case of vibration form factors, other than ambient viabration. Nevertheless, even in the case of the stone bridge, the acceleographs were able to distinguish the ambient vibration from the external factors (car traffic vibrations)
It was surprisingly easy to install the sensors and process the data even in the case of multiple accelerographs installation.
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