• Structural Engineering and Mechanics
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• 제21권1호
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• pp.83-100
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• 2005

This paper presents results from a study to extend a performance-based shearwall selection procedure to take into account the contributions of nonstructural finish materials (such as stucco and gypsum wallboard), construction quality issues, and their effects on the displacement performance of engineered wood shearwalls subject to seismic loading. Shearwall performance is evaluated in terms of peak displacements under seismic loading (characterized by a suite of ordinary ground motion records) considering different combinations of performance levels (drift limits) and seismic hazard. Shearwalls are analyzed using nonlinear dynamic time-history analysis with global assembly hysteretic parameters determined by fitting to actual shearwall test data. Peak displacement distributions, determined from sets of analyses using each of the ground motion records taken to characterize the seismic hazard, are postprocessed into performance curves, design charts, and fragility curves which can be used for risk-based design and assessment applications.

• 한국지구과학회지
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• 제36권4호
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• pp.351-359
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• 2015

본 연구는 지진위험도 산출에서 불확실성을 줄이는 한 방법으로서 지진위험도 계산에 입력되는 파라미터들(a, b값, $M_{max}$, 감쇠식 및 지진지체구조)이 지진위험도 값에 어느 정도로 영향을 미치는지 민감도를 분석하고자 하였다. 이를 위해 지진 전문가 10명이 제시한 입력자료를 사용하였다. 그 결과 a값, $M_{max}$값이 커질수록 PGA값이 증가하였으며, b값은 작아질수록 PGA값이 커졌다. 가장 큰 영향을 미치는 파라메타는 감쇄식, b값 및 a값이며, $M_{max}$와 지진지체구조구 모델의 영향은 상당히 적었다. 따라서 영향이 큰 파라메타에 대해서는 한반도의 지진학적 특성에 적합한 값의 산출이 요구된다.

• Earthquakes and Structures
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• 제20권4호
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• pp.445-455
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• 2021

Lake Van Basin, located in Eastern Turkey, is worth examining in terms of seismicity due to large-scale losses of property and life during the historical and instrumental period. The most important and largest province in this basin is Van. Recent indicators of the high seismicity risk in the province are damage occurring after devastating earthquakes in 2011 (Mw=7.2 and Mw=5.6) and lastly in 2020 Khoy (Mw=5.9). The seismic hazard analysis for Van and its districts in Eastern Turkey was performed in probabilistic manner. Analyses were made for thirteen different districts in Van. In this study, information is given about the tectonic setting and seismicity of Van. The probabilistic seismic hazard curves were obtained for a probability of exceedance of 2%, 10% and 50% in 50-year periods. The PGA values in the Van province vary from 0.24 g - 0.43 g for earthquakes with repetition period of 475 years. Risk priorities were determined for all districts. The highest risk was calculated for Çaldıran and the lowest risk was found for Gürpınar. Risk priorities for buildings in all districts were also determined via rapid seismic assessment for reinforced-concrete and masonry buildings in this study.

• 한국지진공학회논문집
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• 제20권7_spc호
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• pp.485-494
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• 2016

The risk-based assessment, also called time-based assessment of structure is usually performed to provide seismic risk evaluation of a target structure for its entire life-cycle, e.g. 50 years. The prediction of collapse probability is the estimator in the risk-based assessment. While the risk-based assessment is the key in the performance-based earthquake engineering, its application is very limited because this evaluation method is very expensive in terms of simulation and computational efforts. So the evaluation database for many archetype structures usually serve as representative of the specific system. However, there is no such an assessment performed for building stocks in Korea. Consequently, the performance objective of current building code, KBC is not clear at least in a quantitative way. This shortcoming gives an unresolved issue to insurance industry, socio-economic impact, seismic safety policy in national and local governments. In this study, we evaluate the comprehensive seismic performance of an low-rise residential buildings with discontinuous structural walls, so called piloti-type structure which is commonly found in low-rise domestic building stocks. The collapse probability is obtained using the risk integral of a conditioned collapse capacity function and regression of current hazard curve. Based on this approach it is expected to provide a robust tool to seismic safety policy as well as seismic risk analysis such as Probable Maximum Loss (PML) commonly used in the insurance industry.

• 한국지진공학회논문집
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• 제27권1호
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• pp.69-75
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• 2023

In Korea, most nuclear power plants were designed based on the design response spectrum of Regulatory Guide 1.60 of the NRC. However, in the case of earthquakes occurring in the country, the characteristics of seismic motions in Korea and the design response spectrum differed. The seismic motion in Korea had a higher spectral acceleration in the high-frequency range compared to the design response spectrum. The seismic capacity may be reduced when evaluating the seismic performance of the equipment with high-frequency earthquakes compared with what is evaluated by the design response spectrum for the equipment with a high natural frequency. Therefore, EPRI proposed the inelastic energy absorption factor for the equipment anchorage. In this study, the seismic performance of welding anchorage was evaluated by considering domestic seismic characteristics and EPRI's inelastic energy absorption factor. In order to reflect the characteristics of domestic earthquakes, the uniform hazard response spectrum (UHRS) of Uljin was used. Moreover, the seismic performance of the equipment was evaluated with a design response spectrum of R.G.1.60 and a uniform hazard response spectrum (UHRS) as seismic inputs. As a result, it was confirmed that the seismic performance of the weld anchorage could be increased when the inelastic energy absorption factor is used. Also, a comparative analysis was performed on the seismic capacity of the anchorage of equipment by the welding and the extended bolt.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.144-147
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• 2007

Internally Confined Hollow-Concrete Filled Tube(ICH-CFT) column which has two tubes on both side of concrete, inner tube and outer tube perform great seismic abilities, ductility and absorption of energy, by the tubes and the hollow part. So this study does qualitative analysis about seismic capacities depending on parameters - diameter of column, hollow ratio, thickness of tubes - by moment-curvature analysis.

• Earthquakes and Structures
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• 제24권2호
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• pp.141-153
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• 2023

The presented paper considers infill masonry walls' influence on the seismic reliability of precast concrete frames. The recent Bojnord earthquake on May 13th, 2017 in Iran (MW 5.4) illustrated that the infill masonry walls play a crucial role in the damage extent and life safety issues of inhabitants in the precast concrete buildings. The incremental dynamic analysis (IDA) approach was used to determine the fragility curves of the represented damaged precast frame. Then, by integrating site hazard and structural fragilities, the seismic reliability of the represented precast frame was evaluated in different damage limit states. Additionally, the static pushover analysis (SPA) approach was used to assess the seismic performance assessment of the precast frame. Bare and infilled frames were modeled as 2D frames employing the OpenSees software platform. The multi-strut macro-model method was employed for infill masonry simulation. Also, a relatively efficient and straightforward nonlinear model was used to simulate the nonlinear behavior of the precast beam-column joint. The outputs show that consideration of the masonry infilled wall effect in all spans of the structural frame leads to a decrease in the possibility of exceedance of specified damage limit states in the structures. In addition, variation of hazard curves for buildings with and without consideration of infilled walls leads to a decrease in the reliability of the building's frames with masonry infilled walls. Furthermore, the lack of infill walls in the first story significantly affects the precast concrete frame's seismic reliability and performance.

• Structural Engineering and Mechanics
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• 제88권1호
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• pp.13-23
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• 2023

Seismic risk assessment studies are one of the most crucial instruments for mitigating casualties and economic losses. This work utilizes fragility curves to evaluate the seismic risk of single-story precast buildings, which are generally favored in Marmara's organized industrial zones. First, the precast building stock in the region has been categorized into nine sub-classes. Then, seven locations in the Marmara region with a high concentration of industrial activities are considered. Probabilistic seismic hazard assessments were conducted for both the soil-dependent and soil-independent scenarios. Subsequently, damage analysis was performed based on the structural capacity and mean fragility curves. Considering four different consequence models, 630 sub-class-specific loss curves for buildings were obtained. In the current study, it has been determined that the consequence model has a significant impact on the loss curves, hence, average loss curves were computed for each case investigated. In light of the acquired results, it was found that the loss ratio values obtained at different locations within the same region show significant variation. In addition, it was observed that the structural damage states change from serviceable to repairable or repairable to unrepairable. Within the scope of the study, 126 average loss functions were presented that could be easily used by non-experts in earthquake engineering, regardless of structural analysis. These functions, which offer loss ratios for varying hazard levels, are valuable outputs that allow preliminary risk assessment in the region and yield sensible outcomes for insurance activities.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.597-604
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• 2006

The seismic safety of the prestressed concrete containment building was evaluated by the seismic fragility analysis based on the nonlinear dynamic time-history analyses. Four kinds of earthquake ground motions were used for the seismic fragility analysis of the containment building to consider the potential earthquake hazard. The conventional seismic fragility analysis of the safety related structures in nuclear pouter plant have been performed by using the linear elastic analysis results for the seismic design. In this study, the displacement based seismic fragility analysis method was proposed.

• Earthquakes and Structures
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• 제13권5호
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• pp.497-507
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• 2017

Flooding induced scour has been long recognized as a major hazard to river-crossing bridges. Many studies in recent years have attempted to evaluate the effects of scour on the seismic performance of bridges, and probabilistic frameworks are usually adopted. However, direct and straightforward insight about how foundation scour affects bridges as a type of soil-foundation-structure system is usually understated. In this paper, we provide a comprehensive review of applied methods centering around seismic assessment of scoured bridges considering soil-foundation-structure interaction. When introducing these applied analysis and modeling methods, a simple bridge model is provided to demonstrate the use of these methods as a case study. Particularly, we propose the use of nonlinear modal pushover analysis as a rapid technique to model scoured bridge systems, and numerical validation and application of this procedure are given using the simple bridge model. All methods reviewed in this paper can serve as baseline components for performing probabilistic vulnerability or risk assessment for any river-crossing bridge system subject to flood-induced scour and earthquakes.