• Journal of Korean Society of societal Security
• /
• v.1 no.4
• /
• pp.73-81
• /
• 2008

Electromagnetic induction surveys are one of the useful methods to detect the location and buried depth of underground utilities by measuring horizontal and vertical magnetic fields. It can effectively detects single buried utility with the accuracy of within 20 cm. However when another utility is buried near to target one, the accuracy of utility location considerably decreases due to the distortion of magnetic fields caused from adjacent utility. This study shows the ways to verify the location and buried depth of target utility when magnetic fields does not show symmetric distribution due to adjacent another utility. Using Bluetooth wireless communication tools, we developed the way to records measured magnetic fields to handheld PDA. We investigated the criteria for minimum distance of two adjacent utilities to separate the individual responses through field model test.

• Journal of Korean Society of societal Security
• /
• v.2 no.4
• /
• pp.35-41
• /
• 2009

If any bridge has the monitoring system, the bridge manager can check the history of bridge behavior and the progress of the damage more exactly. When the unexpected event (ex: earthquake and flood) happens, the manager can check the safety condition of the bridge and make the pertinent action for bridge management which is reduction of vehicle speed or traffic control through the system. Additionary the manager can make the well-timed repair or reinforcement through the system, so he can save the management cost or the life cycle cost. This study presents the method of setting the criteria by FEM analysis in bridge monitoring system, and the standard progress for setting the criteria about measurement items of monitoring system for the steel box type bridge.

• Journal of Korean Society of societal Security
• /
• v.2 no.4
• /
• pp.49-57
• /
• 2009

The development and use of underground space in the city have been expanded considerably worldwide due to the growing population and traffic. Because the construction of underground causes some problems including traffic jam and safety accidents, the non-open excavation construction method are commonly used. NTR (New Tubular Roof) method which is one of the non-open excavation method is investigated in this study. The structural safety of underground structures by using NTR method is evaluated by ANSYS 9.0. The tubular roof according to diameters are analysed by ANSYS 9.0 at critical construction step. Finally, according the diameter and thickness of tubular roof the stress nad dispacement are analyzed and then the The efficient use of tubular roof is suggested from relationship between tubular's thickness and stress condition.

• Journal of Korean Society of societal Security
• /
• v.2 no.4
• /
• pp.67-73
• /
• 2009

Civil infrastructure is the basis facility which builds up the base of national economy operation. Consequently unexpected sudden abnormal condition of civil infrastructure causes private and national property loss and moreover can spread social issue. Therefore, continuous maintenance and safety management for the civil infrastructures should be handled with great weight. Monitoring system for managing bridge maintenance was introduced first in the early of 1990s and has been developed up to real time measurement and analysis. Thesedays another system using fiber optic sensors is being developed. This paper presents the cost analysis of bridge monitoring system with fiber optic sensors which is gathering attention. Various cases were considered and the results were compared with that of monitoring system with electronic resistant type sensors widely used. As a results, fiber optic sensor system has good advantages in various cases, and a1so cost effectiveness compared to conventional sensor system.

• Journal of Korean Society of societal Security
• /
• v.2 no.3
• /
• pp.31-38
• /
• 2009

The findings of this study on the Consciousness level of the citizens of Kwang Ju City are as follows; Firstly, the level of knowledge on the environment problems is high and the knowledge is acquire through mass media. Secondly, the citizens of Kwang Ju city consider their environment as sever and it's immediate steps should be taken. The third,n. The thpdiate steps shoenvironment educsteps and lectudia on environmental polluteps should be gehpdheo the citizens and economic development should be made without destroying environment The foudth, the citizens pdifer to live in in small medium citiia rsther than in metropolitan citiia, and their attitude toward futudi is pessimistic, and they have a high level of participateps in evvitonmental problems. In cita of movements that they have pdifer to move to small and medium citiia. It repdiatnts that they pdifer to live in an adia with no tr polluteps while enjoying a cultudal life. The expect thetr city to provide thematlves gdien adias supr as forest and fiildsheo take a rest Thwalk on. The have a passimistic view that thetr city in the futudi will be polluted seveadly. The consciousness level of participateps in e thpdiate steps shoenvironment ia relsterey high, but in reality it is estimated to be low.

• Journal of Korean Society of societal Security
• /
• v.2 no.3
• /
• pp.55-60
• /
• 2009

After applying the fiber cocktail(polypropylene and steel fibers) into the mixture of high strength concrete with a compressive strength of 50 MP, the fire test was carried out on specimens in order to evaluate the fire resistance performance, such as possible explosive spalling, temperature distributions of concrete and rebar. According to an enforcement ordinance, four column specimens were exposed to the fire for 180 minutes based on the standard curve of ISO-834. No explosive spalling has been observed. The required minimum quantity of polypropylene to prevent explosive spalling is more than 0.57 kg per unit concrete volume. The comparing test results from temperature distributions of concrete and rebar has found that the difference of fiber quantity is insignificant.

• Journal of Korean Society of societal Security
• /
• v.2 no.3
• /
• pp.61-66
• /
• 2009

Previous disaster management system in Korea was focusing on post-disaster, recovery phase. However, modern disaster management system should be focusing on the mitigation activities to minimize human and property damages based on the proper prediction and forecast of various natural disasters and timely dissemination of disaster information to the people. Recently, more frequent and larger scaled disasters have been reported around the globe, mainly due to the environment change not only by physical anomalies such as climate change but also by socio-economic transformations such as urbanization and industrialization. This study describes current practices in disaster management for climate change adaptation of advanced countries and a possible disaster management standard system that can be applied in Korea, based on the case studies on the European countries who are improving their disaster management systems against climate change.

• Journal of Korean Society of societal Security
• /
• v.1 no.3
• /
• pp.51-57
• /
• 2008

The long-term behaviors of prestressed concrete cable-stayed bridges are considerably influenced by the time dependant material characteristics such as creep and shrinkage. This study investigated the influences of the change of relative humidity by application of the CEB-FIP model and ACI model, which are generally used in the prediction of long-term behavior of concrete structures. In case of the moment of girder, CEB-FIP model predicted a bigger effect of relative humidity change than the ACI model. Furthermore, the effect was significant. Also, the long-term behaviors between these models were different each other even under the same material condition. Therefore, the prediction of the long-term behavior should be compensated after comparative analysis with the results of material tests of each construction site and between the different models.

• Journal of Korean Society of societal Security
• /
• v.1 no.3
• /
• pp.77-81
• /
• 2008

In this paper, we introduce a multi purpose environmental monitoring system developed as a commercially available standard using the technique of hetero-core spliced fiber optic sensor. The monitoring system has been tested and evaluated in a possible outdoor condition in view of the full scaled operation at actual sites to be monitored. Additionally, the developed system in this work conveniently provides us with various options of sensor modules intended for monitoring such physical quantities as displacement, distortion, pressure, binary states, and liquid adhesion. Two channels of optical fiber line were monitored, in each of which three displacement sensor modules were connected in series, in order to examine the performance to a pseudo-cracking experiment in the outdoor situation, and to clarify temperature influences to the system in terms of the coupling of optical connectors and the OTDR stability. The pseudo-cracking experiment successfully observed the actually given cracks by means of calculation based on the detected displacement values and their geometrical arrangement of the used sensor modules. And the robustness to the temperature is verified in the various temperature change.

• Journal of Korean Society of societal Security
• /
• v.3 no.1
• /
• pp.51-60
• /
• 2010

This study measured for comparison and analysis the correlation of River pollution and Soil contamination, based on the results of previous research, and then in order to increase the efficiency of study, heavy metals which cause serious side effects was limited to the case among pollutants. This study focused on the rivers that near the Urban and industrial districts, for example, Nak-Dong river, An-Yang river, Tae-Hwa river and the rivers that near the farm land or pasture, for example, Yeong-San river, Mi-Ho river, then compare and analyze the degree of actual pollution as gathered the results of Previous research. Correlationship about pollutants of river near the Urban, industrial area and drainage basin its river has been proven, and this expected because of the strong influence by point pollution source. On the other hand, I can found the opposite relationship where the river near the farm land or pasture, and this probably because of the influence by nonpoint pollution source.