• Journal of the Korea institute for structural maintenance and inspection
• /
• v.27 no.6
• /
• pp.102-110
• /
• 2023

PSC-I girder bridges constitute the largest proportion among highway bridges in Korea. According to the precision safety diagnosis data for the past 10 years, approximately 41.3% of the PSC-I bridges have been graded as C. Furthermore, with the increase in the aging of bridges, preemptive management is becoming more important. Damage and deterioration to the deck and girder with a long replacement cylce can have considerable impacts on the service and deterioration of a bridge. In addition, the high rate of device damages, including expansion joints and bearings, necessitates an investigation into the influence of the device damage in the structural members of the bridge. Therefore, this study defined representative PSC-I girder bridges with single and multiple spans to evaluate heterogeneous damages that incorporate the damage of the bridge member and device with the deterioration of the deck. The heterogeneous damages increased a crack area ratio compared to the individual single damage. For the single-span bridge, the occurrence of bearing damage leads to the spread of crack distribution in the girder, and in the case of multi-span bridges, expansion joint damage leads to the spread of crack distribution in the deck. The research underscores that bridge devices, when damaged, can cause subsequent secondary damage due to improper repair and replacement, which emphasizes the need for continuous observation and responsive action to the damages of the main devices.

• Journal of the Korean GEO-environmental Society
• /
• v.16 no.4
• /
• pp.5-12
• /
• 2015

Civil engineers have taken the numerous slope monitoring data for an engineering project subjected to hazard potential of slide. However, the topics on how to deal with and draw out proper information from the data related to the slope behavior have not been widely discussed. Recently, several researchers had installed the real-time monitoring system to cope with slope failure; however they are mainly focused on the hardware system installation. Therefore, this study tries to show how the measured data could be grouped and connected each other. The basic idea of analyzing method studied in this paper came from the clustering, which is the part of data mining analysis. Therefore, at the base of classification of time series data, the authors suggest three mathematical data analyzing methods; Average Index of different displacement ($AD_{i,j}$), Difference of average relative displacement ($\overline{RD}_{i,j}$) and Coordinate system of average and relative displacement ($\overline{RD}$, AD). These analyzing methods are based on the statistical method and failure mechanism of slope. Therefore they showed clustering relationships of the similar parts of the slope which makes the same sliding mechanism.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.23 no.1
• /
• pp.153-166
• /
• 2024

The digitalization of tasks for smart construction requires the smooth exchange of digital data among stakeholders to be effective, but there is a lack of digital data standardization and utilization methods. This paper proposes a digital construction information structure to transform information from road construction sites into digital formats. The study targets include significant tasks, such as work planning, scheduling, safety management, and quality control. The key to the construction information structure is separating construction information into objects and activities, defining unit works by combining these two types of information to ensure flexibility in representing and modifying construction information. The objects and activities have their respective hierarchical structures, which are defined flexibly to match the actual content. This structure achieves both efficiency and detail. The pilot structure was applied to highway construction projects and implemented digitally using general formats. This study enables the digitalization of road construction processes that closely resemble reality, accelerating the digital transformation of the civil engineering industry by developing a digital twin of the entire road construction lifecycle.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.28 no.2
• /
• pp.53-60
• /
• 2024

Prestressed concrete (PSC) bridges are vulnerable to corrosion and fracture of tendons, and in particular, structures using the internal post-tensioned with grouted system have difficulties in maintenance due to limitations of inspection. In this study, the actual behavior of PSC I girder bridge was analyzed according to tendon damage. The target PSC I girder bridge, an decommissioned highway bridge of upper and lower bridges, had the service period of 33 years and 20 years, respectively. Deflection and concrete strain were measured according to the location of damaged tendon and loading method. Regardless of the age of the bridge, its structural performance decreased when the damaged tendon was closer to the center of the girder. The change in behavior increased as the truck load approached to the girder where the tendon cut. If the load was applied to the adjacent girder where the tendon was cut, the structural performance was likely to be maintained due to the influence of the entire structural system. The change in deflection was difficult to observe visually, while the concrete strain exceeded the cracking strain. Therefore, it is recommended that future monitoring and inspection of PSC I girder bridges should focus on concrete strain or cracking.

• International Journal of Highway Engineering
• /
• v.13 no.3
• /
• pp.21-30
• /
• 2011

As well known, dowel bars are used to transfer traffic load acting on one edge to another edge of concrete slab in concrete pavement system. The dowel bars widely used in South Korea are round shape steel bar and they shows satisfactory performance under bending stress which is developed by repetitive traffic loading and environment loading. However, they are not invulnerable to erosion that may be caused by moisture from masonry joint or bottom of the pavement system. Especially, the erosion could rapidly progress with saline to prevent frost of snow in winter time. The problem under this circumstance is that the erosion not only drops strength of the steel dower bar but also comes with volume expansion of the steel dowel bar which can reduce load transferring efficiency of the steel dowel bar. To avoid this erosion problem in reasonable expenses, dowers bars with various materials are being developed. Fiber reinforced plastic(FRP) dower that is presented in this paper is suggested as an alternative of the steel dowel bar and it shows competitive resistance against erosion and tensile stress. The FRP dowel bar is developed in tube shape and is filled with high strength no shrinkage. Several slab thickness designs with the FRP dowel bars are performed by evaluating bearing stress between the dowel bar and concrete slab. To calculated the bearing stresses, theoretical formulation and finite element method(FEM) are utilized with material properties measured from laboratory tests. The results show that both FRP tube dowel bars with diameters of 32mm and 40mm satisfy bearing stress requirement for dowel bars. Also, with consideration that lean concrete is typical material to support concrete slab in South Korea, which means low load transfer efficiency and, therefore, low bearing stress, the FRP tube dowel bar can be used as a replacement of round shape steel bar.

• Korean Journal of Environment and Ecology
• /
• v.26 no.5
• /
• pp.730-740
• /
• 2012

Korea Expressway Corporation have a plan to make a new highway from East Hongcheon to Yanayang in Kangwon-do(province). This research was conducted to analyze a vegetation structure of japanese red pine forest and to prepare conservation and restoration basic information for minimizing the effects on pine mushroom producing by road construction. Considering the range of effects by road construction, twenty plots were set up near road construction reserved area, and surveyed. The result analyzed by TWINSPAN, one of the classification technique, showed that the communities were divided into four groups which are two Pinus densiflora community, Pinus densiflora-Quercus variabilis community and Pinus densiflora-Deciduous broad leaves forest community(IV). Species diversity index of each community ranged from $1.7353{\pm}0.0341$ to $1.9079{\pm}0.2471$, and the average number of species was $9.2{\pm}2.8$, especially $9.6{\pm}5.0$ at canopy layer in the unit area($100m^2$). The number of individuals ranged from 4 to 29 and average 9.55 in the unit area($100m^2$). The average RSI(relative space index) was below 35%, the average estimated age of the forest was $38{\pm}8.34$ years. The depth of $A_0$ layer of soil was 4~6cm and the range of soil acidity was pH4.70~5.63(average pH 5.29). Pine mushroom and Japanes red pine have a close symbiosis relation. Therefore it is needed that minimizing the read construction which goes through the pine mushroom producing area. If a road goes through a pine mushroom producing area, restoration measurement is prepared to prevent forest from rapid change such as succession or vegetation structure.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.5
• /
• pp.2049-2056
• /
• 2013

With the advance in information communication, the information age has come, and desire of human being in increasing. In this circumstance, the necessity for design for building of superhighways is arising to improve the mobility in the field of transportation, too. This study was conducted to analyze if driver can drive at a design speed on a superhighway with a design speed exceeding 120km/h. For this study, it was experimented if the running speed that makes a driver feel anxious, increased, when road alignment and standard improved, due to the differences of design speed. For the experiment, 30 subjects were asked to attach brain wave analyzers to bodies. Then, this study compared powers of ${\beta}$ waves generated, when they felt anxious, driving on the roads with different design speeds, and driving virtually through a simulator. Here, Kangbyeonbukro (90km/h), Jayuro(100km/h), Joongang Expressway(110km/h), and Seohaean Expressway(120km/h) were selected as experimental sections. While drivers drove on the Kangbyeonbukro and Jayuro at a speed of 80km/h - 130km/h, on the Joongang Expressway at a speed of 100km/h - 150km/h, and Seohaean Expressway at a speed of 110km/h - 180km/h, powers of anxiety EEGs(electroencephalogram) were compared, and during the simulation driving at the same speed of 110km/h - 180km/h, powers of anxiety EEGs were compared and analyzed. Moreover, the speed when anxiety EEGs increased, was statistically verified through paired t-test. As the result, the speed when anxiety EEGs increased during the simulation driving was nearly 30km/h higher than when they increased during the actual driving on the expressways, and anxiety EEGs increased at the same speed, when subjects drove on the roads with a design speed of 90km/h and 100km/h. It means that there were small differences in road alignment and standard. However, the running speed to make drivers feel anxious was increased at both roads with a design speed of 110km/h and 120km/h. It implies that drivers can drive at a higher speed, as road alignment and standard improve.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.39 no.4
• /
• pp.98-106
• /
• 2011

Establishing conservation programs to protect and maintain populations of endangered species are not only a global trend, but also a pursuit endorsed by the Korean Environmental Conservation Act. This study evaluates the feasibility of alternative habitat patches for the endangered butterfly Parnassius bremeri. A portion of habitat of P. bremeri is expected to be fragmented and damaged due to the scheduled construction of the Sangju-Yongduk Highway. A trans fer of the habitat patches of P. bremeri is also scheduled. In order to select an alternative habitat patch, the Mark-Release-Recapture (MRR) method was used to simulate a patch transfer model. The connectedness between habitat are as and the survival of local populations were evaluated for each candidate habitat. It was found that metapopulations with patch distances of <250m showed a 50% connectedness and survival rate in local populations. P. bremeri were expected to migrate at an average distance of 300m. In addition, P. bremeri formed a metapopulation that exhibited intimate patch dynamics that promoted persistence among these patches. Possible candidate habitats including those recommended by local governing bodies were evaluated along with habitats that may counter problems arising from the damage done to the original habitat and habitats that may have a compensatory value equal to that of the original habitat. Based on these criteria, Ansa-myeon township office was selected due to its high scores. This scoring was based on a consideration of a wide range of variables that mark a successful transfer of habitat. These include the amount of funding available, the governing bodies of the possible alternative habitat, and the Expected collaborative effort of local citizens. This decision was collaborated on by incorporating the expertise of various fields of study including biology, ecology, biogeography, ecological engineering, landscape architecture, and social sciences. Therefore, it is suggested that in order to evaluate an alternative habitat for organisms, many social issues as well as ecological issues must be considered.

• KIPS Transactions on Software and Data Engineering
• /
• v.7 no.9
• /
• pp.351-360
• /
• 2018

The LWR (Locally Weighted Regression) model, which is traditionally a lazy learning model, is designed to obtain the solution of the prediction according to the input variable, the query point, and it is a kind of the regression equation in the short interval obtained as a result of the learning that gives a higher weight value closer to the query point. We study on an incremental ensemble learning approach for LWR, a form of lazy learning and memory-based learning. The proposed incremental ensemble learning method of LWR is to sequentially generate and integrate LWR models over time using a genetic algorithm to obtain a solution of a specific query point. The weaknesses of existing LWR models are that multiple LWR models can be generated based on the indicator function and data sample selection, and the quality of the predictions can also vary depending on this model. However, no research has been conducted to solve the problem of selection or combination of multiple LWR models. In this study, after generating the initial LWR model according to the indicator function and the sample data set, we iterate evolution learning process to obtain the proper indicator function and assess the LWR models applied to the other sample data sets to overcome the data set bias. We adopt Eager learning method to generate and store LWR model gradually when data is generated for all sections. In order to obtain a prediction solution at a specific point in time, an LWR model is generated based on newly generated data within a predetermined interval and then combined with existing LWR models in a section using a genetic algorithm. The proposed method shows better results than the method of selecting multiple LWR models using the simple average method. The results of this study are compared with the predicted results using multiple regression analysis by applying the real data such as the amount of traffic per hour in a specific area and hourly sales of a resting place of the highway, etc.

• International Journal of Highway Engineering
• /
• v.7 no.4 s.26
• /
• pp.151-162
• /
• 2005

Variable Message Sign (VMS), which provides drivers with direct information about state of traffic congestion and for prevent an accident, is the most effective method among the methods of providing information in Advanced Transportation Management System. Currently establishment and the VMS which is operated foundation lets in Guidelines on the use of Variable message sign (a book of the VMS) of 1999 November the Ministry Construction & Transportation, these contents mean main viewpoint on physical part such as message special quality variable (font, character size and line space, word interval) and position mainly among standard about establishment in general. But, it is true that using without effect verification on the character of VMS display and that using mode of stationary-centered. In this paper, it executed significance test to effort verification on the character of VMS display for more practical and effective information transmission based on the driver viewpoint For the researches; develop 3D-Simulation, select characteristics of driver's visual cognition behavior (the conspicuity, the legibility and the comprehensibility), evaluation each issue (day or night, 80km/h or 100km/h). Especially, that used the Eye Marker Recorder to measure of reading-time (legibility) thus, confirmed objectivity and reduce an observational error. The results showed that the conspicuity is Flashing> Stationary>Scroll. The legibility is not deference that Flashing between stationary form. Also the comprehensibility result showed that Flashing> Stationary>Stroll form.