Institute of Earthquake Engineering and Engineering Seismology

Permanent URI for this communityhttps://repository.ukim.mk/handle/20.500.12188/26

Browse

Search Results

Now showing 1 - 10 of 16

Some of the metrics are blocked by your
consent settings
Experimental Verification of Innovative, Low-Cost Method for Upgrading of Seismic Resistance of Masonry Infilled Rc Frames
(MDPI AG, 2025-07-31)
Bojadjiev, Jordan
;
;
Necevska Cvetanovska, Golubka
;
Varevac, Damir
;
Bojadjieva, Julijana
<jats:p>For the past few decades, during each disastrous earthquake, severe damage and poor seismic performance of masonry infilled RC frames, including many newly designed ones, have been reported extensively. Inherent problems related to analysis and design methods for tight-fit infilled frame structures have not yet been solved and are recognized as being far from satisfactory in terms of completeness and reliability. The primary objective of this research was to propose and test an innovative method that can effectively mitigate undesirable interaction damage to masonry infilled RC frame structures. This proposed technical solution consists of connection of the infill panel to the bounding columns with steel reinforcement connections deployed in mortar layers and anchored to the columns. This is practical, cheap and easy to implement without any specific technology, which is especially important for developing countries. A three story, two bay RC building model with the proposed connection implemented on the infill walls was designed and tested on the shake table at IZIIS in Skopje, N. Macedonia. The test results and design guidelines/recommendations from the proposed research are also expected to benefit the infrastructural development in other countries threatened by earthquakes, preferably in the Balkan and the Mediterranean region.</jats:p>
Some of the metrics are blocked by your
consent settings
Kinematic SSI effects on seismic performance of RC structures
(Croatian Association of Civil Engineers, 2024-09)
Petrov, Nikola
;
Bojadjieva, Julijana
;
Bojadjiev, Jordan
<jats:p>In seismic regions, understanding soil–structure interaction (SSI) is crucial. This study examines the SSI effects on a six-storey RC-frame building using American guidelines for soil types B and C as per Eurocode 8. Structural responses of a constant structural system under various soil types and embedment conditions are compared, revealing significant influences on seismic behaviour. The study employs linear-elastic analysis to demonstrate that local soil and embedment conditions decrease base shear forces but increase total horizontal displacements and inter-storey drifts. This study highlights the importance of considering local soil conditions and embedment configurations to ensure structural resilience in earthquake-prone areas.</jats:p>
Some of the metrics are blocked by your
consent settings
Решенија за ограничување од облогата и хидродинамичка стабилност на јаловишна брана
(Сплит- ХрватскФакултет за Градежништво Архитектура и Геодезија; Матице Хрватске 15, HR-21000 Сплит, 2023-12-12)
Mircevska Violeta
The study investigates the impact of reservoir lining on the hydrodynamic stability of a tailings dam. A 3D coupled fluid-solid finite element model was used for detailed seepage analyses based on conventional flow-net and steady seepage conditions. Pore pressure, stationary seepage velocities, static liquefaction and the ratio between manifested and critical hydraulic gradients were predicted under three different lining conditions. The highest potential for internal erosion and heave was observed in the lined reservoir and starter dam scenario. Although there are environmental benefits, the incorporation of liners in dam design requires a comprehensive engineering assessment of the negative hydrodynamic effects.
Some of the metrics are blocked by your
consent settings
ПРОЦЕНА НА СЕИЗМИЧКИ РИЗИК КАКО ОСНОВА ЗА ОДРЖЛИВ УРБАН РАЗВОЈ
(UKIM-IZIIS, 2023-12-14)
Kefajet Edip
Современото урбанистичко планирање се стреми кон постигнување на целите на одржлив развој меѓу кои клучно е намалувањето на ризиците од природните катастрофи. Но истовремено, урбанистичкото планирање се наоѓа под притисок на брзата урбанизација што го отежнува имплементирањето на принципите на одржлив развој. Постојат голем број на населени места развиени во територии каде постои опасност од еден или повеќе видови на природни хазарди. Земјотресот се смета за еден од најдеструктивните, особено за урбаните средини кои имаат висока повредливост и голема густина на населеност. Предмет на истражување во докторскиот труд е процена на сеизмичкиот ризик во урбани средини како основа за одржлив урбан развој. Сеизмичката сигурност на изградената животна средина се базира на објекти проектирани и изградени согласно важечките сеизмички прописи. Но, урбаната структура на градовите се состои и од објекти изградени во различни периоди, пред и после воведување на сеизмичките прописи и истата е динамична како резултат на различни реконструкции и адаптации. Градбите изградени пред воведување на сеизмичките прописи имаат непознат степен на сеизмичка сигурност а со тоа ги прават урбаните средини повредливи на сеизмички ризик. Во рамки на докторатот, исто така е направена воведна анализа на постојната улога на урбанистичкото планирање во намалување на сеизмичкиот ризик низ преглед на праксата на урбанистичко планирање во неколку земји развиени во сеизмички активни региони. Со цел утврдување на нивото на сеизмички ризик и идентификување на урбанистичките параметри кои влијаат на сеизмичкиот ризик, како пилот студија е избрана урбана единица во оштина Карпош во Скопје, територија со релативно висока сеизмичност. Модерниот изглед на Градот Скопје започнал да се гради после земјотресот од 1963 година кој претставува најголема природна катастрофа во историјата на градот. За да се направи процена на сеизмички ризик на пилот студијата најпрво се дефинирани компонентите на ризик: хазард, изложеност и повредливост. Сеизмичкиот хазард е дефиниран со детерминистички и веројатносен пристап. Податоците за сеизмички хазард се превземени од базата на податоци на ESHM20 (Danciu et al., 2021). При детерминистичкиот пристап се дефинирани две земјотресни сценарија, земјотрес со Mw 6.6 на 10км и земјотрес со Mw 7.1 на 100км радиус од пилот студијата. Во веројатностниот пристап, интензитетот на движење на тлото е одреден за повратни периоди од 95 и 475 години. Локалните почвени услови се дефинирани согласно претходна студија направена од страна на ИЗИИС (Дојчиновски и сораб., 2013) и податоци од регионални почвени услови дефинирани во ESRM20 (Crowley et al., 2021). Компонентата изложеност е дефинирана според две урбанистички сценарија, постојна (сценарио 1) и планирана состојба (сценарио 2). Постојната состојба на градежниот фонд се базира на претходни студии на ИЗИИС (Нечевска-Цветановска и сораб., 2013; Apostolska et al., 2018), додека планираната состојба е дефинирана согласно ДУП (Тајфа план, 2015).
Some of the metrics are blocked by your
consent settings
Influence of railway induced vibrations on structures and humans in urban areas
(Croatian Society of Civil Engineers - HSGI, 2022-10-10)
Naumovski Nikola, Hristovski Viktor, Krstevska Lidija
Rail traffic is a significant source of vibration that can affect the quality of life of people living near busy railways. The paper proposes an integrated methodology for analysis of the impact of vibrations from railway traffic on people and buildings and measures for reduction of their effect. The research has grasped in-situ measurements and numerical modelling of railway traffic-induced vibrations. The proposed integrated methodological approach is specifically implemented on the section of the active railway line Kumanovo-Deljadrovce, N. Macedonia. The knowledge gained in this research is intended to represent a good basis for defining national standards for this increasingly relevant issue.
Some of the metrics are blocked by your
consent settings
Performance of CFRP-confined concrete cylinder specimens - laboratory study
(Croatian Association of Civil Engineers, 2022-03-28)
Golubka Nechevska-Cvetanovska, Artur Roshi, Jordan Bojadjiev, Julijana Bojadjieva, Zoran Trajcevski
<jats:p>The research presented in this paper focuses on the application of innovative materials for the repair and strengthening of RC columns of buildings in seismically active regions. The analytical and laboratory research for defining the compressive strength and elastic modulus of concrete cylinders confined with CFRP (Fibre Reinforced Polymers) was carried out at the Skopje-based Institute of Earthquake Engineering and Engineering Seismology – IZIIS in order to present the possibilities and benefits of using these materials. Selected results from laboratory testing of built-in materials, and some analytical results from the designed CFRP-confined RC columns for quasi static tests, are presented in this paper.</jats:p>
Some of the metrics are blocked by your
consent settings
Verification of a System for Sustainable Research on Earthquake-Induced Soil Liquefaction in 1-g Environments
(MDPI AG, 2022-09-29)
Bojadjieva, Julijana
;
Sheshov, Vlatko
;
Edip, Kemal
;
Kitanovski, Toni
<jats:p>Within the presented research, model tests were performed in 1-g conditions to investigate the liquefaction potential of Skopje sand as a representative soil from the Vardar River’s terraces in N. Macedonia. A series of shaking table tests were performed on a fully saturated, homogeneous model of Skopje sand in the newly designed and constructed laminar container in the Institute of Earthquake Engineering and Engineering Seismology (IZIIS), Skopje, N. Macedonia. The liquefaction depth in each shaking test was estimated based on the measured acceleration and pore water pressure as well as the frame movements of the laminar container. The surface settlement measurements indicated that the relative density increased by ~12% after each test. The observations from the tests confirmed that liquefaction was initiated along the depth at approximately the same time. The number of cycles required for liquefaction increased as the relative density increased. As the pore water pressure rose and reached the value of the effective stresses, the acceleration decreased, thus the period of the soil started to elongate. The results showed that the investigated Skopje sand was highly sensitive to void parameters and, under specific stress conditions, the liquefaction that occurred could be associated with large deformations. The presented experimental setup and soil material represent a well-proven example of a facility for continuous and sustainable research in earthquake geotechnical engineering.</jats:p>
Some of the metrics are blocked by your
consent settings
Quasi-static tests on RC building columns strengthened with CFRP
(Croatian Association of Civil Engineers, 2021-09)
Golubka Nechevska-Cvetanovska, Artur Roshi, Julijana Bojadjieva, Jordan Bojadjiev, Zoran Trajcevski
<jats:p>To explore the possibilities and benefits of using CFRP (Carbon Fibre Reinforced Polymers) in strengthening RC building columns, quasi-static tests (compression and bending) were carried out at the Institute of Earthquake Engineering and Engineering Seismology - IZIIS, Skopje by variation of concrete class, reinforcement percentage and by using various strengthening technologies. Some recommendations and outcomes regarding the approach, technology and conclusions drawn from practical application of these materials, are given. Based on the analysis of values obtained from nonlinear static and nonlinear time history analyses, it can be concluded that the ductility capacity for displacement of model strengthened with CFRP is greater by 60 %, while its strength capacity is greater by 7.7 % when compared to the values obtained for the model without CFRP. It can generally be concluded that CFRP systems are a very practical tool for strengthening and retrofitting concrete structures, as they can extensively improve flexural strengthening, shear strengthening, column confinement, and ductility.</jats:p>
Some of the metrics are blocked by your
consent settings
Rotation-Free Based Numerical Model for Nonlinear Analysis of Thin Shells
(MDPI AG, 2021-12-17)
Smoljanović, Hrvoje
;
Balić, Ivan
;
Munjiza, Ante
;
<jats:p>This paper presents a computationally efficient numerical model for the analysis of thin shells based on rotation-free triangular finite elements. The geometry of the structure in the vicinity of the observed triangular element is approximated through a controlled domain consisting of nodes of the observed finite element and nodes of three adjacent finite elements between which a second-order spatial polynomial is defined. The model considers large displacements, large rotations, small strains, and material and geometrical nonlinearity. Material nonlinearity is implemented by considering the von Mises yield criterion and the Levi–Mises flow rule. The model uses an explicit time integration scheme to integrate motion equations but an implicit radial returning algorithm to compute the plastic strain at the end of each time step. The presented numerical model has been embedded in the program Y based on the finite–discrete element method and tested on simple examples. The advantage of the presented numerical model is displayed through a series of analyses where the obtained results are compared with other results presented in the literature.</jats:p>
Some of the metrics are blocked by your
consent settings
Numerical modelling of saturated boundless media with infinite elements
(Springer Science and Business Media LLC, 2021-02-19)
Edip, Kemal
;
Sheshov, Vlatko
;
Wu, Wei
;
Bojadjieva, Julijana

Institute of Earthquake Engineering and Engineering Seismology

Browse

Filters

Settings

Sort By

Results per page

Search Results