• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.83-90
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• 2002

There are few earthquake records in Korea and the Japanese or American representative earthquake records have been generally used in the seismic design. In this study, some earthquake records which the range of earthquake magnitudes varies from 5.3 to 7.9 were collected and analyzed to assess which record can rationally reflect Korean seismic characteristics. In this assessment, each seismic energy and acceleration spectrum were analyzed with the unified maximum ground acceleration. Several numerical analyses on Korean representative caisson structures were also carried out to compare each dynamic displacement. In these numerical analyses, soil conditions and the dimension of structure such as height and width were changed. Through this assessment, it is found that the compatible earthquake magnitude in Korea is lower than 7. From the result of numerical analyses, it is shown that horizontal dynamic displacements corresponding to earthquake magnitudes over than 7 are quite larger than those below earthquake magnitude 7. Based on this study, it is necessary that Korean seismic design guideline will refer earthquake magnitude criteria for the construction of the economical aseismic structure.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.267-273
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• 2013

Early design phase energy modeling is used to provide the design team with first order of magnitude feedback about the impact of various building configurations. For better energy-conscious and sustainable building design and operation, the construction of BIM data interoperability for energy performance assessment in the early design phase is important. The purpose of this study is to suggest construction of BIM data interoperability for energy performance assessment based on BIM. To archive this purpose, the authors have investigated advantage of BIM-based energy performance assessment through comparison with traditional energy performance assessment and suggested requirement for construction of open BIM environment such as BIM data creation, BIM data software practical use, BIM data application and verification. In addition, the authors have suggested BIM data interoperability and BIM energy property mapping method focused on materials.

• Journal of the Korean Society of Safety
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• v.28 no.6
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• pp.64-72
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• 2013

Construction machinery has been utilized to carry out construction works effectively. Using construction machinery enables a builder to reduce the time and the cost needed for the construction, but the fatal accident caused by it has been increased. This study is intended to identify risk magnitude of accident by kind of construction machinery through interviews with experts. Construction machineries surveyed in this research are excavator, tower crane, lift, mobile crane and forklift, those are the machinery which accident occurs more often than the other machinery. To evaluate the risk of the accidents identified, risk category was determined according to the US DOD system safety program (MIL-STD-882B) considering the risk degree and intensity. As a result, accident occurred in the process of material transport & handling was found to be the most dangerous. On the other hand, the accidents caused by the defective machinery and the poor safety gear were considered to be less dangerous relatively. The risk category by type of construction machinery suggested in this study is expected to provide the basic data in developing the safety guidance for construction project.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.373-380
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• 1999

Consolidation settlements of soft clay are often large and potentially damaging to the structures. Currently, large-scale construction projects for airport and harbor etc. are in progress in Korea and many of these structures will be constructed on thick and soft clay layers. For this kind of ground condition, evaluation of consolidation settlement is required at every design and construction stages, and the magnitude of secondary compression appears to be larger than expected. Generally, the magnitude of secondary compression is evaluated by laboratory and in-situ consolidation tests or by empirical $C_{a/}$ $C_{c}$, relationship. The use of empirical value $C_{a/}$ $C_{c}$ may be economical, fast and powerful tool in estimating secondary consolidation settlement. However, the databases of the $C_{a/}$ $C_{c}$, for typical soft clays in Korea are insufficient. The purpose of this study is to investigate the relationship of $C_{a/}$ $C_{c}$ on marine clay near the southern sea in Korea. A series of incremental loading consolidation tests with measurement of pore water pressure were performed. It was found that the $C_{a/}$ $C_{c}$ of undisturbed marine clay is 0.0397. This value is similar to that proposed by Mesri and Castro(1987) on inorganic clay and silt. and silt. and silt.

• Earthquakes and Structures
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• v.9 no.2
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• pp.431-453
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• 2015

A destructive earthquake, the magnitude of this earthquake was 7.2, hit Van, Turkey on October 23, 2011. After this devastating earthquake, a moderate earthquake which had 5.7 magnitude on November 9, 2011 occurred in Edremit, Van. These earthquakes caused heavy damages and collapses in many reinforced concrete buildings with loss of lives. In this paper, characteristics of ground motions of these earthquakes were studied and, deficiencies in structural elements and engineering faults such as poor workmanship and quality of construction, soft and weak stories, strong beam-weak column, short column, large overhang, hammering and unconfined gable wall were investigated. According to the observations, it was seen that, low quality of structural materials, lack of engineering services, inappropriate design and construction with insufficient detailing of the structural elements were the main reasons of heavy damages.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.474-480
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• 2017

In this study, the evolution of electrical impedance of electric nodes was investigated to determine the setting time of cement paste using the electrical impedance spectroscopy method. The electric nodes were embedded in fresh cement paste and the electrical impedance signatures were continuously monitored. Vicat needle test and semi-adiabatic calorimetry test were also conducted to validate the electrical impedance spectroscopy method. During hydration period of cement paste, the magnitude of conductance gradually increased, and then started to decrease rapidly at a first certain time. After that, the magnitude of conductance gradually decreased at a second certain time. The times of turning point in the curves of magnitude of conductance seem to be related with the setting time by Vicat needle test. Also, the setting times by the electrical impedance spectroscopy method are well posed within the setting period estimated by the semi-adiabatic calorimetry test. Based on the results, it can be concluded that the setting time of cement paste can be effectively monitored through the electrical impedance spectroscopy method.

• Architectural research
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• v.10 no.1
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• pp.41-48
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• 2008

Construction projects have frequently exceeded their schedule despite reliable estimates at the start of a project. This problem was attributed to unpredictable causes at the beginning and to shortage of proper tools to accurately predict project completion date. To supplement this difficulty, project managers need a comprehensive system that can be employed to monitor the progress of an ongoing project and to evaluate potential delay for achieving the goal on time. This paper proposed a progressive-based expert system for quantitative assessments of project delay at the early stages of the execution. Furthermore, the system is used to inspect the change of the uncertainty on completion date and its magnitude. The proposed expert system is helpful for furnishing project managers a warning signal as a project is going behind schedule and for tracking the changed uncertainty at a desired confidence level. The main objectives of this paper are to offer a new system to overcome the difficulties of conventional forecasting tools and to apply a construction project into the system to illustrate its effectiveness. This paper focuses on construction phase of project development and is intended for the use by project managers.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.225-228
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• 2006

Fast construction of bridge structures is a new trend of bridge design. Accelerated bridge construction includes the construction of superstructures and substructures. In order to reduce the construction time for substructures, precast prestressed bridge piers are increasingly applied in other countries. One of the main concern in the design of precast piers is the determination of the axial prestress forces. The behavior of the piers should be investigated under service loadings and ultimate conditions. In this paper, the magnitude of prestress is calculated to control the stress at the joint of precast piers. Considering long-term behavior of prestressed piers, P-M diagrams for precast piers are obtained to verify the ultimate behavior of the piers. Based on these studies, precast piers are applied to the light-railway bridge piers.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.629-635
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• 2011

Retentions are generally considered to be intended to act as a powerful tool to incentivize contractors/subcontractors to remedy defective work in cases of non-performance. This study attempts to establish the extent to which retentions can be used for this purpose by investigating case law connected with insurance and defective work. One of the significant questions is whether retentions are sufficient to deal with construction defects or value of retentions in the rectification of defects is illusory. The cost to repair a defect may vary depending on a number of components including type, cause, magnitude and the construction stage at which the defect occurs. It is expected that a review of existing cases on defective workmanship will provide an insight on the issues and whether retentions are effective in their intended function. In order to establish their functionality, the study described in this paper investigated 6 construction insurance cases to identify the critical issues and the causes of dispute. It was found that the nature and the cause of defects were different in each case. It was also established that certain defect types not covered by insurance may be covered by retentions - potentially one of the key uses of a retention strategy. It is expected that the findings will assist in forming a view on the quantum of money that may be required paving the way for a first time understanding on a rational basis for setting up retention regime.

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.79-87
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• 2017

In this paper, for 43 sites neighboring to western area of Gangwondo where disaster of debris flow occurred from 2006 to 2013, magnitude of debris flow was estimated from results of site investigation and correlation analysis between influencing factors to its magnitude was performed. Magnitude of channelized debris flow was found greater by 6.5 times of that of hill slope debris flow and approximately 5% of total volume was occurred at initiation part of channelized debris flow. As results of analyzing yield rate of debris flow, for channelized debris flow, yield rate values of $19m^3/m$ and $8m^3/m$ were obtained for total volume being over $10,000m^3/m$ as the large scale of debris flow and less than $10,000m^3/m$ respectively, and value of $5m^3/m$ was estimated for hill slope debris flow. As results of correlation analysis of influencing factors to magnitude of debris flow, runoff distance and erosion width were very highly correlated to its magnitude whereas average slope of basin and erosion depth showed relatively low correlation. In particular, value of erosion depth was in the range of 0.5-2.6 m, being similar range to the value proposed by Ikeya (1981). Triggering rainfall to debris flow such as continuous rainfall and maximum intensity of hour rainfall were analyzed to have low correlation with magnitude of debris flow.