• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.1 s.16
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• pp.23-32
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• 2005

A significant development has been made on earthquake resistant designs on many structures since the Korean government has begun modern earthquake hazard reduction programs after recognizing potential disastrous consequences of seismic events following the Kobe earthquake in 1995. However, some structures such as slope structures still haven't get ready for their own seismic design guidelines in Korea. Therefore, only a few organizations of Korea adopt seismic design for slopes relying on designers' judgments at present. This paper introduces domestic and foreign research activities on seismic slope stability and an idea of Korean earthquake resistant design method for slopes including alternatives of earthquake resistant design application according to designers' judgment considering construction budget, importance, restoration and so on. Afterwards, seismic data accumulation on slope stability of Korea is necessary to induce a more definite Korean earthquake resistant design method.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.3 s.43
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• pp.23-32
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• 2005

Torsional behavior of eccentric structure under seismic leading may cause the stress and/or deformation concentration, which arouse the failure of the structure in an unexpected manner. This study suggests D-R relationship which shows the overall displacement and rotation of the system based on the ultimate displacement capacity of the each lateral load resistant member. Using the suggested D-R relationship and displacement spectrum, the seismic assessment is conducted and verified in comparison with the time history analysis result. Multi-level seismic assessment Is considered which takes multiple seismic hazard levels and respective performance levels into account. Finally, based on the seismic assessment result, seismic rehabilitation process is presented. In this research, two rehabilitation methods are considered. One is done by means of stiffening/strengthening the seismic resistant members, and the other is based on the member ductility. Especially, in the first method, to optimize the rehabilitation result, the rehabilitation problem is modeled as an optimization problem, and solved using BFGS quasi-Newton optimization method.

• Structural Engineering and Mechanics
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• v.59 no.3
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• pp.387-401
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• 2016

This paper takes a half-through steel truss arch bridge as an example. A seismic analysis is conducted with nonlinear finite element method. Contrast models are established to discuss the effect of simplified method for main girder on the accuracy of the result. The influence of seismic wave direction and wave-passage on seismic behaviors are analysed as well as the superstructure and arch ring interaction which is mostly related with the supported bearings and wind resistant springs. In the end, the application of cable-sliding aseismic devices is discussed to put forward a layout principle. The main conclusions include: (1) The seismic response isn't too distinctive with the simplified method of main girder. Generally speaking, the grillage method is recommended. (2) Under seismic input from different directions, arch foot is usually the mostly dangerous section. (3) Vertical wave input and horizontal wave-passage greatly influence the seismic responses of arch ring, significantly increasing that of midspan. (4) The superstructure interaction has an obvious impact on the seismic performance. Half-through arch bridges with long spandrel columns fixed has a less response than those with short ones fixed. And a large stiffness of wind resistant spring makes the the seismic responses of arch ring larger. (5) A good isolation effectiveness for half-through arch bridge can be achieved by a reasonable arrangement of CSFABs.

• Computers and Concrete
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• v.30 no.2
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• pp.113-126
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• 2022

Reinforced concrete bearing walls (RCBWs) are one of the most applicable structural systems. Therefore, vulnerability analysis and rehabilitation of the RCBW system are of great importance. In the present study, in order to the more precise investigation of the performance of this structural resistant system, pushover and nonlinear time history analyses based on several assumptions drawing upon experimental research were performed on several models with different stories. To validate the nonlinear analysis method, the analytical and experimental results are compared. Vulnerability evaluation was carried out on two seismic hazard levels and three performance levels. Eventually, the need for seismic rehabilitation with the basic safety objective (BSO) was investigated. The obtained results showed that the studied structures satisfied the BSO of the seismic rehabilitation guidelines. Consequently, according to the results of analyses and the desired performance, this structural system, despite its high structural weight and rigid connections and low flexibility, has integrated performance, and it can be a good option for earthquake-resistant constructions.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.11c
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• pp.69-83
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• 1999

Soil-reinforced segmental retaining walls(SRW) have been proven to be high earthquake-resistant structure during recent earthquakes in United States and Japan. The mechanicals behavior of the SRWs under seismic loading, however, has not been fully understood. Although the seismic design issues for the civil engineering structures have gained much attention in Korea due to the increase in frequency of earthquake occurrence, the seismic design for the SRWs has not been being implemented. This study has been undertaken with the aim of developing a more rational seismic design/analysis method for soil-reinforced segmental retaining walls. This paper present fundamentals of current seismic design/analysis method and the results of a comparative study between NCMA and FHWA design guidelines, Practical implications of the findings from this study are discussed in great detail.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.36 no.1
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• pp.137-146
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• 2020

In this study, various application schemes of seismic isolation system which can be applied to Hanok have been studied by analyzing its structural characteristics under seismic load. Structural stability of Hanok is more required against seismic load as Hanok becomes long-spanned and multi-storied. To meet this goal, it becomes necessary to study more advanced technology such as seismic isolation design as well as seismic control design and seismic resistant design suitable to Hanok. Seismic isolation systems have been successfully applied to RC and steel structures to improve structural performance during earthquakes. Based on these previous study, we proposed four application schemes of seismic isolation design suitable for Hanok and analyzed their structural characteristics and applicability to Hanok in conceptual level based on its structural characteristics. The proposed four schemes are base isolation method, ground isolation method, roof isolation method and intermediate-story isolation method. The applicability of the proposed method was evaluated by performing boundary nonlinear dynamic analysis to the typical Hanok for the two types of isolation method, that is, ground isolation method and roof isolation method, and the results showed that the proposed methods produced good performance enough to be applied to Hanok.

• Structural Engineering and Mechanics
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• v.71 no.4
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• pp.417-432
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• 2019

Seismic performance analysis of steel-brace reinforced concrete (RC) frame using topology optimization in highly seismic region was discussed in this research. Topology optimization based on truss-like material model was used, which was to minimum volume in full-stress method. Optimized bracing systems of low-rise, mid-rise and high-rise RC frames were established, and optimized bracing systems of substructure were also gained under different constraint conditions. Thereafter, different structure models based on optimized bracing systems were proposed and applied. Last, structural strength, structural stiffness, structural ductility, collapse resistant capacity, collapse probability and demolition probability were studied. Moreover, the brace buckling was discussed. The results show that bracing system of RC frame could be derived using topology optimization, and bracing system based on truss-like model could help to resolve numerical instabilities. Bracing system of topology optimization was more effective to enhance structural stiffness and strength, especially in mid-rise and high-rise frames. Moreover, bracing system of topology optimization contributes to increase collapse resistant capacity, as well as reduces collapse probability and accumulated demolition probability. However, brace buckling might weaken beneficial effects.

• Earthquakes and Structures
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• v.4 no.4
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• pp.341-363
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• 2013

Earthquake response calculation, parametric analysis and seismic parameter optimization of base-isolated structures are some critical issues for seismic design of base-isolated structures. To calculate the earthquake responses for such non-symmetric and non-classical damping linear systems and to implement the earthquake resistant design codes, a modified complex mode superposition design response spectrum method is put forward. Furthermore, to do parameter optimization for base-isolation structures, a graphical approach is proposed by analyzing the relationship between the base shear ratio of a seismic base-isolation floor to non-seismic base-isolation one and frequency ratio-damping ratio, as well as the relationship between the seismic base-isolation floor displacement and frequency ratio-damping ratio. In addition, the influences of mode number and site classification on the seismic base-isolation structure and corresponding optimum parameters are investigated. It is demonstrated that the modified complex mode superposition design response spectrum method is more precise and more convenient to engineering applications for utilizing the damping reduction factors and the design response spectrum, and the proposed graphical approach for parameter optimization of seismic base-isolation structures is compendious and feasible.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.2
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• pp.121-126
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• 2002

Due to few earthquakes in our country, one generally has thought to be safe from earthquakes. However, severe earthquakes occurred in Dangsan and Hyogohyeon which one had regarded as the zone that had not been risky for earthquakes, so that so many people died and a lot of buildings and bridges were destroyed. This event surprised our country and we undertook preparation for earthquakes on the full scale. The concept of seismic design was induced in the country which was poor in it for the scarcity of recognition and insufficiency of funds. Recently, many specialists are enforcing the provisions of seismic design. Therefore, this study introduces the method which combines PC-LEADeR( design program for L.R.B.) with LUSAS(linear elastic analysis) and performs the seismic isolation design more elaborately and simply. It verifies the propriety of that method, and it also examine the factors that affect the response of the bridges. Seismic isolation design for bridge using L.R.B. provides both economical efficiency and superior seismic performance. Second, the results between by the method proposed and by time history analysis have 20% error at the maximum. That is, the method proposed very appropriate.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.2
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• pp.149-154
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• 2012

While the Earthquake Resistant Design Part of Korean Roadway Bridge Design Code provides design procedures for the No Collapse Requirement, requirements for the Serviceability Limit State are not clearly provided. The basic design method to meet the No Collapse Requirement is the spectrum analysis method using response modification factors and the Serviceability Limit State is determined by both the importance factor and the response modification factor applied in the design procedure. The importance factor can be simply applied according to the bridge importance category, however, in moderate/low seismic regions the application of the response modification factor may bring different result according to design conditions. In this study, for a typical bridge in the moderate/low seismic regions, determination procedures for the Serviceability Limit State are reviewed by carrying out earthquake resistant design and supplementary provisions for the Earthquake Resistant Design Part are identified based on the study results.