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1

A review of soil-foundation-structure interaction and structure-soil-structure interaction effects based on numerical simulations

Nguyen Thang Ngoc, Ngo Van-Linh

Journal of Water and Land Development

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2025

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no. 66

1--12

EN

This study presents a comprehensive review of dynamic soil-foundation-structure interaction (SFSI) and structure-soil-structure interaction (SSSI) as addressed in modern seismic design codes and numerical simulation approaches. The investigation focuses on how SFSI and SSSI phenomena affect the vibrational response of structures under seismic loading. We employed a systematic methodology to select relevant literature and code provisions, analysing their treatment of interaction effects and comparing simulation results. Numerical studies, design standards, and experimental validations were considered to evaluate the implications of ignoring or incorporating interaction effects in structural design. Key findings indicate that while most codes provide procedures to account for SFSI, SSSI effects remain largely overlooked. Furthermore, current methods often assume linear soil behaviour, limiting their applicability to realworld conditions. Experimental results from centrifuge modelling and shaking table tests demonstrate that nonlinear soil behaviour and foundation flexibility can significantly alter seismic response. The SFSI has been found to reduce seismic demand through energy dissipation mechanisms such as rocking, while SSSI can either amplify or mitigate response depending on relative mass and stiffness. Despite these critical impacts, current design practices often neglect such interactions, particularly in densely built environments. These findings underline the necessity of integrating SFSI and SSSI into seismic analysis frameworks for safer and more accurate performance-based design. The review highlights the need for comprehensive models and experimental validation to support the development of more resilient design practices.

2

Mechanical Response of a Rectangular Reinforced Concrete Wall for a HighRise Building Basement Foundation under The Effect of an Earthquake

Nguyen Chi Thanh, Vu Ngoc Anh

Inżynieria Mineralna

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2025

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Vol. 1, no. 2

351--362

EN

With economic and societal development, high-rise buildings and their basement systems are receiving increasing attention in major cities worldwide. However, assessing the stability of high-rise basements during construction when subjected to seismic activity remains a crucial issue due to potential risks. This paper employs the Finite Element Method (FEM), using Plaxis2D software, to model a highrise basement foundation pit under construction, protected by reinforced concrete retaining walls under specific geological conditions. By applying a peak acceleration spectrum representative of a particular earthquake affecting the basement foundation pit, this study analyzes the earthquake's impact on the basement's stability. Based on the results, the paper provides commentary on the earthquake's effect on the stability of the high-rise basement foundation pit, and recommends measures to mitigate these effects.

3

Real-Time Building-Damage-Extraction Technology from Ground-Based Video Footage Using Normalized Difference Red/Green Redness Index

Shiraishi Haruhiro, Usuda Yuichiro

Geomatics and Environmental Engineering

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2025

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Vol. 19, no. 1

143--159

EN

When an earthquake occurs, promptly identifying the presence or absence of damage is crucial. This study developed a real-time building-damageextraction technique using ground-based imagery and evaluated its effectiveness. The technique applies the redness index (RI) (which was previously used in remote-sensing corrections for vegetation in arid regions) to identify “building damage” in those cases where buildings are partially or completely destroyed by earthquakes or tsunamis. To capture near-field and distant perspectives in the images, each image was divided into four quadrants (upper-left, upper-right, lower-left, and lowerright). The lower-left and lower-right quadrants were analyzed to assess the conditions on either side of a road in the near field using image recognition. Since the images contain latitudinal and longitudinal information, mapping the damage along the road can be automated by recording the route. Finally, a comparative analysis with other indices was conducted in order to evaluate RI’s superiority in damage mapping. The EMS-98 damage scale was used for damage assessment, classifying D5 (RI ≥ 0.08) as “building-collapse damage” and D0–D4 as “no building-collapse damage.” The average damage values for D5-classified buildings were significantly higher than others, thus demonstrating that RI provides practical and reliable results. Additionally, the study discussed comparisons with other indices and real-time evaluation methods. The authors sincerely hope this research contributes to life-saving efforts and deliveries of relief supplies in the aftermaths of earthquakes, ultimately saving many lives.

4

Application of continuous radon gas concentration telemonitoring for predictive seismic hazard assessment in Manado, Indonesia

Pratama Thomas Oka, Wijatna Agus Budhie, Sunarno, Sari Hermin Kartika, Yanti Ressy Jaya, Wijaya Rony, Waruwu Memory Motivanisman

Ecological Engineering & Environmental Technology

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2025

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Vol. 26, iss. 2

122--130

EN

Abnormal increases in radon gas (222Rn) concentrations in soil, groundwater, and atmosphere have been consistently observed as precursors of seismic activity, especially near active faults. In this study, we focus on earthquake prediction using IoT-based radon monitoring near the active fault in Manado, North Sulawesi, Indonesia, where seismic activity is high due to interactions between the Eurasian, Pacific, and Philippine plates. Radon gas concentration telemonitoring collected in real-time every minute between October 2023 and August 2024 was analyzed along with seismic data above M4.5 to predict earthquakes with magnitude 4.5 and above. This telemonitoring system enables continuous data storage every minute, with data accessible on the dataalamdiy web server, despite radon concentration readings on the detector updating every 10 minutes to filter out emissions from Thoron and Actanium sources.The results showed that earthquake date prediction sensitivity was 84%, accuracy was 75%, and the average prediction time was 2.65 days before the earthquake. The prediction was based on statistical algorithms derived from the daily average of radon gas concentration fluctuations, which resulted in an effective early warning system. One of the largest earthquakes M6.7 on January 9, 2024, was predicted 2 days ago. These findings highlight the possibility of integrating radon gas concentration anomaly analysis into disaster prevention strategies and provide an important lead time for preparedness efforts in seismically active areas. This research will significantly contribute to earthquake prediction methodology in Indonesia, especially in less-studied areas such as North Sulawesi, improving regional disaster preparedness and resilience.

5

Investigating the problems of historical buildings in relation to earthquakes and researching some of their retrofitting methods

Hassas Najmeh, Bordbar Amir Tabe

Budownictwo i Architektura

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2025

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Vol. 24, no 1

75--95

EN

Historical buildings are valuable cultural heritage sites that showcase diverse architectural typologies worldwide. However, these structures are highly susceptible to natural disasters, particularly earthquakes, which present unpredictable risks beyond human control. The primary objective of this research is to investigate the seismic behaviour of historical buildings and examine methods for their strengthening and preservation. This study analyses the seismic behaviour of various materials, including stone, brick, and mortar, in historical buildings and explores modern retrofitting methods, such as the use of nanotechnology and advanced material reinforcement. The findings indicate that employing advanced techniques can significantly enhance the seismic resistance of these structures. Finally, recommendations for future research and the application of innovative methods in the seismic retrofitting of historical buildings are provided. The study adopts an analytical-interpretive approach, emphasising minimal intervention and reversibility in preserving these invaluable structures.

PL

Budynki historyczne są cennymi miejscami dziedzictwa kulturowego, które prezentują różnorodne typologie architektoniczne na całym świecie. Jednak te struktury są bardzo podatne na klęski żywiołowe, w szczególności trzęsienia ziemi, które stwarzają nieprzewidywalne zagrożenia poza ludzką kontrolą. Głównym celem tych badań jest zbadanie zachowania sejsmicznego budynków historycznych i zbadanie metod ich wzmacniania i konserwacji. W tym badaniu analizuje się zachowanie sejsmiczne różnych materiałów, w tym kamienia, cegły i zaprawy, w budynkach historycznych i bada nowoczesne metody modernizacji, takie jak wykorzystanie nanotechnologii i zaawansowanego wzmocnienia materiałowego. Wyniki wskazują, że zastosowanie zaawansowanych technik może znacznie zwiększyć odporność sejsmiczną tych struktur. Na koniec przedstawiono zalecenia dotyczące przyszłych badań i zastosowania innowacyjnych metod w modernizacji sejsmicznej budynków historycznych. W badaniu przyjęto podejście analityczno-interpretacyjne, podkreślając minimalną interwencję i odwracalność w zachowaniu tych bezcennych struktur.

6

Effect of Shear Walls Length on the Behavior of Reinforced Concrete Structures

Rafa Sid Ali, Rouaz Idriss, Brahim Mounia Hadj, Ghribi Zakaria

Inżynieria Mineralna

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2024

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Vol. 1, no. 2

art. no. 02

EN

On May 21, 2003, a powerful earthquake with a moment magnitude of Mw=6.8 struck the city of Boumerdes, which is located roughly 50 km east of Algiers, the capital city of Algeria. 2,278 people lost their lives as a result of the earthquake, which also caused several buildings and infrastructures to collapse. Structures with reinforced concrete (R/C) frames did not withstand the earthquake, according to post-seismic observations. In order to reduce risks related to this type of construction, the revised version of the Algerian Seismic Code (RPA 99 Version 2003) restricted the use of RC frame structures to two-story buildings or structures that were eight meters or taller. Over this threshold, shear walls must either fully or partially resist the earthquake loads. To comply with this new requirement, engineers adopted a new construction system by using small length shear walls arranged in Lshape at the corners of the building. In order to assess the efficiency of this shear walls configuration, a series of numerical analysis has been performed using the finite element method where the shear walls length was varied from 0.60 m to 2.00 m. For the purpose of this study a typical three-story building constructed in Algeria's most seismically active region, Algiers and the surrounding area, has been selected for this investigation.

7

Seismic Behavior and Stability Analysis of an Embankment Dam on a Permeable Foundation

Dihman Sanchit, Chaturvedy Gyanendra Kumar, Pandey Umesh Kumar, Bhandari Sanjay

Civil and Environmental Engineering Reports

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2024

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Vol. 34, no. 2

117--140

EN

This study analyses the behaviour of an embankment type homogenous earth dam with a plastic clay core subjected to an earthquake excitation and its deformation with time. The displacement vs time graph has been plotted under the earthquake excitation and deformation for the structure is found out. The analysis tries to depict the real-life performance of the dam under earthquake excitations for its additional safety consideration. GeoStudio has been used to perform the QUAKE/W analysis on the dam. QUAKE/W models the dynamic stresses arising from earthquake shaking and simulates the impact of these stresses on the earth’s structures. The software is based on the finite element method. The study also consists of seepage analysis of the dam body with impervious clay core and generation of the zero-pressure line along with the flow lines and generation of flow vectors within the body of the dam. The SEEP/W analysis has been used for the generation of the seepage across the dam body which may be further used to check the stability of the dam. In addition to that, a slope stability analysis has also been performed using SLOPE/W analysis to get the desired value of the factor of safety.

8

Experimental investigation of RC shear walls with openings under cyclic loading repaired with externally bonded CFRP strips

Ozdemir Anil, Kopraman Yagmur

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 1

art. no. e14, 2024

EN

A total of 9 real scale reinforced concrete shear walls were produced, 3 of them being the reference, representing the basement floor of a reinforced concrete building. These 9 shear walls produced, 3 wall are fully filled, 3 of them have window openings and 3 of them have door openings. The RC shear walls were exposed to displacement-controlled reversed cyclic lateral loading. In the experiments that damaged the experimental specimens, loads up to 0.5% story drift ratio for moderate damage and 1.0% story drift ratio for heavy damage were applied. Within the scope of the experimental study, the damage distributions of the tested nine RC shear walls were examined in detail, and the strengthening technique was developed using CFRP strip and CFRP fan-type anchors. The performance of damaged RC shear walls after using the devised repair method was analysed. The study's findings revealed that the repair method created by employing CFRP strips to restore moderately damaged RC shear walls with and without apertures was well enough successful in restoring the shear walls' performance levels.

9

Hospital Patient Distribution After Earthquake

Fidanova Stefka, Kirilov Leoneed, Ivanov Veselin, Ganzha Maria

Annals of Computer Science and Information Systems

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2024

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Vol. 39

597--601

EN

The correct organization of medical assistance after the occurrence of a major disaster is very important for saving the lives of the victims. Earthquakes are natural phenomena/disasters in which there are many victims. The timely provision of medical assistance to the injured is an important element of their service. It is good to divide them into types of injuries and severity of injuries. Thus, the medical teams will be prepared for how many people need outpatient treatment and how many need hospital treatment. Rapid distribution of victims to hospitals according to their injuries can reduce the number of deaths and people with serious consequences. In this article, we present a breakdown of the injured by hospitals and medical facilities near the earthquake site. The type of injuries and the capacity and equipment of hospital facilities are taken into account.

10

The 2 December 2020 MW 4.6, Kallithea (Viotia), central Greece earthquake: a very shallow damaging rupture detected by InSAR and its role in strain accommodation by neotectonic normal faults

Valkaniotis Sotiris, De Novellis Vincenzo, Ganas Athanassios, Sansosti Eugenio, Convertito Vincenzo, Briole Pierre, Tsironi Varvara, Karasante Ilektra, Karamitros Ioannis

Acta Geophysica

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2024

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Vol. 72, no. 3

1523--1541

EN

On 2 December 2020 10:54 UTC a shallow earthquake of MW (NOA) = 4.6 occurred near the village of Kallithea (to the east of Thiva), central Greece, which, despite its modest size, was locally damaging. Using InSAR and GNSS data, we mapped a permanent change on the ground surface, i.e., a subsidence of 7 cm. Our geodetic inversion modelling indicates that the rupture occurred on a WNW-ESE striking, SSW-dipping normal fault, with a dip-angle of ~ 54°. The maximum slip value was 0.35 m, which was reached at a depth of about 1100 m. The analysis of broadband seismological data also provided kinematic source parameters such as moment magnitude MW = 4.6 (± 0.1), rupture area 6.3 km2 and mean slip 0.16 m, which agree with the values obtained from the geodetic model. The effects of the earthquake were disproportionate to its moderate magnitude, probably due to its unusually shallow depth (slip centroid at 1.1 km) and the high efficiency of the earthquake (radiation efficiency q = 0.62). The geodetic data inversion also indicates that within the uncertainty limits of the technique, three scenarios are possible (a) the earthquake responsible for the mapped surface deformation may have occurred on a ~ 2-km long, blind normal fault different from the well-known active Kallithea normal fault or (b) could have occurred along a secondary fault that branches off the Kallithea fault or (c) it may have occurred along the Kallithea fault itself, but with its geometrical configuration could not be modelled with available data. We have also concluded that with a high dip-angle Kallithea Fault forward model it is not possible to fit the geodetic data. The rupture initiated at a very shallow depth (1.1 km) and it could not propagate deeper possibly because of a structural barrier down-dip. The 2020 event near Kallithea highlighted the structural complexity in this region of the Asopos Rift valley as the reactivation of the WNW-ESE structures indicates their significant role in strain accommodation and that they still represent a seismic hazard for this region.

11

Geophysical investigation on the subsoil characteristics of the Dendam Tak Sudah Lake site in Bengkulu City, Indonesia

Mase Lindung Zalbuin, Amri Khairul, Ueda Kyohei, Apriani Rita, Utami Fazriati, Tobita Tetsuo, Likitlersuang Suched

Acta Geophysica

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2024

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Vol. 72, no. 2

893--913

EN

Bengkulu City in Indonesia is one of the areas prone to earthquakes, yet it has developed increasingly in the last five years. One of the prospective areas in Bengkulu City, called Singaran Pati, is located close to the Dendam Tak Sudah Lake, a natural tropical lake. This research aims to interpret geological characteristics for the spatial plan development in the study area. Microtremor measurement and site investigation are implemented to observe the geophysical and geological characteristics of the study site. Inversion analysis using Monte Carlo simulated annealing is conducted to generate a shear wave velocity profile. Based on the shear wave velocity, the identified bedrock surface is illustrated in a 3D geological model. A simple analysis of the natural period to estimate allowable structural building storeys is also performed. Results show that the depth of the bedrock surface is around 4.5-147 m. The study area is dominantly categorised as Site Classes C and D. Low- to medium-rise buildings are appropriate to construct based on the geophysical and geotechnical information. The findings can provide preliminary guidelines on geotechnical and geological information for the seismic site conditions in the study area in Bengkulu City.

12

Study on safety management in Turkish earthquakes

Stasiak-Betlejewska Renata, Ömek Gökhan

System Safety : Human - Technical Facility - Environment

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2023

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Vol. 5, iss. 1

224--230

EN

Natural disasters affect not only humans but also all living beings and societal elements. The term "disaster “meaning a Great Calamity. Among these calamities, earthquakes stand out as the most significant in terms of the damages they cause. Internationally, all authorities define earthquakes as the disasters that result in the highest loss of life and property. This paper highlights the urgent need for effective debris management measures, drawing on established scientific knowledge and operational experience from scientific studies authored by universities. By highlighting the challenges faced during earthquake debris management and safety management and the associated threats to public health and the environment, this study was undertaken to raise people's awareness against similar negligence in future catastrophic events.

13

Trzęsienie ziemi w Maroku

Wojnarowicz Michel

Inżynieria Morska i Geotechnika

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2023

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nr 5

217--221

PL

Informacja o tragicznym trzęsieniu ziemi o magnitudzie 6,8 w skali Richtera, do jakiego doszło we wrześniu 2023 roku w Maroku, w prowincji Al Haouz. Przyczyny i skutki trzęsienia ziemi w Maroku. Wytyczne Eurokodu 8 dotyczące klasyfikacji stref zagrożonych trzęsieniem ziemi oraz klas podłoża gruntowego i kategorii podatności budynków pod względem ryzyka sejsmicznego. Zalecenia konstrukcyjne budynków zwiększające bezpieczeństwo podczas trzęsień ziemi.

EN

Information about the tragic earthquake with a magnitude of 6.8 on the Richter scale that occurred in September 2023 in Morocco, in the Al Haouz province. Causes and effects of the earthquake in Morocco. Eurocode 8 guidelines for the classification of earthquake hazard zones and subsoil classes and building vulnerability categories in terms of seismic risk. Building design recommendations to increase earthquake safety.

14

Wstrząs w ogóle i szczególe

Królikowski Jerzy

Geodeta : magazyn geoinformacyjny

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2023

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nr 3

8--9

15

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.

16

Seismic performance evaluation of a base-isolated steel liquid storage tank with limiting-devices considering soil-structure interaction

Jing Wei, Tian Shuang

Archives of Civil Engineering

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2023

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Vol. 69, nr 4

635--661

EN

Liquid storage tank is widely used in the petrochemical industry, earthquake will lead to structural damage and secondary disasters, and damping control opens up a new way for seismic design of liquid storage tank. Considering soil-structure-fluid interaction, liquid sloshing dynamic behavior and material nonlinearity, a three-dimensional calculation model of shock absorption liquid storage tank is established by combining sliding isolation and displacement-limiting devices. The dynamic responses of the liquid storage tanks under the action of Kobe and El-Centro waves are investigated, and the influence of soil-structure interaction (SSI) on the dynamic response is discussed. The results show that the damping ratio is basically between 30% and 90%. After the SSI is considered, the damping ratio of liquid sloshing wave height is increased, while the damping ratio of the dynamic response of the liquid storage tank is decreased, and the change of elastic modulus has little effect on the damping effect. The sliding isolation with displacement-limiting devices has significant damping control effects on the liquid sloshing wave height and the dynamic responses of the liquid storage tank.

17

Research on the dynamics of lightweight shell and spatial structures with the aid of computational fluid dynamics and a shaking table

Padewska-Jurczak Agnieszka, Cornik Dawid, Walentyński Ryszard, Wiśniowski Maciej, Szczepaniak Piotr

Archives of Civil Engineering

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2023

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Vol. 69, nr 4

379--392

EN

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.

PL

Przy określaniu skutków oddziaływań przy projektowaniu obiektów drogowych pomija się wpływ obciążeń wywołanych podmuchami od przejeżdżających pojazdów (siły wysokocyklowe). Biorąc pod uwagę również obciążenie zmęczeniowe, mogą one mieć bardzo duży wpływ na ocenę nośności konstrukcji. Przedmiotem analizy są rozkłady ciśnień i prędkości wokół samochodu ciężarowego. Na obecnym etapie prac można stwierdzić, że podmuchy od przejeżdżających ciężarówek wpływają na dynamikę konstrukcji bramownicy i zawieszonych na niej elementów, takich jak pomosty czy tablice. Istnieje duża siła ssąca. Możliwe jest uproszczenie modelu w taki sposób, aby tablica i wiatr poruszały się z prędkością pojazdu, podczas gdy ciężarówka pozostaje nieruchoma. Ze względu na brak rzetelnych wytycznych do obliczeń wytrzymałościowych takich konstrukcji, zastosowano zaawansowane narzędzia obliczeniowej mechaniki płynów (CFD). W artykule przedstawiono również zbudowany przez autorów stół wstrząsowy do dynamicznego obciążania modeli konstrukcyjnych. Opisano w nim konstrukcję stołu oraz rodzaj ruchu, jaki wykonuje płyta stołu. Przedstawiono również schemat zawieszenia płyty stołu na liniowych łożyskach oraz schemat układu ruchu stołu.

18

Simulation of strong ground motions of 1991 Uttarkashi (M 7) and 1999 Chamoli (M 6.6) earthquakes using modified hybrid technique

Sharma Anjali, Kumar Dinesh, Paul Ajay, Teotia Satybir Singh

Acta Geophysica

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2023

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Vol. 71, no. 6

2573--2602

EN

In the present study, 1991 Uttarkashi (M 7) and 1999 Chamoli (M 6.6) earthquakes that occurred on October 19, 1991, at 21:23:14 h and March 28, 1999, at 19:05:11 h, respectively, have been simulated using the modified hybrid technique. Hybrid technique is the combination of two existing techniques, i.e., envelope technique and composite source model technique. In the present modified technique, site amplification functions and kappa factor have also been incorporated. The simulated waveforms and their corresponding response and Fourier spectra for each site have been generated. In this study, simulation has been done at 11 and 9 recorded stations of Uttarkashi and Chamoli earthquakes, respectively. Important frequency - and time-domain parameters, i.e., Fourier spectra, response spectra, peak ground acceleration (PGA) and duration at stations, have been estimated and compared with the observed accelerograms. It has been observed that the simulated PGA (231 cm/s2) at the closest distance Bhatwari (22 km) matched with the observed one (248 cm/s2) for the Uttarkashi earthquake. The same has been observed at the nearest most station Gopeshwar (19 km) of the Chamoli earthquake. The simulated PGA (347 cm/s2) for this station has been found well matched with the observed PGA value (352 cm/s2). Similar matching has been observed for other stations also. The present technique is independent of velocity-Q structure of earth’s layered model and past events data of small earthquakes. This study brings light on the site effect and high-frequency decay parameter. This study can be very helpful in the estimation of seismic hazard in a specific region and designing earthquake-resistant buildings.

19

Seismo ionospheric anomalies related to the Mw 7.5, Kepulauan Alor, Indonesia earthquake

Koklu Kevser

Acta Geophysica

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2023

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Vol. 71, no. 6

2633--2644

EN

Discussions about anomaly in the ionosphere have made significant progress since the great Alaskan earthquake, in 1964. Specifying signs of precursors of an earthquake and traces of the aftershock of its may minimize every kind losses. This study examines the possible effect on the ionosphere of the M7.5 earthquake that occurred at 21:46 UT on November 11, 2004, near Kepulauan, Alor Islands (8,152°S-124,868°E), Indonesia. This effect is observed in TEC (TECU) data. The limits of the TEC data gained from IRI-2016 are determined by the statistical method. Anomalies are marked by means of out-of-bounds data. Anomaly causes are introduced to the reader according to the principle of causality. In this context, a portrait of space climate conditions is drawn with the aid of the earthquake, geomagnetic storm, and solar activity effect. According to this portrait, we perceive on October 15, November 10, and December 1-11. Probably the November 10 anomaly is caused by the earthquake and the other anomaly days may be related to the aftershock of the earthquake.

20

Ionospheric perturbations: a case study of 2007 five major earthquakes using DEMETER data

Thomas Jewel Emem, Ekanem Aniekan Martin, George Nyakno Jimmy, Akpan Anthony Effiong

Acta Geophysica

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2023

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Vol. 71, no. 4

1607--1618

EN

Using the Plasma analyzer (IAP) and Langmuir Probe (ISL) experiments of the Detection of Electromagnetic Emissions Transmitted from Earthquake Regions (DEMETER) lithospheric–atmospheric–ionospheric coupling has been observed before, during and after five major earthquakes with magnitudes greater than 6.5. The aim of this study is to use ionospheric parameters to identify the ionospheric perturbations associated with the five earthquake regions screened. All the three investigated ionospheric parameters of electron density, electron temperature and total ion density recorded perturbations within the investigative period. A total of 36 anomalies were obtained with 18 each for nighttime and daytime readings. The observed anomalies being screened for false alarm using the geomagnetic indices of Kernnifzer digit (kp) and disturbance storm time (Dst.) revealed 27.8% as geomagnetically induced perturbations. Thus, 72.2% of the studied anomalies transpired in quiet geomagnetic conditions, which is linked to seismic events.