• Journal of Korean Society of Rural Planning
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• v.28 no.2
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• pp.11-20
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• 2022

As a portal to rural town, Myeon near large cities is expected to represent image of the rural area. But, the landscape are changing rapidly due to development pressure and to the expansion of the transportation network. For visitors and transit traffic, Recognizing that the characteristics of the streetscape is an important task for the vitalization of the rural district. In particular, it was found that the visual quantity of the central street in the location of the town was closely related to the preference of the streetscape, and the visual quantity of trees and the visual quantity of the building showed an inverse relationship of + and - respectively. Since this is not a simple ratio of the sky to the building, but a relative factor, the possibility of landscape improvement can be improved through management of public facilities or green spaces and maintenance of open spaces or gaps between buildings. It seems that it is necessary to secure separate means for the management of the architectural landscape, such as the establishment of a special landscape plan or establishment of ordinances.

• Structural Monitoring and Maintenance
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• v.9 no.2
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• pp.107-127
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• 2022

Structural health monitoring (SHM) has been related to damage identification with either operational loads or other environmental loading playing a significant complimentary role in terms of structural safety. In this study, a non-parametric method of time frequency analysis on the measurement is used to address the time-frequency representation for modal parameter estimation and system damage identification of structure. The method employs the wavelet decomposition of dynamic data by using the modified complex Morlet wavelet with variable central frequency (MCMW+VCF). Through detail discussion on the selection of model parameter in wavelet analysis, the method is applied to study the dynamic response of both steel structure and reinforced concrete frame under white noise excitation as well as earthquake excitation from shaking table test. Application of the method to building earthquake response measurement is also examined. It is shown that by using the spectrogram generated from MCMW+VCF method, with suitable selected model parameter, one can clearly identify the time-varying modal frequency of the reinforced concrete structure under earthquake excitation. Discussions on the advantages and disadvantages of the method through field experiments are also presented.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.63-64
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• 2020

The purpose of this study is to find out how construction sites workers experience adaptation processes in relation to the prevention of safety accidents in the workplace through the method of grounded theory. In order to understand the experience of preventing safety accidents of workers at construction sites, a grounded theory analysis method was chosen. In order to achieve the purpose of this study, the first questionnaire was sent to 17 people working in the construction site by e-mail, and the participants of the study were met one by one for in-depth interviews. As a result of this study, the paradigm model of the experience of preventing safety accidents of workers at construction sites was classified into causal conditions, contextual conditions, central phenomena, intervening conditions, action/interactions, and outcomes. The conclusions of this study are as follows. First, forming a safety culture that can improve the safety awareness of construction sites is a priority. Second, it is necessary to improve self-management capabilities so that construction workers can accurately diagnose their current state such as their own body, emotion, and cognition and provide appropriate safety education. Third, providing safety education for construction workers with negative thoughts or distorted beliefs about safety accidents needs to include psychological treatment and counseling, such as methods of emotional purification, methods of relieving and managing stress, and methods of removing trauma.

• Journal of the Korea Institute of Building Construction
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• v.23 no.1
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• pp.81-92
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• 2023

According to the 2020 industrial accident reports of the Ministry of Employment and Labor, the number of fatal accidents in the construction industry over the past 5 years has been higher than in other industries. Of these more than 50% of fatal accidents are initially caused by fall accidents. The central government is intensively managing falling/jamming protection device and the use of personal protective equipment to eradicate the inappropriate factors disrupting safety at construction sites. In addition, although efforts have been made to prevent safety accidents with the proposal of the Special Act on Construction Safety, fatalities on construction sites are constantly occurring. Therefore, this study developed a model that automatically detects the wearing state of the worker's safety helmet and belt using computer vision technology. In considerations of conditions occurring at construction sites, we suggest an optimization method, which has been verified in terms of the accuracy and operation speed of the proposed model. As a result, it is possible to improve the efficiency of inspection and patrol by construction site managers, which is expected to contribute to reinforcing competency of safety management.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.436-442
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• 2022

Hurricanes and tornadoes are the most destructive natural disasters in some central and southern states. Thus, storm shelters, which can provide emergency protections for low-rise building residents, are becoming popular nowadays. Both FEMA and ICC have published a series of manuals on storm shelter design. However, the authors found that the materials for related products in the market are heavyweight and hard to deliver and install; renovations are necessary. The authors' previous studies found that lightweight and high-performance composite materials can withstand extreme wind pressure, but some building codes are designated in wind-borne debris areas. In these areas, wind debris can reach greater than 100 mph speed. In addition, the impact damage on the composite materials is an increasing safety issue in many engineering fields; some can cause catastrophic results. Therefore, studying composite structures subjected to wind debris impact is essential. The finite element models are set up using the software Abaqus 2.0 to conduct the simulations to observe the impact resistance behavior of the carbon fiber composite sandwich panels. The selected wood debris models meet the FEMA requirements. The outcome of this study is then employed in future lab tests and compared with other material models.

• Journal of the Korea Institute of Building Construction
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• v.23 no.5
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• pp.519-526
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• 2023

This research endeavors to explore the nuances in apparent resistivity readings in concrete specimens due to the proximity of embedded reinforcement. To systematically gauge this, concrete samples incorporating singular and paired rebars were meticulously crafted. These rebars were strategically positioned at intervals of 0.03m, 0.04m, and 0.05m from each specimen's midpoint. Subsequent resistivity assessments were conducted at 0.01m increments up to the predetermined rebar location for each sample. A consistent observation was the nadir in apparent resistivity manifesting at the rebar's epicenter. Notably, dual-rebar configurations registered lower resistivity values at this central juncture compared to their single-rebar counterparts. This metric underscores the palpable impact of surrounding reinforcement on resistivity readings. Further, as the spatial separation between rebars increased, the distinctness in their locational identification via resistivity became increasingly pronounced.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.143-144
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• 2023

The compressive strength of concrete varies depending on various factors. Among them, based on the curing temperature, the KCS 14 20 10 Standard Specification for General Concrete calculates the nominal strength by applying the temperature correction value (Tn) based on the compressive strength of the standard cured concrete at 20±2℃ when designing the formulation strength. However, Tn is a correction value that considers only the temperature, and the correction of strength difference due to heat of hydration is not applied. Therefore, in this study, one-component and two-component concrete are mixed in the summer, structural concrete are manufactured, standard concrete specimen are manufactured, and coring is performed on the central and boundary parts of the structural concrete to calculate the correction value applied to the nominal strength by comparing the compressive strength of standard cured concrete on the 28th day of curing and the compressive strength of structural concrete on the 91st day of curing.

• Geomechanics and Engineering
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• v.37 no.6
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• pp.565-576
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• 2024

In this study, the earthquake risk assessment of single-story RC precast buildings in Turkey was carried out using loss curves. In this regard, Kocaeli, a seismically active city in the Marmara region, and this building class, which is preferred intensively, were considered. Quality and period parameters were defined based on structural and geometric properties. Depending on these parameters, nine main sub-classes were defined to represent the building stock in the region. First, considering the mean fragility curves and four different central damage ratio models, vulnerability curves for each sub-class were computed as a function of spectral acceleration. Then, probabilistic seismic hazard analyses were performed for stiff and soft soil conditions for different earthquake probabilities of exceedance in 50 years. In the last step, 90 loss curves were derived based on vulnerability and hazard results. Within the scope of the study, the comparative parametric evaluations for three different earthquake intensity levels showed that the structural damage ratio values for nine sub-classes changed significantly. In addition, the quality parameter was found to be more effective on a structure's damage state than the period parameter. It is evident that since loss curves allow direct loss ratio calculation for any hazard level without needing seismic hazard and damage analysis, they are considered essential tools in rapid earthquake risk estimation and mitigation initiatives.

• Structural Engineering and Mechanics
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• v.89 no.6
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• pp.627-634
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• 2024

This research deals with the process of conducting a reinforced concrete slab loading test of a Residential Complex Project at the Shatt Al Arab District which is located in southern Iraq. The purpose of the test which represents a destructive test is to evaluate the structural behavior of the slab condition state during and after the examination of the test process in order to ascertain the ability of the slab ceiling to withstand the loads generated during the use of the building. The test was carried out accordant to ACI 437.2-13 code. The reason for this test is the postponed 8 years of building project construction. Concrete blocks were used to simulate and conduct a loading test of 30-tons for 3 days. The central point has been installed to measure the slab deflection that occurred during the test. The results showed that both the total deflection and residual deflections were lesser than the permissible values according to the ACI 437.2-13, the RC slab behavior was mainly linear structural behave, and that the purpose of the examination was achieved. Finally, a new method was introduced to the assessment of the slab condition at the support which is found in good condition.

• Journal of Korean Society of Archives and Records Management
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• v.3 no.1
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• pp.159-184
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• 2003

In this research the issues of record management of national archives in Korea are classified into four categories: 1) improving the status of the Central Archives of Korea, 2) constructing a new national archives, 3) revising the law on the record management, 4) creating qualifications for a professional administrator for Archivist. 1) In order to strengthen the function of the Central Archives of Korea, it is very urgent to create a systematic mechanism in which the Central Archives oversees and administers public archives(documents) collected from all the public institutions not only under the Administration but also the legislature and the judicial authorities. 2) This paper suggests that a new National Archives should be a symbolic building representing Korea as archives. Considering the fact that Presidents archives will be a part of this new National Archives, it also suggests that artistic and decorative pieces which embody Korea's representative archives or people should be included in the building. The budget for these should be supplied by the government. 3) This paper looks at the matter of revising the law on Record Management in two respects: (1)strengthening the function of the Central Archives of Korea, (2)making it obligatory to produce archives not open to the public, or making a protection clause for secret archives. This paper proposes that the Central Archives of Korea will be able to collect all the public archives from all the public institutions, and to oversee and administer them by revising the 5th and 6th clauses of the current law on the record management. It also proposes that some laws which make it obligatory to produce archives for documents not open to the public, and which protect those secrecy. 4) Regarding the qualifications for a professional administrator for the record management, this paper suggests lowering the qualification a little to the bachelor's degree of the record management. Also it suggests taking into consideration the persons in charge of the record management in public institutions and acknowledging their qualifications after a certain period of training at the Central Archives of Korea or something like that. In addition, it classifies the ranks of the professional administrators according to their qualifications.