• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.163-170
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• 2002

A new seismic design criteria of electric transmission and substation facilities has been proposed. For this propose, the historic data of the earthquake damage and the state-of-the-art of the facilities were carefully reviewed and evaluated. Based on the results, a most reasonable and efficient design criteria has been extracted and proposed for the practical design of the facilities. The criteria is expected to be effectively used for obtaining the seismic safety of newly constructed or extensioning facilities. However, an independent criteria is required to evaluate and improve the seismic capacity of existing facilities

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.10
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• pp.171-180
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• 2019

In Korea, the seismic design of non-structural elements was interested by Earthquake of the 2016 Gyeong-ju and 2017 Po-hang. Among the non-structural elements, the ceiling system with steel panel used in Po-hang station showed failure examples of non-seismic design ceiling. In this study, the seismic performance of suspended ceiling with steel-panel, such as those used in Po-hang Station, was evaluated by shaking table tests. The shaking table tests were performed in accordance with the ICC-ES AC156 standard with floor acceleration being applied horizontally in one direction using a $3.3{\times}3.3m^2$ frame. The ceiling system consists of steel-panels, carrying channels, main and cross T-bars, and anti-falling clips. The anti-falling clip prevents the steel panel falling completely. The shaking table test confirmed that the damage at the previous stage had a direct impact on the damage state at the next stage. Through the shaking table test, the damage state of the T-bar type steel-panel suspended ceiling system was defined.

• Earthquakes and Structures
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• v.25 no.2
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• pp.125-134
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• 2023

In the present work, a new global damage index is proposed for the seismic performance and failure analysis of concrete gravity dams. Unlike the existing indices of concrete structures, this index doesn't need scaling with an ultimate or an upper value. For this purpose, the Beni-Haroun dam in north-eastern Algeria, is considered as a case study, for which an average seismic capacity curve is first evaluated by performing several incremental dynamic analyses. The seismic performance point of the dam is then determined using the N2 method, considering multiple modes and taking into account the stiffness degradation. The seismic demand is obtained from the design spectrum of the Algerian seismic regulations. A series of recorded and artificial accelerograms are used as dynamic loads to evaluate the nonlinear responses of the dam. The nonlinear behaviour of the concrete mass is modelled by using continuum damage mechanics, where material damage is represented by a scalar field damage variable. This modelling, which is suitable for cyclic loading, uses only a single damage parameter to describe the stiffness degradation of the concrete. The hydrodynamic and the sediment pressures are included in the analyses. The obtained results show that the proposed damage index faithfully describes the successive brittle failures of the dam which increase with increasing applied ground accelerations. It is found that minor damage can occur for ground accelerations less than 0.3 g, and complete failure can be caused by accelerations greater than 0.45 g.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.74-79
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• 2009

In the case of that not considered seismic design at transformer vault which is equipped with many important electrical facilities, the facility is damaged, electrical fire breaks out and another damage may be caused due to earthquake. But seismic design has not yet applied to transformer vault in the country. Regard to seismic design method of electrical facility installed inside the building, the seismic design procedures for electrical facility is presented in this parer, which has been developed by referring "Building design standard" of domestic code and "Manual of seismic design and construction for building electrical facility" in japan. This paper may help engineers perform detail seismic design, construction and reliability inspection of electrical pipes and facilities.

• Earthquakes and Structures
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• v.23 no.5
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• pp.463-472
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• 2022

Reinforced concrete (RC) beam column joints (BCJ) have mostly exhibited poor seismic performance during several past earthquakes, typically due to the poor-quality concrete or lack of reinforcement detailing typical of pre-code design practice. The present study is motivated towards numerical simulation and seismic fragility assessment of one such RC-BCJ. The BCJ is loaded to failure and strengthened using Ultra High Performance-Hybrid Fiber Reinforced Concrete (UHP-HFRC) jacketing. The strengthening is performed for four different BCJ specimens, each representing an intermediate damage state before collapse. viz., slight, moderate, severe, and collapse. From the numerical simulation of all the BCJ specimens, an attempt is made to correlate different modelling and design parameters of the BC joint with respect to the damage states. In addition, seismic fragility analysis of the original as well as the retrofitted damaged BCJ specimens show the relative enhancement achieved in each case.

• Earthquakes and Structures
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• v.18 no.4
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• pp.423-435
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• 2020

An accurate evaluation of structural damage is essential to performance-based seismic design for the structure across the earth fissure. By comparing the calculation results from three commonly used damage models and the experimental results, a weighted combination method using Chen model was selected in this paper as the seismic damage evaluation. A numerical model considering the soil-structure interaction (SSI) was proposed using ABAQUS software. The model was calibrated by comparing with the experimental results. The results from the analysis indicated that, for the structure across the earth fissure, the existence of earth fissure changed the damage distribution of the structural members. The damage of structural members in the hanging wall was greater than that in the foot wall. Besides, the earth fissure enlarged the damage degree of the structural members at the same location and changed the position of the weak story. Moreover, the damage degree of the structure across the earth fissure was greater than that of the structure without the earth fissure under the same excitation. It is expected that the results from this research would enhance the understanding of the performance-based seismic design for the structure across the earth fissure.

• Geomechanics and Engineering
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• v.38 no.6
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• pp.621-631
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• 2024

In designing earthquake-resistant structures, we traditionally select dynamic loads based on the recurrence period of earthquakes, using individual seismic records or aligning them with the design spectrum. However, these records often represent isolated waveforms lacking continuity, underscoring the need for a deeper understanding of natural seismic phenomena. The Earth's crustal movement, both before and after a significant earthquake, can trigger a series of both minor and major seismic events. These minor earthquakes, which often occur in short time before or after the major seismic events, prompt a critical reassessment of their potential impact on structural design. In this study, we conducted a detailed tunnel response analysis to assess the impact of both single mainshock and multiple earthquake scenarios (including foreshock-mainshock and mainshock-aftershock sequences). Utilizing numerical analysis, we explored how multiple earthquakes affect tunnel deformation. Our findings reveal that sequential seismic events, even those of moderate magnitude, can exert considerable stress on tunnel lining, resulting in heightened bending stress and permanent displacement. This research highlights a significant insight: current seismic design methodologies, which predominantly focus on the largest seismic intensity, may fail to account for the cumulative impact of smaller, yet frequent, seismic events like foreshocks and aftershocks. Our results demonstrate that dynamic analyses considering only a single mainshock are likely to underestimate the potential damage (i.e., ovaling deformation, failure lining, permanent displacement etc.) when compared to analyses that incorporate multiple earthquake scenarios.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.3 s.55
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• pp.11-21
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• 2007

Potential damage and losses associated with structural systems caused by earthquake can be reduced by application of seismic design to the structures. Because the building cost required for seismic design is generally higher than the cost for non-seismic design, the application of seismic design must be justified considering both seismic performance and cost. This paper presents a risk-based fiamework for evaluation and comparison of seismic performance of structures such that necessary data can be supplied for decision making on seismic design. Seismic fragility curve is utilized for seismic risk assessment of structures, and the process for decision analysis on adaptation of seismic design is presented based on the equivalent cost model.

• Structural Engineering and Mechanics
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• v.12 no.6
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• pp.573-594
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• 2001

A two-level displacement-based design procedure is developed. To obtain the displacement demands, elastic spectra for occasional earthquakes and inelastic spectra for rare earthquakes are used. Minimum global stiffness and strength to be supplied to the structure are based on specified maximum permissible drift limits and on the condition that the structure responds within the elastic range for occasional earthquakes. The performance of the structure may be assessed by an inelastic push-over analysis to the required displacement and the evaluation of damage indices. The approach is applied to the design of a five-story reinforced concrete coupled wall structure located in the most hazardous seismic region of Argentina. The inelastic dynamic response of the structure subjected to real and artificially generated acceleration time histories is also analyzed. Finally, advantages and limitations of the proposed procedure from the conceptual point of view and practical application are discussed.

• 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.