• Journal of Korean Society of Disaster and Security
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• v.15 no.3
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• pp.67-77
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• 2022

In South Korea, U-type girder development was attempted as a means to increase the length of I-type girder, but due to the large self-weight according to the post-tension method, the application of rail bridges of 30m or less is typical. There are not many examples of application of pre-tension type girder. This study does not limit the post-tension method, but applies the pre-tension method to induce a reduction in self-weight and materials used due to the reduction of the cross-section. In addition, we intend to apply the on-site pre-tensioning method using the internal reaction arm of the U-type girder. The prestressed concrete U-type girder bridge is composed of a concrete deck slab and a composite section. Compared to the PSC I-type, which is an open cross-section because the cross section is closed, structural performance such as resistance and rigidity is improved, the safety of construction is increased during the manufacturing and erection stage, and the height ratio is reduced due to the reduction of its own weight. Therefore, it is possible to secure the aesthetic scenery and economical of the bridge. As a result, it is expected that efficient construction will be possible with high-quality factory-manufactured members and cast-in-place members. In this paper, the introduction of the pre-tension method on-site and the analytical performance verification of the anchoring block for tension are included.

• Journal of the Korean Society of Safety
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• v.35 no.4
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• pp.23-31
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• 2020

In the construction sector, there were 99 fatalities from falls associated with steel tube and system scaffolds for three years from 2016 to 2018 and out of which 27.3 percent (27 workers) were found to have occurred during installing and dismantling procedure. To erect scaffolding which is installed for the work at height, the work platforms are generally installed first and the safety guardrails are installed and vice versa to dismantle. As a result, workers are exposed to the risk of falling because they erect and dismantle scaffolding without guardrails. To minimize the risk of falling, it is necessary to study a new construction method that can erect or dismantle scaffolding while guardrails are installed (called advanced guardrail system). This study analyzed advanced guardrail system in terms of safety regulation, workability and economic efficiency by investigating the domestic situation on the use of scaffolding, reviewing domestic and foreign standards for guardrails and conducting economic feasibility study. The results of this study is expected to greatly contribute to preventing falls in scaffolding installation and dismantlement procedure. As a follow-up study, empirical research is required including physical test of scaffolding with advanced guardrail system and effectiveness analysis after trial applications.

• Journal of architectural history
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• v.8 no.3 s.20
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• pp.9-22
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• 1999

The purpose of this study is to analyse the architectural character of JE-DAMG at farm village in Ulsan. JE-DANG means the building for DONG-JE (the sacrificial rite of a village). The regions of this study are KANG-DONG MYEN, and UNG-CHON MYEN in Ulsan. The method of this study is the analysis of them after the actual field surveys of 47 JE-DANGs in these regions The survey contains the area, the height, the period of the erection, the architectural structure, the roof shape, the material, the landowner, SHIN-CHE (means a god's name and shape), DANG-SU tree and so on. Methods of the survey are the field survey, the interview of villager, the analysis of reference data and so on. Results of the study are below. JE-DANGs(buildings) of these regions had been built first in the period of Japanese occupancy and erections of them had continued until 1970's. Since then, they have been rebuilt. The primary JE-DANG is characterized by a tiled roof, a wooden post lintel, a mud-plastered wall, and a wooden door. After rebuilding, characters are a flat slab, a tiled roof, a structure of using red bricks, and the area is getting larger than the primary JE-DANG, but 1 KAN persists without variety. Most of houses in the inland area like UNG-CHON MYEN face the south, and ones in the coastal area like KANG-BONG MYEN face the east. Generally there is DANG-SU tree behind JE-DANG. That proves DANG-SU tree to be the object of the rite. The species of DANG-SU is a pine in general ,but various in UNG-CHON MYEN. In general names of the god are DONG-SHIN , DANG-SAN SHIN and SUNG-HWANG SHIN. I think that the landownership of JE-DANG should change the private ownership into the village ownership to preserve JE-DANG though most of lands of JE-DANG are private ones.

• Journal of the Korea Society of Computer and Information
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• v.12 no.3
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• pp.225-234
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• 2007

This research is based on the purpose of awaking the importance to publicity of terrorism prevention in the environment of neo-terrorism and presenting the direction of effective publicity activities of terrorism prevention in the counter-terrorism system. Government publicity through public media plays a significant role in promoting people's participation and improving the awareness. So, to strengthen the terrorism prevention in environmental changes of terror occurrence, active method available for people must be found as publicity method of terrorism prevention suitable for high information society. For this method, this research argued first about relationship between police organization and public as counter-terrorism system and about effective publicity methods of terrorism prevention through active erection of these relationships. This research suggested the operation method through introduction of e-CRM and etc, with ultimate purpose about maximizing the publicity effect of terrorism prevention by using as the advantage of internet these days as possible. And needs of information service activities and other administration strategies of publicity of terrorism prevention are suggested through enlarging the distribution scope of governmental counter-terrorism information materials by strengthening the national publicity activities and using media.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.577-585
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• 2023

Lateral torsional buckling causessafety accidentssuch as collapse accidents during erection. Therefore, anaccurate safety designshould be conducted. Lateral torsional buckling canbe prevented by reinforcing the end orreducing the unbraced length. The method ofreducing the unbraced length by installing a crossframe has high material and installation costs and low maintenance performance.In addition, structuralsafety may be deteriorated due to cracks. The end reinforcement method using Concrete Filled Half Pipe Stiffeneris a method ofreinforcing the end of a plate girder using a stiffenerin the form of a semi-circular column. This method increasesthewarping strength ofthe girder and increasesthe lateral torsional buckling strength.In thisstudy, the effect ofincreasing the warping strengthof plate girders with concrete filled half pipe stiffeners was confirmed. To verify the effect, the results ofthe designequationand the finite element analysis were compared and verified through a experiment. As a result, the plate girderwithCFHPS increased thewarping strengthand confirmed that the lateral torsional buckling strength was increased.

• Journal of Environmental Science International
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• v.5 no.5
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• pp.561-567
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• 1996

A method for the simultaneous analysis of 31 residual organic chloride pesticides was studied using gas chromatography. Prepared analytical samples were injected to gas chromatography (HP 5890 Series II plus) on the Ultra-2 column with ECD. The packing materials for column were changed as the following reagents ; florisil and alumina N, The residual solution was loaded to column and was elected pith erection solvents ; ether : benzene (2 : 8) solution, hexane : benzene (1 : 1) solution, dichloromethane, acetone, and methanol. The analytical results showed that 6 kinds of organic chlorides were not detected when florisil (first condition) was used as the column packing material. The nondetected 6 kinds of organic chlorides in the first analytical condition were detected and the recoveries of thrin-pesticides were increased, in particular, captan and captafol, but the recoveries of benzene hexachloride compounds were decreased when dichloromethane and methanol were added as elution solvents (pac'king material was florisil as in the first condition). The recoveries of dichlornuanid, chlorofenvinfos, folpet, and dicofol were increased and that of aldrin was increased, but those of captan and captafol were not good when alumina N was used as the packing material. To detect simultaneously thrin-pesticides, captan, and captafol, florisil and alumina N were used as the packing materials. The elution result showed that captan and captafol were not detected. This was because the column was activated insufficiently. The analytical method was the best (31 kinds of organic chlorides in the residual pesticides were detected sharply and showed high sensitivity) when the column (packing materials were florisil and alumina N: together) was fuliy activated and the impurities were removed using various elution solvents.

• Korean Journal of Heritage: History & Science
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• v.40
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• pp.105-135
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• 2007

Since now, the study of wooden pagodas in ancient Korea have been proceeded to the site plan, the devices and the goods of sarari containers and the reconstruction. They are based on the result of archaeological excavations and the historical material documents. But the study of the foundations of wooden pagodas have been unsatisfactory. In this paper, the investigations of the wooden pagodas in the Three Kingdoms are proceeded. Through this action, we have checked the method of the foundations, the type and installation of Simchoseok(central base stone) and the erection of Simju(central base pillar). In the result of this study, three types were in the method of the foundations-the construction of the upper on the surface of the earth, the construction of the upper and lower on the surface of the earth. And we know the types of the installation of Simchoseok were the underground-type central base stone and the ground-type central base stoned. The factors of the central base pillars were changed with the rising of central base stones from the lower on the surface of the earth to the surface of the foundation. This change was needed to construct the larger wooden pagodas than the ones of the past. In especially, the large wooden pagodas with the ground-type central base stoned were appeared in the king of Baekje, Muwang(A.D. 600~640). We assume that the method of the construction of larger wooden pagodas like that was forwarded to Silla and Japan.

• Journal of Korean Society of Steel Construction
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• v.23 no.3
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• pp.261-273
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• 2011

Recently, the demands for steel frame are increasing because of the trend and due to the demand for bigger and higher buildings. In the analysis of typical steel frame, connections are based on the idealized fixed or pinned connection. A fixed connection assumes that the relative angle of each member before deformation is the same after the transformation. Therefore, the stiffener reinforces the connection to sufficient rigidity and stability of the panel zone. In the economical aspect, however, the necessity of connection that the stiffener reinforcement has omitted is increasing due to the excessive production as well as labor costs of connection. In contrast, pinned connection is assumed that bending moments between the beams and columns do not transfer to each member. This is easy to make in the plant and the construction is simple. However, the structural efficiency is reduced in pinned connection because connection cannot transfer moments. The introduction of this semirigid process can decide efficient cross-sectional dimensions that promote ease in the course of structural erection, as performed by members in the field-a call for safety in the entire frame. Therefore, foreign countries exert efforts to study the practical behavior and the results are applied to criterion. This paper analyzes the semirigid connection of domestic steel by design specifications of AISC/LRFD and make data bank that pertain to each steel. After wards, the results are compared to those of idealized connection; at the same time, this paper presents a design method that matches economic efficiency, end-fixity, and rotational stiffness.

• Journal of Korean Society of Steel Construction
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• v.10 no.3 s.36
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• pp.553-564
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• 1998

Recently, more and more steel-deck structural system for two story roads has been adopted as a solution against traffic congestion in urban area, mainly because of fast construction, reduced self-weight, higher stiffness and efficient erection compared to that of concrete decks. The main objective is to study on the unit-elective optimal type and proportioning of a rational steel-deck system for two story roads using an optimum design program specifically developed for steel-deck systems. The objective function for the optimization is formulated as a minimum cost design problem. The behavior and design constraints are formulated based on the ASD(Allowable Stress Design) criteria of the Korean Bridge Design Code. The optimum design program developed in this study consists of two steps - the first step for the optimization of the steel box or plate girder viaducts, and the second step for the optimum design of the steel-decks with closed or open ribs. A grid model is used as a structural analysis model for the optimization of the main girder system, while the analysis of the deck system is based on the Pelican-Esslinger method. The SQP(Sequential Quadratic Programming) is used as the optimization technique for the constrained optimization problem. By using a set of application examples, the rational type related to the optimized steel-deck system designs is investigated by comparing the cost effectiveness of each type. Based on the results of the investigation it may be concluded that the optimal linear box girder and deck system with closed ribs may be utilized as one of the most rational and economical viaducts in the construction of two-story roads.

• Journal of Korean Society of Steel Construction
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• v.20 no.5
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• pp.633-644
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• 2008

The structural framework design uses high-strength bolts and welding in column splices. However, for the column under high compression, the number of the required high-strength bolts can be excessive and the increase of welding results in difficulty of quality inspection, the transformation of the structural steels, and the increase of erection time. According to the AISC criteria, when columns have bearing plates, or they are finished to bear at splices, there shall be sufficient connections to hold all parts securely in place. The Korean standard sets the maximum 25% of the load as criteria. Using direct contact makes it possible to transfer all compressive force through it. The objective of this study is to examine the generally applied stress path mechanism of welded or bolted columns and to verify the bending moment and compression transfer mechanism of the column splice according to metal touch precision. For this study,22 specimens of various geometric shapes were constructed according to the change in the variables for each column splice type, which includes the splice method, gap width, gap axis, presence or absence of splice material, and connector type. The results show that the application of each splice can be improved through the examination of the stress path mechanism upon metal contact. Moreover, the revision of the relative local code on direct contact needs to be reviewed properly for the economics and efficiency of the splices.