• Earthquakes and Structures
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• v.19 no.2
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• pp.145-156
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• 2020

The 24 January 2020 (Mw=6.8) earthquake with epicentre in Elazığ (Sivrice) on the East Anatolian Fault Zone caused loss of life and property. The information was given about the seismotectonic setting and regional seismicity along this fault zone and aftershock activity and ground motion data of this earthquake. Earthquake parameters were obtained for five different earthquake stations which were closer to the epicentre. Horizontal and vertical design spectra were obtained for the geographic locations for each earthquake station. The obtained spectra for the earthquake epicentre were compared with selected appropriate attenuation relationships. The damages after earthquake were evaluated via geotechnical and structural aspects. This study also aims to investigate the cause-effect relationships between structural damage in reinforced-concrete and masonry structures, respectively. The lack of engineering services was effective on the amount of damage in masonry structures. Insufficient reinforcement and concrete strength, dimensions and inadequate detailing increased the amount of damage in reinforced-concrete structures. Importance should be given to negative parameters that may weaken the defence mechanisms of structures for earthquake-resistant structural design.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.125-132
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• 2003

This paper clarifies the problems which structural engineers would have when the high-rise reinforced concrete building structures with vertical and plan irregularities are to be designed against earthquakes. The most important problems appear to be as follows: (1) ambiguity in defining the principal direction of the structure and the dynamic base shear, (2) the methodology how to account for the accidental eccentricity when the modal analysis should be conducted as required for the torsionally irregular structures, and (3) the choice of 100/30 and SRSS methods to take into account the effect of the critical direction of earthquake.

• Structural Engineering and Mechanics
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• v.5 no.2
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• pp.149-165
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• 1997

A dynamic time-history analysis of the coupled internals and core in the vertical direction is performed as a part of the fuel assembly qualification program. To reflect the interaction between the fuel rods and grid cage, friction element is developed and is implemented. Also derived here is a method to calculate a hydraulic force on the reactor internals due to pipe break. Peak responses are obtained for the excitations induced from earthquake and pipe break. The dynamic responses such as fuel assembly axial forces and lift-off characteristics are investigated.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.1
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• pp.113-122
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• 1999

The importance of the vertical response of a structure was well recognized after the Hyogoken-Nanbu earthquake of Japan. However, most of the seismic design codes does not specified the site sail profiles, and the sail and foundations conditions were mostly neglected in the vertical seismic analyses of a structure. In this paper, the effects of foundation size, sail layer depth under the foundation, foundation embedment and pile foundation on the vertical seismic response spectra for both surface and embedded mat foundation were studied to investigate the effects of the soft soil layer on the vertical response of a structure excited with the vertical components of Taft and El Centro earthquakes, considering the sail profile types of $S_A,S_C,S_E$ in UBC-97, the medium and large size foundations, the soil layer depth under the foundation of 30 and 60m, the foundation embedment of 0 and 15m, and the precast reinforced concrete bearing piles installed in the soft soil deposit. According to the study results, the foundation size has a little effect on the vertical seismic response, However, the soil layer depth under the foundation of 60m has to be considered for the vertical seismic analysis of a structure as for the horizontal one. The embedded pile foundations as well as the surface ones built on the soft soil layer amplified the vertical seismic response of a structure very much.

• Geomechanics and Engineering
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• v.34 no.4
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• pp.381-396
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• 2023

The present paper evaluates seismic bearing capacity of rock masses subjected to loads of strip footings using the upper bound method. A general formula was proposed to evaluate the seismic bearing capacity considering both the horizontal and vertical accelerations of the earthquake and the effects of footing embedment depth simultaneously. Modified Hoek-Brown failure criterion was employed for the rock mass. Some comparisons were made with the available solutions and the finite element numerical models to show the accuracy of the developed upper bound formulations. The obtained results show significant improvement compared to the other available solutions. By increasing the horizontal earthquake acceleration from 0.1 to 0.3, the bearing capacity was reduced by up to 39%, while the effect of the vertical earthquake acceleration depends on its direction. An upward acceleration in the range of zero to 0.2 results in an increase in the bearing capacity by up to 24%, while the downward earthquake acceleration has an adverse effect. Also, by increasing the embedment depth of the footing from zero to 5 times the footing width, the value of seismic bearing capacity was raised about 86%. The obtained results were presented as design tables for use in practical applications.

• Advances in concrete construction
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• v.10 no.4
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• pp.333-343
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• 2020

In the architectural design process, the selection and configuration of the structural system significantly affect the earthquake behaviours of the reinforced concrete buildings. The main purpose of this study, the effects on the earthquake performances and the rough construction cost of the buildings of the slab type in reinforced concrete buildings are to examine comparatively for different local soil classes. The results obtained from this study have been determined that the building model having slabs with beams is safer compared to other types of slabs, especially when considering the vertical bearing structural elements (columns). It also shows that other types of slab, except for slab with beams, reduce the earthquake performances of reinforced concrete buildings, increase the displacement values, 1st natural vibration period values and the cost of rough construction. This matter reveals that slab type is quite important and the preference of beamed slabs in reinforced concrete buildings to be constructed in earthquake zones would be more appropriate in terms of safety and cost.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.5
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• pp.311-318
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• 2016

The lead-rubber bearing (LRB) dissipates seismic energy through plastic deformation of lead core. Under large-displacement cyclic motion, the temperature increases in the lead core. The shear strength of a lead-rubber bearing is reduced due to the heating effect of the lead core. In this study, the seismic responses such as displacement increasing, shear strength and vertical stiffness degradations of LRB due to the heating effect are evaluated for design basis earthquake (DBE) and beyond design basis earthquake (150% DBE, 167% DBE, 200% DBE).

• The Journal of Engineering Geology
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• v.24 no.3
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• pp.323-332
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• 2014

The Nobi fault zone, which generated the 1891 Nobi Earthquake (M8.0), includes five or six faults distributed in and around Gifu and Aichi prefectures, Japan. Because large cities are located near the fault zone (e.g., Gifu and Nagoya), and because the zone will likely be reactivated in the future, relatively thorough surveys have been conducted on the 1891 Nobi earthquake event, examining the fault geometry, house collapse rate, and the magnitude and distribution of earthquake intensity and fault displacement. In this study, we calculated the earthquake slip along faults in the Nobi fault zone by applying a 3D numerical analysis. The analysis shows that a zone with slip displacements of up to 100 mm included all areas with house collapse rates of 100%. In addition, the maximum vertical displacement was approximately ${\pm}1700mm$, which is in agreement with the ${\pm}1400mm$ or greater vertical displacements obtained in previous studies. The analysis yielded a fault zone with slip displacements of > 30 mm that is coincident with areas in which house collapse rates were 60% of more. The analysis shows that the regional slip sense was coincident with areas of uplift and subsidence caused by the Nobi earthquake.

• Journal of Korean Association for Spatial Structures
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• v.9 no.1
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• pp.69-78
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• 2009

Recent earthquake, such as the Northridge(1994), the Kobe(1995) and the Izmit(1990) earthquakes, gave serious damage in various buildings and bridges by the vertical seismic component. Most of the seismic designs neglect the vertical seismic component for usual frame structures. The purpose of this study is to evaluate the effects of the vertical seismic component and to compare the axial force of columns and plastic rotation angle of the analytical models in these effects. The vertical seismic component produced a large increment of axial force in columns. And the vertical seismic component caused a significant increase of the damage in the columns. As analysis result, increase of axial force cause the damage of columns and give possibility of story collapse mechanism of the structure system. Therefore, area that near fault ground motion is expected may be consider the effect of vertical component of seismic ground motions.

• Structural Engineering and Mechanics
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• v.61 no.5
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• pp.663-674
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• 2017

The determination of the fundamental period of vibration of a structure is essential to earthquake design. Current codes provide formulas for the approximate estimation of the fundamental period of earthquake-resistant building systems. These formulas are dependent only on the height of the structure or number of storeys without taking into account the presence of infill walls into the structure, despite the fact that infill walls increase the stiffness and mass of the structure leading to significant changes in the fundamental period. Furthermore, such a formulation is overly conservative and unable to account for structures with geometric irregularities. In this study, which comprises the companion paper of previous published research by the authors, the effect of the vertical geometric irregularities on the fundamental periods of masonry infilled structures has been investigated, through a large set of infilled frame structure cases. Based on these results, an attempt to quantify the reduction of the fundamental period due to the vertical geometric irregularities has been made through a proposal of properly reduction factor.