• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.720-723
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• 2004

This study is intended to propose a systematic approach for determining optimum Life-Cycle Cost (LCC)-effective seismic design for continuous PSC bridges considering lifetime expected seismic risks. In the paper, a set of cost function for LCC analysis of bridges is proposed. The total LCC functions consist of initial cost and direct/indirect damage costs considering repair/replacement costs, human losses and property damage costs, road user costs, and indirect socio-economic losses. The damage costs are expressed in terms of Park-Ang median global damage indices (Park and Ang, 1985) and lifetime damage probabilities. The proposed approach is applied to model bridges of both moderate seismicity regions like Korea and high seismicity regions like Japan. Since, in case of bridges, a number of parameters may have an influence on optimal target reliability, various sensitivity analyses are performed in this study. It may be expected that the proposed approach can be effectively utilized for the development of cost-effective performance criteria for design and upgrading of various types of bridges as well as continuous PC bridges.

• Earthquakes and Structures
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• v.9 no.4
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• pp.893-910
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• 2015

Earthquake safety of existing buildings has gained considerable importance after earthquakes which have occurred in our country especially in the last 30 years. Performance based assessment methods have been widely used for existing reinforced concrete structures. This study aims to investigate the earthquake performances of the building stock located in Van Lake basin in Eastern Anatolia of Turkey. The case study of buildings has been modeled on and the structural performances have been determined by employing the non-linear methods described in the latest Turkish Earthquake Code published in 2007. The Van lake basin is located on the very seismically active in a region. On October 23, 2011, a magnitude of Mw 7.2 earthquake struck the Van province in eastern Turkey. The earthquake ground motion was recorded as about 0.1g in Bitlis province. Performance evaluations have been performed by taking samples from each district consisting urban building stocks of Bitlis. A total of 16 reinforced concrete buildings have been evaluated. Among them, 53% of those buildings were determined in the Fully Operational performance level; 13% of them in the Life Safety performance and 34% of them could not be evaluated because of the ratio of the effective mass of first mode to the total mass of the buildings was smaller than 0.70. Therefore, incremental equivalent seismic load methods, which are a part of Turkish Earthquake Code -2007, cannot be used.

• Earthquakes and Structures
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• v.18 no.2
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• pp.249-261
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• 2020

Seismic loss estimation studies require fragility curves which are usually derived using ground motion datasets. Ground motion records can be either in the form of recorded or simulated time histories compatible with regional seismicity. The main purpose of this study is to investigate the use of alternative ground motion datasets (simulated and real) on the fragility curves. Simulated dataset is prepared considering regional seismicity parameters corresponding to Erzincan using the stochastic finite-fault technique. In addition, regionally compatible records are chosen from the NGA-West2 ground motion database to form the real dataset. The paper additionally studies the effects of hazard variability and two different fragility curve derivation approaches on the generated fragility curves. As the final step for verification purposes, damage states estimated for the fragility curves derived using alternative approaches are compared with the observed damage levels from the 1992 Erzincan (Turkey) earthquake (Mw=6.6). In order to accomplish all these steps, a set of representative masonry buildings from Erzincan region are analyzed using simplified structural models. The results reveal that regionally simulated ground motions can be used alternatively in fragility analyses and damage estimation studies.

• Structural Engineering and Mechanics
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• v.39 no.4
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• pp.559-578
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• 2011

In regions of high seismic risk, high-strength concrete (HSC) columns of tall buildings are designed to be fully ductile during earthquake attack by providing substantial amount of confining steel within the critical region. However. in areas of low to moderate seismic risk, the same provision of confining steel is too conservative because of the reduced seismic demand. More critically, it causes problematic steel congestion in the beam-column joints and column critical region. This will eventually affect the quality of concrete placing owing to blockage. To relieve the problem, the confining steel in the critical region of HSC columns located in low to moderate seismicity regions can be suitably reduced, while maintaining a limited ductility level. Despite the advantage, there are still no guidelines developed for designing limited ductility HSC columns. In this paper, a formula for designing limited ductility HSC columns is presented. The validity of the formula was verified by testing half-scale HSC columns subjected to combined high-axial load and flexure, in which the confining steel was provided as per the proposed formula. From the test results, it is evident that the curvature ductility factors obtained for all these columns were about 10, which is the generally accepted level of limited ductility.

• Economic and Environmental Geology
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• v.18 no.2
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• pp.167-175
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• 1985

Geothermal heat flow distribution of Korea is investigated in the light of geophysical data, seismicity, tectonics and gravity as well as heat flow measurements and surface temperature of hot springs. The average heat flow in Korea is found to be $1.65{\mu}cal/cm^2{\cdot}sec$ that is greater than the world's average ($1.5{\mu}cal/cm^2{\cdot}sec$). The high heat flow is located at the regions of high seismicity in Korea. They are found to be Bugok of south central, and Haeundae, Pohang and Dongnae of the southest coast in the Peninsula. The anomalously high heat flow, equal to or greater than $1.93{\mu}cal/cm^2sec$ is found in the Kyongsang Basin, indicating that it is extended from the spreading of the East Sea (Japan Sea) and its origin.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.468-476
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• 2000

The Criteria of strong motion seismograph installed at free surface and structure is developed as a cooperative project of KEERC considering seismicity and state of seismic instrumentation of Korea. The background of this development and basic concepts are summarized in this report. The criteria of seismic sensor and recorder is also introduced. It is highly recommended to apply this criteria to installation and operation of seismograph at free surface and structure.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.288-295
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• 2000

As the level of earthquake intensity in Korea is considered to be moderate, some structures or structural elements may be subjected to the reduced ductility demand, in contrast to the structures in high seismicity, due to the large inherent strength induced by gravity loads. New Zealand Standard(NZS) deals with these structures within the category of structures of limited ductility. This paper briefly reviews the concept of structures of limited ductility in NZS, and its applicability to Korean case. A structural wall system which is used as the structural system for typical apartments is taken as an example for the illustration.

• Journal of the Korean Professional Engineers Association
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• v.41 no.4
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• pp.47-51
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• 2008

The different result and response of the earthquakes, occurred consecutively at China and Japan in May and June. respectively, is suggestive of the importance of preparedness against earthquake disaster. We learned lesson, although indirect, that the earthquake early warning. earthquake-resistant design, and people's concepts on earthquake can greatly reduce the earthquake hazards. The more preparedness we have in present, the less hazards we will experience for future.

• Korean Journal of Geomatics
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• v.3 no.2
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• pp.141-148
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• 2004

This paper deals with the characteristics of strain pattern by using permanent GPS stations in Korea in terms of seismic activity and tectonics. Fourteen GPS stations involved in precise baseline vector solution and horizontal strain components were calculated using the differences of mean baseline from ten deily solutions during the time span of three years. The mean rate of maximum shear strain if 0.12 $\mu$/yr. The mean direction of principal axes of the compression is about $85^{\circ}$ N.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.677-682
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• 1999

In this paper, the basic concepts and main characteristics in Eurocode 8, which deals with earthquake-resistant design, are reviewed regarding the design of reinforced concrete structures. Eurocode uses the limit-state design method to satisfy the requirements of safety and serviceability. This kind of information can serve to establish the up-coming Korean seismic code which is comprehensive and appropriate to the moderate seismicity region by constituting an important part in the basic data-pool.