• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.292-299
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• 2002

It has been realized that the design codes and underlying design concept of high seismicity region may not be appropriate to low and moderate seismicity regions. The aim of this paper is to search seismic design strategies that are appropriate to moderate seismicity regions. The characteristics of seismic hazard in moderate seismicity regions are reviewed. The seismic responses of multi-span continuous bridges subjected to the ground shaking of moderate intensity are examined. The present code on seismic design of bridges is briefly reviewed. Based on these observations, design principles and strategies appropriate to the moderate seismicity regions are proposed for the multi-span continuous bridge

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.7_spc
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• pp.517-526
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• 2016

In this paper, some popular intensity measures of earthquakes including magnitude, MMI, and PGA as well as their empirical relationships are briefly reviewed since they have been widely used without prudence by mass media, the public, and even the government when asking or expressing the seismic capacity of buildings. The basic concept of current seismic design is also presented in order to facilitate relevant discussions. It is emphasized that expressing the building seismic capacity simplistically in terms of seismological quantities or terminologies like magnitude and MMI is inherently irrational, may be misleading the stakeholders, and should be avoided. Alternative expressions, more rational and consistent with current seismic design philosophy and practice, are recommended.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.885-890
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• 2002

Pseudo dynamic test is an on-line computer control method to achieve the realism of shaking table test with the economy and versatility of the conventional quasi-static approach. Pseudo dynamic tests of four full-size RC bridge piers have been carried out to investigate their seismic performance. For the purpose of precise evaluation, the experimental investigation was conducted to study the seismic performance of the real size specimen, which is constructed for highway bridge piers in Korean peninsula. Since it is believed that Korea belongs to the moderate seismicity region, three test specimens were designed in accordance with limited ductility design concept. Another one test specimen was nonseismically designed according to a conventional code. Important test parameters were transverse reinforcement and lap splicing. Lap splicing was frequently used in the plastic hinge region of many bridge columns. Furthermore, the seismic design code is not present about lap splice in Korean Roadway Bridge Design Code. The results show that specimens designed according to the limited ductility design concept exhibit higher seismic resistance. Specimens with longitudinal steel lap splice in the plastic hinge region appeared to significantly fail at low ductility level.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.553-558
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• 2001

Recent destructive seismic events demonstrated the importance of mitigating human casualties and serious property damages in design and construction of structures. The Korean Bridge Design Specifications (1992) adopted seismic design requirements based on the AASHTO specification, and minor modification was made in 2000. The longitudinal steel connection of reinforced concrete bridge column is sometimes practically unavoidable. The longitudinal reinforcement details affect seismic performance such as flexural failure and shear failure. This research aims to develop longitudinal steel connection details with confinement steel by experimental study for seismic performance of reinforced concrete bridge columns. Quasi-static test under three different axial load levels was conducted for 12 spiral column specimens. All the column specimens had the same aspect ratio of 3.5. The column specimens were transversely reinforced with spiral and with five different longitudinal steel connection. The final objective of this study is to suggest appropriate longitudinal reinforcement connection details for the limited ductility design concept and improve construction quality.

• Journal of the Earthquake Engineering Society of Korea
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• v.19 no.3
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• pp.93-102
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• 2015

This study evaluates collapse probabilities of structures which are designed according to a domestic seismic design code, KBC2009. In evaluating their collapse probabilities, to do this, probabilistic distribution models for seismic hazard and structural capacity are required. In this paper, eight major cities in Korea are selected and the demand probabilistic distribution of each city is obtained from the uniform seismic hazard. The probabilistic distribution for the structural capacity is assumed to follow a underlying design philosophy implicitly defined in ASCE 7-10. With the assumptions, the structural collapse probability in 50 years is evaluated based on the concept of a risk integral. This paper then defines an mean value of the collapse probabilities in 50 years of the selected major cities as the target risk. Risk-targeted spectral accelerations are finally suggested by modifying a current mapped spectral acceleration to meet the target risk.

• Structural Monitoring and Maintenance
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• v.10 no.3
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• pp.243-260
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• 2023

Indonesia has had seismic codes for earthquake-resistant structures designs since 1970 and has been updated five times to the latest in 2019. In updating the Indonesian seismic codes, seismic hazard maps for design also update, and there are changes to the Peak Ground Acceleration (PGA). Indonesian seismic design uses the concept of building performance levels consisting of Immediate occupancy (IO), Life Safety (LS), and Collapse Prevention (CP). Related to this performance level, cases still found that buildings were damaged more than their performance targets after the earthquake. Based on the above issues, this study aims to analyze the performance of base isolation design on existing target buildings and analyze the seismic fragility for a case study in Indonesia. The target building is a prototype design 8-story medium-rise residential building using the reinforced concrete moment frame structure. Seismic fragility analysis uses Incremental Dynamic Analysis (IDA) with Nonlinear Time History Analysis (NLTHA) and eleven selected ground motions based on soil classification, magnitude, fault distance, and earthquake source mechanism. The comparison result of IDA shows a trend of significant performance improvement, with the same performance level target and risk category, the base isolation structure can be used at 1.46-3.20 times higher PGA than the fixed base structure. Then the fragility analysis results show that the fixed base structure has a safety margin of 30% and a base isolation structure of 62.5% from the PGA design. This result is useful for assessing existing buildings or considering a new building's performance.

• Earthquakes and Structures
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• v.11 no.6
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• pp.925-942
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• 2016

With ongoing development of earthquake engineering research and the lessons learnt from a series of strong earthquakes, the seismic design concept of "resilience" has received much attention. Resilience describes the capability of a structure or a city to recover rapidly after earthquakes or other disasters. As one of the main features of urban constructions, tall buildings have greater impact on the sustainability and resilience of major cities. Therefore, it is important and timely to quantify their seismic resilience. In this work, a quantitative comparison of the seismic resilience of two tall buildings designed according to the Chinese and US seismic design codes was conducted. The prototype building, originally designed according to the US code as part of the Tall Building Initiative (TBI) Project, was redesigned in this work according to the Chinese codes under the same design conditions. Two refined nonlinear finite element (FE) models were established for both cases and their seismic responses were evaluated at different earthquake intensities, including the service level earthquake (SLE), the design-based earthquake (DBE) and the maximum considered earthquake (MCE). In addition, the collapse fragility functions of these two building models were established through incremental dynamic analysis (IDA). Based on the numerical results, the seismic resilience of both models was quantified and compared using the new-generation seismic performance assessment method proposed by FEMA P-58. The outcomes of this study indicate that the seismic resilience of the building according to the Chinese design is slightly better than that according to the US design. The conclusions drawn from this research are expected to guide further in-depth studies on improving the seismic resilience of tall buildings.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.179-186
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• 2001

It has been known that lap splicing in the longitudinal reinforcement of bridge columns is not desirable for seismic performance, but it is sometimes unavoidable. Lap splices were usually be located in the plastic hinge region of most bridge columns that were constructed before the adoption of the seismic design provision of Korea Bridge Design Specification on 1992. This research is to evacuate the seismic performance of reinforced concrete bridge piers with lap splicing of longitudinal reinforcement in the plastic hinge region, and to develop the enhancement scheme of their seismic capacity by retrofitting with glassfiber sheets and to develop appropriate limited ductility design concept in low or moderate seismicity region. Nine test specimens in the aspect ratio of 4.0 were made with three confinement ratios and three types of lap splicing. Quasi-static tests under three different axial load levees were conducted. It has been observed that displacement ductility ratios of test columns with lap splicing were significantly reduced.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.3
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• pp.47-55
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• 2003

This study proposed a convenient seismic design procedure for buckling-restrained braced frames based on the equivalent energy concept. The design process begins with the computation of input energy from response spectrum. Then the elastic energy and plastic energy are computed based on the equal energy concept. The computed plastic energy is distributed to each story along energy distribution ratio and the cross-sectional area of each brace is computed so that all the plastic energy is dissipated by the brace. The proposed procedure was applied to the design of three-, six-, and twenty-story steel frames with buckling-restrained braces, and artificial earthquake records were used for verification of the proposed method. According to analysis results, top story displacements of the low-rise structure satisfies the given target displacement however that of the twenty-story structure was much smaller than the given target displacement.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.345-352
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• 2001

Recent destructive seismic events demonstrated the importance of mitigating human casualties and serious property damages in design and construction of structures. The Korean Bridge Design Specifications (1992) adopted seismic design requirements based on the AASHTO specification, and minor modification was made in 2000. The longitudinal steel connection of reinforced concrete bridge column is sometimes practically unavoidable. The longitudinal reinforcement details affect seisimc performance such as flexural failure and shear failure. This research aims to develop longitudinal steel connection details with confinement steel by experimental study for seismic performance of reinforced concrete bridge columns. Quasi-static test under three different axial load levels was conducted for 12 spiral column specimens. All the column specimens had the same aspect ratio of 3.5. The column specimens were transversely reinforced with spiral and with five different longitudinal steel connection. The final objective of this study is to suggest appropriate longitudinal reinforcement connection details for the limited ductility design concept and improve construction quality.