• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.5
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• pp.61-69
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• 2007

The main purpose of this study is to provide a basic information for the seismic capacity evaluation and the seismic design of low-rise reinforced concrete (RC) shear wall buildings, which are comprised of a pilotis in the first story. In this study, relationships between strengths and ductilities of each story of RC buildings with pilotis are investigated based on the nonlinear seismic response analysis. The characteristics of low-rise RC buildings with pilotis are assumed as the double degree of freedom structural systems. In order to simulate these systems, the pilotis is idealized as a degrading trilinear hysteretic model that fails in flexure and the upper story of shear wall system is idealized as a origin-oriented hysteretic model that fails in shear, respectively. Stiffness properties of both models are varied in terms of story shear coefficients and structures are subjected to various ground motion components. By analyzing these systems, interaction curves of required strengths for various levels of ductility factors are finally derived for practical purposes. The result indicates that the required strength levels derived can be used as a basic information for seismic evaluation and design criteria of low-rise reinforced concrete shear wall buildings having pilotis structure.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.5
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• pp.371-380
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• 2017

The risk-targeted seismic design concept was first included in ASCE/SEI 7-10 to address problems related to the uniform-hazard based seismic concept that has been constructed without explicitly considering probabilistic uncertainties in the collapse capacities of structures. However, this concept is not yet reflected to the current Korean building code(KBC) because of insufficient strong earthquake data occurred at the Korean peninsula and little information on the collapse capacities of structures. This study evaluates the risk-targeted seismic performance of steel ordinary concentrically braced frames(OCBFs). To do this, the collapse capacities of prototype steel OCBFs are assessed with various analysis parameters including building locations, building heights and soil conditions. The seismic hazard curves are developed using an empirical spectral shape prediction model that is capable of reflecting the characteristics of earthquake records. The collapse probabilities of the prototype steel OCBFs located at the Korean major cities are then evaluated using the risk integral concept. As a result, analysis parameters considerably influence the collapse probabilities of steel OCBFs. The collapse probabilities of taller steel OCBFs exceed the target seismic risk of 1 percent in 50 years, which the introduction of the height limitation of steel OCBFs into the future KBC should be considered.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.5
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• pp.397-404
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• 2017

The purpose of this study is to evaluate the seismic performance of Staggered Truss Frame(STF) system while changing a shape of truss. The model of this project is a office building of ten floors with Pratt, Howe, Warren, K and Vierendeel truss system applied on each model. Next step is to select the section of elements which satisfy the highest demand capacity ratio by structure design considering gravity load, earthquake load and wind load and then calculate natural period, base shear and story drifts. On the basis of these values, Capacity Spectrum Method(CSM) shows the plastic behavior of STF system such as performance point of Design Earthquake(DE) and Maximum Considered Earthquake(MCE), yield state, plastic hinge etc. to be compared with other truss systems. As a result, Vierendeel STF system especially was found to have the highest strength and stiffness to the corresponding earthquake and all the models for each truss shape fulfilled the target performance level.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.4
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• pp.439-445
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• 2020

In this paper, the seismic performance evaluation was performed on 100 existing open-cut power cable tunnels, including ones that did not consider seismic design, in order to verify that the government's demand level (seismic special grade, 0.22 g). The results of the seismic performance evaluation show that most of the tunnels have seismic performance of 0.3 to 1 g, satisfying the level of the seismic special grade and securing the seismic safety. Meanwhile, the earthquake response analysis and structural test were performed to verify the validity of the method and the results of the seismic performance evaluation of the tunnels by the response displacement method, and to verify their seismic safety. As a result, the relative displacement due to the response displacement method under the 0.22 g earthquake was conservative than the results of the earthquake response analysis, and the results of load-displacement curves and response modification coefficient calculation by real scale structural tests showed the safety of the tunnels.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.3 s.43
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• pp.1-8
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• 2005

This paper describes a new objective methodology of seismic building damage assessment which is called Advanced Component Method(ACM). ACM is a major attempt to replace the conventional loss estimation procedure, which is based on subjective measures and the opinions of experts, with one that objectively measures both earthquake intensity and the response ol buildings. First, response of typical buildings is obtained analytically by nonlinear seismic static analysis, push-over analyses. The spectral displacement Is used as a measure of earthquake intensity in order to use Capacity Spectrum Method and the damage functions for each building component, both structural and non-structural, are developed as a function of component deformation. Examples of components Include columns, beams, floors, partitions, glazing, etc. A repair/replacement cost model is developed that maps the physical damage to monetary damage for each component. Finally, building response, component damage functions, and cost model were combined probabilistically, using Wonte Carlo simulation techniques, to develop the final damage functions for each building type. Uncertainties in building response resulting from variability in material properties and load assumptions were incorporated in the Latin Hypercube sampling technique. The paper also presents and compares ACM and conventional building loss estimation based on historical damage data and reported loss data.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.6
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• pp.33-39
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• 2002

Response Modification Factor(R-factor) approach is currently implemented to reflect inelastic ductile behavior of the structures and to reduce elastic spectral demands from earthquakes to the design level. However R factors were set empirically and simply based on the professional committee consensus on observed performance of building structures during past earthquakes. Consequently some major shortcomings linked to the current R factor approach have been pointed out. Using reinforced concrete intermediate moment-resisting frames(RC IMRFs), an analytical procedure is presented in this paper to establish R factor rationally. To this end, analytical R values were evaluated based on N2 Method and compared with the values recommended by IBC 2000. Overall, the analytical results correlated well with the code values. However the results also revealed that R factor might strongly depend on the system fundamental period. As evidenced by the interstory drift index(IDI) analysis results of this study, current R-factor based(or, Life Safety based) design tends to fail in fulfilling other implicit and hopeful performance objectives such as immediate Occupancy and Collapse Prevention. Performance based design(PBD) appears to be a promising approach to meet the multi level seismic performance objectives assigned to the building structures of nowadays.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.3 s.55
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• pp.43-52
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• 2007

This study suggests a method to determine optimal seismic retrofitting schemes for existing bridges based on weighting-factored evaluation. According to the recognition for potential seismic risk, various kinds of retrofitting methods are applied to improve the seismic performance of existing bridges. However, the relevant technique is not available to select optimal retrofitting scheme for bridges now. This suggested method weights five factors, structural compatibility, economic efficacy, environmental factor, consturctability and maintenance, and draws out optimal seismic retrofitting schemes. The application of the developed method to one hundred sixty existing bridges verifies the adaptability of this method. As a result, this study provides an idealized retrofitting schemes, and the suggested method could be a guideline to determine the more cost-effective and optimal retrofitting schemes for existing bridges in Korea.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.1
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• pp.57-66
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• 2008

An experimental study was performed to evaluate seismic reduction performance and applicability of 3-dimensional floor isolation system to the main control room of nuclear power plant. A friction pendulum system(FPS) and air spring were designed and fabricated for 3-dimensional floor isolation system. Two kind of the partial experimental model of a main control room attached to the FPS and air spring were tested on the shaking table. The experimental model consisted of a control panel, a $2.5m{\times}2.5m$ access floor, four FPS and air springs. The artificial time histories based on the vertical and horizontal floor response spectrums(OBE, SSE) of the main control room were used as the earthquake input signals in the test. Compared to non-isolated system, the seismic response of experimental models using 3-dimensional floor isolation system were shown considerable seismic reduction performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.838-845
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• 2009

The inelastic response characteristics of the standard school buildings depending on selection of hysteresis models are reviewed. Three earthquake records of El-centre, Santa-Monica, Taft and three artificial earthquake records in accordance with Korea standard are used and the inelastic response characteristics such as story shear force, story drift ratio, story displacement, hinge distribution state are reviewed with various hysteresis models. As results, story shear force is increased by maximum 60% according to hysteresis model. And Story drift ratio is increased by maximum 42% according to hysteresis model. And The result with clough model shows the maximum hinge distribution state.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.5
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• pp.635-643
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• 2018

In the present study, influence of earthquake intensity range on seismic fragility analysis of a RC bridge has been evaluated. For this purpose, a RC bridge damaged by a past earthquake has been selected, and analytical model of the bridge has been developed for nonlinear dynamic time-history analysis. A total of 25 recorded earthquake motions have been employed for the nonlinear analysis from which maximum lateral drift ratio of piers are obtained. Then, seismic fragility analysis has been conducted for the bridge using the nonlinear analysis results. Probability of exceeding damage has been computed in terms of using the maximum likelihood estimation, and effect of earthquake intensity range of the motions on seismic fragility curves has been assessed analytically. Analytical predictions indicate that the earthquake intensity range is of utmost significance for rationale seismic fragility analysis reflecting a physical damage state of a bridge and seismic performance evaluation of such bridge.