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Number of results: 4
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Abstract

It is highly important to determine eigenvalues before and after certain extreme events that may cause damage accumulation, such as earthquake, blasts and mining or seismic tests on research models. Unique experiment design and shake table testing was performed to investigate seismic performance of a 3D RC building model with infill walls and advanced protection with polyurethane-based joints and fiber polymer reinforced light and emergency jackets. For the purpose of wider experimental activities, three methods for determination of the dynamic characteristics were used during multiple successive shake table tests following a dynamic pushover approach, and they are presented in detail. They are: inertance function through impact hammer tests, standard Fourier transformation of measured acceleration time history and digital image correlation. The expected differences in the results are related to the type and intensity of excitation used, the involvement of materials with different mechanical and physical properties, and with the different rate and extent of damage accumulation, as well as to local or global measurements. Y et, all methods lead to reliable results when a consistent methodology is being used, that takes into account locality or globality of measurements, leaving a choice for the most suitable one, depending on the site conditions. The inertance function method presented manifested its high efficiency in analysis of dynamic properties of large-scale structures and in monitoring of their changes caused by the damage and repair process. It offers quite a wide range of useful information, does not require very expensive equipment and its transportation cost is negligible. This method seems to be a proper diagnostic tool for simple experimental modal analysis of real structures and their structural elements, where detection of changes in the structural condition and in dynamic properties is required, also as a non-destructive testing and monitoring method. Digital image correlation proved to be a promising non-contact tool, strongly supporting the conventional instrumentation of shake table testing, while the Fourier transformation was used as a benchmark method yielding the most reliable results.
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Authors and Affiliations

Arkadiusz Kwiecień
1
ORCID: ORCID
Zoran Rakicevic
2
Jarosław Chełmecki
1
Aleksandra Bogdanovic
2
Marcin Tekieli
1
Łukasz Hojdys
1
Matija Gams
3
Piotr Krajewski
1
ORCID: ORCID
Filip Manojlovski
2
Antonio Soklarovski
2
Omer Faruk Halici
4
Theodoros Rousakis
Vachan Vanian
5

  1. Faculty of Civil Engineering, Cracow University of Technology, Cracow, Poland
  2. IZIIS, Ss. Cyril and Methodius University, Skopje, North Macedonia
  3. Faculty of Civil and Geodetic Engineering, University of Ljubljana, Ljubljana, Slovenia
  4. Istanbul Technical University, Istanbul, Turkey
  5. Democritus University of Thrace, Xanthi, Greece
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Abstract

In determining the effects of actions when designing road structures, the influence of the loads caused by the buffeting of the passing vehicles (high-cycle forces) is neglected. Taking into account the fatigue load, they can have a very large impact on the assessment of the load capacity. The subject of analysis is the pressure and velocity distributions around a truck. At the current stage of the work, it can be concluded that the gusts of passing trucks affect the dynamics of the gantry structure and the elements suspended on it, such as platforms or boards. There is a strong suction force. It is possible to simplify the model in such a way that the board and the wind move with the speed of the vehicle while the truck remains stationary. Due to the lack of reliable guidelines for strength calculations of such structures, advanced Computational Fluid Dynamics (CFD) tools were used. This paper also presents a shaking table built by the authors for dynamic loading of structural models. It describes the construction of the shaking table and the kind of movement made by the table deck. It also shows a scheme of the table deck suspension on linear bearings, as well as a scheme of the table motion system.
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Authors and Affiliations

Agnieszka Padewska-Jurczak
1
ORCID: ORCID
Dawid Cornik
1
ORCID: ORCID
Ryszard Walentynski
1
ORCID: ORCID
Maciej Wiśniowski
1
ORCID: ORCID
Piotr Szczepaniak
1
ORCID: ORCID

  1. Silesian University of Technology, Faculty of Civil Engineering, Department of Mechanics and Bridges, ul. Akademicka 5, 44-100 Gliwice, Poland
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Abstract

With the developing technology and increasing construction, the importance of structural observations, which are of great significance in disaster management, has increased. Geodetic methods have been preferred in recent years due to their high accuracy and ease of use in Structural Health Monitoring (SHM) Surveys. In this study, harmonic oscillation tests have been carried out on a shake table to determine the usability of the Single Base and the Network Real-Time Kinematic (RTK) Global Navigation Satellite Systems (GNSS) method in SHM studies. It is aimed to determine the harmonic movements of different amplitudes and frequencies created by the shake table with 20 Hz multi-GNSS equipment. The amplitude and frequency values of the movements created using Fast Fourier Transform (FFT) and Time Series Analysis have been calculated. The precision of the analysis results has been determined by comparing the LVDT (Linear Variable Differential Transformer) data, which is the position sensor of the shake table, with the GNSS data. The advantages of the two RTK methods over each other have been determined using the calculated amplitude and frequency differences. As a result of all experiments, it has been determined that network and single base RTK GNSS methods effectively monitor structural behaviours and natural frequencies.
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Authors and Affiliations

Güldane Oku Topal
1
ORCID: ORCID
Burak Akpinar
1
ORCID: ORCID

  1. Yildiz Technical Universty, Istanbul, Turkey
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Abstract

Advancements in technology and material sciences lead new solutions to be used in civil engineering. PolyUrethane Flexible Joints (PUFJ) and Fiber Reinforced PolyUrethanes (FRPU) are among those innovative solutions. PUFJ implemented systems comprise of seismic preventive buffer material between masonry infill walls and reinforced concrete (RC) frames, whereas FRPU solution is designed for covering the wall surfaces with thin composite strips. Both methods are primarily developed for increasing the ductility capacities of buildings while sustaining the overall structural strength without compromising on the safety of these systems against earthquakes. In this article, test results of the quasi-static cyclic experiments as well as dynamic tests on the shake tables including harmonic forces operating in resonance are presented. Moreover, numerical analyses are performed in order to comprehend the behavior of PUFJ implemented frames constituted with different masonry materials than above which are under various loading conditions. The outcomes confirmed the high efficiency of the proposed solutions, which at the same time meet the strict requirements of the modern seismic standards.
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Authors and Affiliations

Arkadiusz Kwiecień
1
ORCID: ORCID
Ahmet Tugrul Akyildiz
1

  1. Cracow University of Technology, Faculty of Civil Engineering, Warszawska 24,31-155 Cracow, Poland

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