• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.2
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• pp.187-192
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• 2016

While structures are designed within elastic range by other designs, plastic behavior of structures should be verified and controlled in order to prevent structural collapse by the earthquake resistant design. No Collapse Requirement for typical bridges is to avoid falling down of superstructure by way of plastic behavior of certain structural elements and to operate emergency vehicles after earthquake. Such plastic behavior is restricted to connections or pier columns and appropriate measures are required for each case. Earthquake Resistant Design part of Roadway Bridge Design Code provides design processes for Ductile Collapse Mechanism by forming plastic hinges at pier columns. Also for bridges with reinforced concrete piers ductility-based design processes are provided as an appendix constructing Brittle Collapse Mechanism with connection yielding. In this study, a typical bridge with steel bearing connections and reinforced concrete piers is selected and No Collapse Design procedure considering both Ductile and Brittle Collapse Mechanism is proposed together with revisions required for the Earthquake Resistant Design part.

• 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.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.2
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• pp.181-187
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• 2009

After introduction of the earthquake resistant design code, it is required to achieve seismic performance of existing bridges as well as earthquake resistant design of new bridges. The achievement of seismic performance for existing bridges should satisfy the no collapse requirement based on the basic concept of earthquake resistant design, therefore, various methods with different strengthening scale should be suggested according to bridge types and importance categories. At present for typical bridges, most studied and applied strengthening methods are bearing change, pier strengthening and shear key installation for improvement of seismic performance. In this study a typical existing bridge, for which earthquake resistant design is not considered, is selected as an analysis bridge. Design changes are carried out to satisfy the no collapse requirement by way of the ductile failure mechanism and seismic performances are checked. It is shown that the seismic performance of existing bridges can be achieved by way of redesign of bridge system, e.g. determination of pier design section for substructure and change of bearing function for connections between super/sub-structure.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.2
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• pp.149-154
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• 2012

While the Earthquake Resistant Design Part of Korean Roadway Bridge Design Code provides design procedures for the No Collapse Requirement, requirements for the Serviceability Limit State are not clearly provided. The basic design method to meet the No Collapse Requirement is the spectrum analysis method using response modification factors and the Serviceability Limit State is determined by both the importance factor and the response modification factor applied in the design procedure. The importance factor can be simply applied according to the bridge importance category, however, in moderate/low seismic regions the application of the response modification factor may bring different result according to design conditions. In this study, for a typical bridge in the moderate/low seismic regions, determination procedures for the Serviceability Limit State are reviewed by carrying out earthquake resistant design and supplementary provisions for the Earthquake Resistant Design Part are identified based on the study results.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.4
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• pp.23-31
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• 2011

To investigate the performance of apartment buildings which were built in the 1990s and which have RC bearing wall systems with coupling beams, construction drawings of 13 buildings were collected and analyzed. To evaluate the seismic performance, FEMA 356 and FEMA 440 were selected as guidelines. For the demand curve, the seismic design spectrum in KBC 2009 is used. For each building, the performance points for life safety and the collapse prevention state are calculated. It was found that 9 out of 13 buildings (about 70%) showed damage more severe than the collapse prevention level at the performance point and more damage could be seen at the coupling beams than the walls. However, the story drift limit of FEMA 356 was satisfied for all buildings. Through the analysis of performance points, it was shown that the spectral acceleration has an inverse relationship with the natural period.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.1-11
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• 2024

The purpose of this paper is to suggest a method for applying a reasonable dam axial seismic load loading method and load-bearing capacity evaluation method in the dynamic analysis of the pier part of a concrete dam to which the seismic force of the collapse prevention level is applied. To this end, the pier part of a concrete dam was selected as a target facility, and the characteristics of the dynamic behavior in the axial direction of the weir dam were analyzed through dynamic analysis applying various weir widths, and 'U.S. The load-bearing capacity evaluation was performed by applying the RC hydraulic structure evaluation technique suggested by the Army Corps, 2007'. As a result of the study, when applying seismic force in the axial direction of the pier part, it is more realistic to assume that the axial direction of the weir part dam behaves as a rigid body and 'U.S. Army Corps, 2007' suggested that the method of reviewing the load-bearing capacity for moment and shear was considered reasonable, so it was concluded that improvement of the current evaluation method was necessary. If the improvement of the research result is applied, it will have the effect of deriving more reasonable evaluation results than the current seismic performance evaluation method using CLE. It is judged that additional research is needed in the future on the torsional moment occurring in the pier part.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.27-33
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• 2023

In a petrochemical plant, various mechanical equipments and structures are interconnected to ensure operability. Since the production activities of petrochemical plants have a great impact on the national economy, it is very important to maintain not only structural safety but also the operability of the facilities. However, the current seismic design standards present the design requirements of facilities mainly aimed at preventing collapse, and do not provide the requirements for securing operability of facilities. Depending on the behavioral characteristics of the facility, operability of the facility can be secured by seismic performance levels other than the collapse prevention level, so it is necessary to present seismic design methods that can apply various seismic performance levels. Spherical (ball) storage tanks are supported by columns and braces and exhibit complex nonlinear behavior because of buckling and yielding of support members. In this study, nonlinear seismic behavior characteristics were statistically analyzed and a new performance-based seismic design method was proposed based on them.

• Journal of the Korean GEO-environmental Society
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• v.13 no.2
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• pp.49-57
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• 2012

Large-scale collapse happened under excavation construction in the past. But, recently the trend that it is completed safely to minimize damages is growing because of increasing levels of design review and detecting signs of problems before the outbreak of large-scale collapse with proactive planning of measurement. In this paper, through studying case collapses over the past, it put the cause of the collapse in order. And then, after reviewing general information on management and utilization of measurement methods which importantly emerging recently, the type and cause of the problem during the excavation was reviewed. And the causes of problem were analyzed by targeting the site which unusual symptoms happened on measuring results under construction. In this study, the awareness that measurement management and subsurface investigation is highly important will increase for preventing large-scale collapse in advance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.785-791
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• 2023

Risk management is essential for preventing accidents arising from uncertainties in TBM tunnel projects, especially concerning managing the risk of TBM tunnel collapse, which can cause extensive damage from the tunnel face to the ground surface. In addition, prioritizing risks is necessary to allocate resources efficiently within time and cost constraints. Therefore, this study aimed to establish a TBM risk database through case studies of TBM accidents and determine a risk priority for TBM tunnel collapse using the Bayes theorem. The database consisted of 87 cases, dealing with three accidents and five geological sources. Applying the Bayes theorem to the database, it was found that fault zones and weak ground significantly increased the probability of tunnel collapse, while the other sources showed low correlations with collapse. Therefore, the risk priority for TBM tunnel collapse, considering geological sources, is as follows: 1) Fault zone, 2) Weak ground, 3) Mixed ground, 4) High in-situ stress, and 5) Expansive ground. In practice, the derived risk priority can serve as a valuable reference for risk management, enhancing the safety and efficiency of TBM construction. It provides guidance for developing appropriate countermeasure plans and allocating resources effectively to mitigate the risk of TBM tunnel collapse.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.6
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• pp.412-421
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• 2013

Nowadays, small and medium-sized earthquakes occur frequently in the west coast of Korea. The earthquake induced damages on the harbor structure such as quay wall possibly make a severe impact on national economy. Therefore, not only a seismic design for the structures but warning system for seismic damage right after the occurrence of earthquake should be developed. In this study, seismic fragility analysis was performed to be given to earthquake damage prediction system for quay wall structures in Busan and Incheon harbor. Four types of structures such as pier-type, caisson type, counterfort type, block-type were analyzed and fragility curves of functional performance level and collapse prevention level based on displacement criteria were found. Regression analyses by using the results of the two ports were done for possible use in other port structures.