• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.1
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• pp.10-18
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• 2022

This report describes the development and stability evaluation of a seismic retrofit method to evaluate the seismic performance of existing school buildings by analyzing the earthquake waveforms that occurred in Korea. Currently, Facilities for seismic retrofit designed for excessive reinforcement are being applied. To compensate for this, optimised the retrofit mothod suitable for domestic situation considering the characteristics of the seismic region, generated a Korean-style artificial seismic wave that meets the seismic design criteria, which is less frequent than other countries.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.1
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• pp.65-72
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• 2009

‘Korean Highway Bridge Design Code’ provides the spectrum analysis method with response modification factors for the seismic design of typical bridges. However, considering that korean peninsula is classified as moderate seismic regions and domestic circumstances for bridge design and construction are different from other countries, the applicability of this code is not yet proved. Therefore it is required to verify that applying the spectrum analysis method fulfills the no collapse requirement which is set forth as the basic seismic design concept. In this study two typical bridges with T and ${\prod}$ type piers are selected as analysis bridges and seismic designs are carried out by applying the spectrum analysis method with design conditions given for moderate seismic regions. Based on the results obtained through deign procedures, the role of the response modification factors and fulfillment of the no collapse requirement are discussed, from which supplementary provisions for the design code are identified.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.75-84
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• 1998

Korea is located in either low or moderate seismicity continental region. It is realized that design codes and underlying design concepts of high seismicity region may not be appropriate to low or moderate seismicity region. In this paper, test results on the seismic response of structures without seismic detailing are reexamined and compared with numerical analysis results. The seismic design concept based on limited ductility is proposed as an alternative seismic design approach in moderate seismicity regions.

• Journal of the Korean GEO-environmental Society
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• v.16 no.1
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• pp.17-27
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• 2015

Recently, Korean government has tried out to set up earthquake hazards prevention system. In the system, several geotechnical hazard maps including liquefaction hazard map and landslide hazard map for the whole country have drawn to consider the domestic seismic characteristics. To draw the macro liquefaction hazard map, big data of site investigations in metropolitan areas and provincial areas has to be verified for its application. In this research, we carried out site response analyses using 522 borehole site investigation data in S city during a desirable earthquake. The soil classification was separately compared to shear wave velocity considering the uncertainty of site investigation data. Probability distribution and statistical analysis for the results of site response analyses was applied to the feasibility study. Finally, we suggest a new site amplification coefficient, hereby presented with the similar results of liquefaction hazard mapping using the calculated liquefaction potential index by the site response analyses. Above-mentioned study will be expected to help to follow research and draw liquefaction hazard map in moderate seismic region.

• Journal of the Korean Geotechnical Society
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• v.20 no.7
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• pp.127-140
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• 2004

Conventional methods for the assessment of liquefaction potential were primarily for areas of severe earthquake zones (M=7.5) such as North America and Japan. Detailed earthquake related researches in Korea started in 1997, including development of the seismic design standards for port and harbour structures, which was later completed in 1999. Because most contents in the guidelines were quoted through literature reviews from North America and Japan, which are located in strong earthquake region, those are not proper in Korea, a moderate earthquake region. This requires further improvement of the present guidelines. Considering earthquake hazard data in Korea, use of laboratory tests based on irregular earthquake motion appears to be effective to reflect the dynamic characteristics of soil more realistically than those using simplified regular loading. In this study, cyclic triaxial tests using irregular earthquake motions are performed with different earthquake magnitudes, relative densities, and fines contents. Assessment of liquefaction potential in moderate earthquake regions is discussed based on various laboratory test results. Effects of these components on dynamic behavior of soils are discussed as well. From the test results, screening limits and magnitude scaling factors to determine the soil liquefaction resistance strength in seismic design were re-investigated and proposed using normalized maximum stress ratios under real irregular earthquake motions.

• 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 Korean Society of Hazard Mitigation
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• v.8 no.5
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• pp.1-6
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• 2008

Most of seismic design code provisions provide the design response spectra for defining design earthquake ground motions. The design spectra in the code provisions generally come under the 5% of critical damping value, which corresponds to the responses of common structure under the design earthquake. Energy dissipation devices and seismic isolation systems became more popular and the design response spectra at higher damping levels are required. Damping coefficients can be effectively used in conversion of 5%-damped design spectra into other damping levels. These coefficients in the current seismic design code provisions are based on the strong ground motion records. Since the weak and moderate earthquake data have different characteristics from those of strong earthquake data, the application of these coefficients should be investigated in the weak and moderate earthquakes zones. In this study, damping coefficients based on the weak and moderate ground motions were developed and compared to those of current seismic design code provisions.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.3 s.49
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• pp.125-134
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• 2006

Conventional methods for the assessment of liquefaction potential were primary for severe earthquake regions $(M{\geq}7.5)$ such as North America and Japan. In Korea, an earthquake related research has started in 1997, but most contents in the guidelines were still quoted from literature reviews of North America and Japan, which are located in strong earthquake region. Those are not proper in a moderate earthquake regions including Korea. Also the equivalent uniform stress concept (Seed & Idriss, 1971) using regular sinusoidal loading which is used, in a conventional method for the assessment of liquefaction potential, can't reflect correctly the dynamic characteristics of real irregular earthquake motions. In this study, cyclic triaxial tests using irregular earthquake motions are performed with different earthquake magnitudes, relative densities, and fines contents. Assessment of liquefaction potential in moderate earthquake regions is discussed based on various laboratory test results. From the results, screening limits in seismic design were re-investigated and proposed using normalized maximum stress ratios under real irregular earthquake motions. Also from the tests using constant wedge loading and incremental wedge loading, the characteristics of liquefaction resistance of saturated sand under irregular ground motions are investigated.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.569-576
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• 2003

Based on the equivalent uniform stress concept Presented by Seed and Idriss, sinusoidal cyclic loads which simplified earthquake loads have been applied in evaluating the liquefaction resistance strength experimentally. However, the liquefaction resistance strength of soil based on the equivalent uniform stress concept can not exactly reflect the dynamic characteristics of the irregular earthquake motion. The liquefaction assessment method which was invented by using the equivalent uniform stress concept is suitable for the severe earthquake region such as Japan or USA, so the proper method to Korea is needed. In this study, estimation of the resistance to liquefaction was conducted by applying real earthquake loading to the cyclic triaxial test. From the test results, the characteristics of the fine sand under moderate earthquake were analyzed and compared with the results under strong earthquakes. Typically real earthquake loads used in this study are divided into two types - impact type and vibration type. Furthermore, results of the liquefaction resistance strength based on the equivalent uniform stress concept and tile concept using real earthquake loading were compared.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.4
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• pp.83-94
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• 1999

High-strength concrete has demonstrated characteristics of both increased strength and enhanced durability; hence its use has become more and more widespread. But, due to the lack of experimental evidance on the seismic performance of frame members constructed with high-strength concrete, the current codes of their design provisions are based on normal concrete test. The purpose of this study is to compare the response of the high-strength concrete beam-column-slab subassemblies with the response of a normal-strength concrete specimens. Four assemblies $(f_c'=240kg/\textrm{cm}^2, f_c'=700kg/\textrm{cm}^2)$ with 2/3 scale were designed and tested to investigate seismic behavior.