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Experimental dynamic damage assessment of PUFJ protected brick infilled RC building during successive shake table tests

Kwiecień Arkadiusz, Rakicevic Zoran, Chełmecki Jarosław, Bogdanovic Aleksandra, Tekieli Marcin, Hojdys Łukasz, Gams Matija, Krajewski Piotr, Manojlovski Filip, Soklarovski Antonio, Halici Omer Faruk, Rousakis Theodoros, Vanian Vachan

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 3

art. no. e144940

EN

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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Earthquake protection of reinforced concrete structures with infill walls using PUFJ and FRPU systems

Kwiecień Arkadiusz, Akyildiz Ahmet Tugrul

Archives of Civil Engineering

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2023

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Vol. 69, nr 3

199--216

EN

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.

PL

Postępy w technologii i materiałoznawstwie prowadzą do nowych rozwiązań wprowadzanych w inżynierii lądowej. Wśród tych innowacyjnych rozwiązań znajdują się podatne złącza poliuretanowe (PUFJ) i poliuretany wzmocnione włóknami (FRPU). Systemy PUFJ instalowane są pomiędzy murowanymi ścianami wypełniającymi a ramami żelbetowymi jako anty-sejsmiczny element buforowy, natomiast systemy FRPU są przeznaczone do wzmacniania powierzchni ścian cienkimi pasami kompozytowymi. Obie metody zostały opracowane w celu zwiększenia ciągliwości budynków, przy jednoczesnym utrzymaniu ich ogólnej nośności, a tym samym w celu zwiększenia bezpieczeństwa użytkowania tych budynków w trakcie trzęsień ziemi. W artykule przedstawiono wyniki badań elementów w skali naturalnej pod quasi-statycznymi obciążeniami cyklicznymi oraz obciążeniami dynamicznymi na stole sejsmicznym i pod działaniem sił harmonicznych w rezonansie. Ponadto zostały przeprowadzone analizy numeryczne, mające na celu poznanie zachowania się podobnych konstrukcji z innymi materiałami murowymi współpracującymi z PUFJ, które poddane zostały różnym warunkom obciążenia. Wyniki potwierdziły wysoką skuteczność proponowanych rozwiązań, które jednocześnie spełniają surowe wymagania współczesnych norm sejsmicznych.

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The efficiency of single base and network RTK for Structural Health Monitoring

Topal Güldane Oku, Akpinar Burak

Advances in Geodesy and Geoinformation

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2022

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Vol. 71, no. 2

art. no. e28, 2022

EN

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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Static and dynamic response of cost effective unreinforced brick masonry buildings

Khan J. K., Abbas H.

Archives of Civil and Mechanical Engineering

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2011

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Vol. 11, no 4

921-941

EN

Besides the buildings with conventional one-brick thick solid masonry walls, two cost effective masonry wall constructions, viz. reduced thickness and cavity wall, have been studied for their lateral load resistance. The reduced thickness of wall was constructed with a combination of bricks on bed and bricks on edge; whereas the cavity wall was constructed with bricks on edge in Flemish bond using solid firedearth bricks. Single storey one-room building models were subjected to static lateral load and shake table tests. The study shows that there is considerable reduction in shear strength of buildings with cost effective masonry and the reduction is more than the saving in the material, which is due to increase in the vertical mortar joints in both masonry types. The base isolation system, using Teflon sheet, shows great promise for adoption in conventional as well as the cost effective building construction as a measure of earthquake safety.

PL

W uzupełnieniu do konwencjonalnych budynków o murowanej konstrukcji ścian z cegły w pracy zaprezentowano dwa typy budynków charakteryzujące się ekonomicznie efektywną konstrukcją ścian, uzyskaną poprzez: zmniejszenie ich grubości oraz zastosowanie pustki powietrznej. Jedno piętrowe modele budynków poddano analizie w zakresie statycznym pod względem odporności na obciążenie boczne oraz testowano ze względu na dynamiczne wymuszenia za pomocą stołu wzbudzającego. Wyniki badań wskazują, że istnieje znacząca redukcja w wytrzymałości na ścinanie budynków o zaproponowanej ekonomicznej konstrukcji murowanych ścian i jest ona bardziej znacząca niż oszczędności materiałowe, które wynikają ze wzrostu spoin pionowych w obu rozpatrywanych typach murów. Efektywność systemu izolacji podłoża przy pomocy przekładki teflonowej wskazuje na duże możliwości zaadoptowania go w budynkach tradycyjnych, jak i tych o ekonomicznej konstrukcji ścian, jako środek ich bezpieczeństwa w trzęsieniach ziemi.