• Journal of Environmental Impact Assessment
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• v.20 no.3
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• pp.325-335
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• 2011

Estuary is a transitional zone between river and ocean environment that receives the maritime and riverine influence simultaneously. Estuaries are the most productive habitats because their incoming water provides large quantities of nutrients. The Seomjin River estuary, located in the middle south of Korea, has no barrage and shows natural characteristic of estuary. However, due to dredging and reclamation the environment of the estuary has been changed significantly in the river mouth. In addition, increased freshwater intake in midstream of the Seomjin River results in salinity intrusion. In this paper salinity variation in downstream estuary of the Seomjin River has been simulated and tested using EFDC model. The results of simulation were compared with measured data collected at three points, Culture & Art Center, Sumjin Iron Bridge, and Mokdori, located at 9Km, 14Km, and 15.5Km respectively from downstream estuary. Based on the simulated results, the contribution of the flushing discharge has been evaluated in preventing the salinity intrusion by increasing the discharge flowrates released from the Juam dam.

• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.603-610
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• 2003

A damage identification technique using static displacement data is developed to asses s the structural integrity of bridge structures.As such, the relationship between static displacement and stiffness is derived, and the optimization technique utilized.Comparisons with numerical and experimental tests are performed to investigate the practical applicability of the proposed method.Various damage scenarios are considered by varying damage-width as well as damage-degree. The influence of noise in identifying the damage is also numerically investigated.Finally, the applicability and limitation of the proposed method are discussed.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.730-731
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• 2015

This study aims at giving the framework to estimate the environmental load at planning and schematic phase. With increasing awareness of environmental issues, the effort to reduce the environmental impacts caused by human activity has been increasingly enlarged. So far most of researches estimating CO₂ emissions have analyzed energy consumption based on BOQ (Bills of Quantity) acquired after detailed design. There is also lack of reliability in the estimated environmental impact using the basic unit of a facility at the planning stage, because it uses a limited specific section of historical data. Thus, this study is targeted at developing framework to assess reliable environmental loads based on information available at project early phases by making case-bases from historical design information on PSC Beam Bridge. Historical database is built on the basis of the LCA (Life Cycle Assessment) and in order to set input information for estimating model, the literature about information in an early project phase are reviewed. Using the information available in the planning and schematic design stage, the Framework is presented to estimate the environmental load in an early stage in the project. Developing an environmental load estimation model in accordance with the Framework presented in this study, it is expected that the environmental load in the initial project phase can be estimated more quickly and accurately.

• Earthquakes and Structures
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• v.26 no.2
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• pp.87-96
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• 2024

This paper proposes a logistic multinomial regression approach to model the spatial cross-correlation of damage probabilities among different damage states in an expanded transportation network. Utilizing Bayesian theory and the multinomial logistic model, we analyze the damage states and probabilities of bridges while incorporating damage correlation. This correlation is considered both between bridges in a network and within each bridge's damage states. The correlation model of damage probabilities is applied to the seismic assessment of a portion of Tehran's transportation network, encompassing 26 bridges. Additionally, we introduce extra daily traffic time (EDTT) as an operational parameter of the transportation network and employ the shortest path algorithm to determine the path between two nodes. Our results demonstrate that incorporating the correlation of damage probabilities reduces the travel time of the selected network. The average decrease in travel time for the correlated case compared to the uncorrelated case, using two selected EDTT models, is 53% and 71%, respectively.

• Journal of the Korea Concrete Institute
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• v.16 no.3 s.81
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• pp.357-367
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• 2004

In this paper, the effect of cumulative damage for reinforced concrete bridge piers subjected to both single and multiple earthquakes is investigated. For this purpose, selected are three set of accelerograms one of which represents the real successive input ground motions, recorded at the same station with three months time interval. The analytical predictions indicate that piers are in general subjected to a large number of inelastic cycles and increased ductility demand due to multiple earthquakes, and hence more damage in terms of stiffness degradation is expected to occur. In addition, displacement ductility demand demonstrates that inelastic seismic response of piers can significantly be affected by the applied input ground motion characteristics. Also evaluated is the effect of multiple earthquakes on the response with shear. Comparative studies between the cases with and without shear indicate that stiffness degradation and hence reduction in energy dissipation capacity of piers are pronounced due to the multiple earthquakes combined with shear. It is thus concluded that the effect of multiple earthquakes should be taken into account for the stability assessment of reinforced concrete bridge piers.

• Explosives and Blasting
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• v.11 no.2
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• pp.60-68
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• 1993

The noise and vibration generated by the subway rolling stocks operated along the Seoul Subway Line No.1, 2, 3, and 4 lead to a controversy of pollution problem especially in residential areas. However, there is no data or guide to define the damage or provide adequate protection against such pollutions. The field measurements were made to characterize the noise attenuation due to distance, noise level distribution around the subway track of the aboveground and underground parts of each Line. The assessment criteria and methods are considered in addition to the practical available noise control methods. The noise level measured at Line No. 1 and 3 are less than 60 dB(A) with no pollution problem. Only a part of the aboveground section of Line No.2 and 4 indicates severe noise pollution. The effective boundary of these areas exposed to 70dB (A) noise are within 50m from the track centerline of No.2 line and 25m of No.4 line. The residents file a strong complaints whenever the noise level exceeds the 80dB (A) , and an occasional complaints between 70 to 80 dB(A). The distribution of high level noise of 80 dB(A) occurs within 25m from the track centerline of the overbridge, 12.5m of the short steel bridge, and about loom of the long steel bridge such as Dangsan Bridge. The intermediate noise level of 70 to 80 dB(A) is recorded within 50m from the overbridge, U-type retaining structure, and short steel structure, and 280m from the long steel bridge. The results presented in this paper can be used to understand the characteristics of the noise pollution along the Seoul Subway now In operation, and used as a guide to improve the existing noise pollution problems.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.393-398
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• 2004

It is transformed map data of different coordinate system into unique system and We triedto make topographic map on non-accessible area. We transformed Russian map coordinates(Krassovsky, G-K projection) intoWGS-84, TM projection and assessed accuracy. The RMSE(in East and West bearings : ${\pm}$13.67m, in North and South bearings ： ${\pm}$14.67m) using only SCP(Survey Control Point) is more accurate than that(in East and West bearings ： ${\pm}$24.26m, in North and South bearings : ${\pm}$25.32m) using SCP, intersection of road, bridge. Exterior orientation parameters are estimated using rigorous modelling and GCPs are classified with SCP, intersection of road, bridge. Rigorous modelling is performed with each classified GCP. The modelling result usingonly SCP(in East and West bearings : ${\pm}$13.53m, in North and South bearings ： ${\pm}$14.22m) is more accurate than that using intersection of road(in East and West bearings ： ${\pm}$16.l1m, in North and South bearings： ${\pm}$23.85m), bridge(in East and West bearings : ${\pm}$17.21m, in North and South bearings : ${\pm}$21.82m). The results means that SCP is more accurate than intersection of road, bridge because of edit to generate map. therefore, SCP is suitable for object of GCP in paper map(1:50,000). Geographic information on non-accessible area and analysis is performed. The results of stereoscopic plotting is well matched old map data on road, railroad but, many objects are generally editted. It is possible to update on new objects(building, tributary ‥‥etc). Ability of description using SPOT-5(stereo) is more than features and items included in 1:50,000 topographic map. Therefore, it is possible to make large scale map than 1:50,000 topographic map using SPOT-5 imagery. But, there are many problems(accurate GCPs, obtain of high resolution stereoscopic satellite imagery in a period ‥‥ etc) to make topographic map on non-accessible area. It is actually difficult to solve these problems. therefore, it is possible to update 1:50,000 topographic map in part of topographic map generation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.3
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• pp.151-162
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• 2024

As the incidence direction of ground motion (or seismic wave) changes, the seismic response of the structure will also change according to that direction. In order to analyze the effect of the seismic response of the example bridge according to the direction of incidence of ground motion, the acceleration response spectra (S_a-T1) corresponding to the 1-second period obtained for various angles of incidence were obtained. Using S_a-T1, 40 sets of orthogonal pairs of horizontal component seismic waves corresponding to 5 types of percentiles were generated. Seismic vulnerability analysis of the bridge piers was performed by obtaining the seismic response of an example bridge according to the direction of incidence of ground motion. By analyzing the seismic vulnerability analysis of seismic waves corresponding to five types of percentiles, it was found that the median value of the seismic vulnerability curve differs by about 1.2 to 2.6 times depending on the incident direction of the seismic wave. In other words, depending on the incidence direction of seismic waves, the degree of damage to the bridge structure can vary by about 1.2 to 2.6 times.

• Clinics in Shoulder and Elbow
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• v.18 no.4
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• pp.206-210
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• 2015

Background: Assessment of the clinical outcomes after rotator cuff repair is essential for their effectiveness on treatment. The Korean Shoulder and Elbow Society devised the Korean Shoulder Scoring System (KSS) for patients with rotator cuff disorder. The purpose of this study was to evaluate the availability of the KSS for assessment of clinical outcomes in patients after arthroscopic rotator cuff repair, and for comparison with other appraisal scoring systems. Methods: A total of 130 patients with partial-thickness or full-thickness rotator cuff tear who underwent arthroscopic repair using a single row or double row suture bridge technique were enrolled. The average follow-up period was 25.9 months. All patients were classified according to various factors. Comparison within corresponding categories was performed, and the correlation between the KSS and other shoulder assessment methods including University of California Los Angeles (UCLA), Constant and American Shoulder and Elbow Surgeons (ASES) score was analyzed. Results: Total score of the KSS response had increased from 59.6 preoperatively to 88.96 at last follow-up. All KSS domains, including function, pain, satisfaction, range of motion, and muscle power had improved up to 24 months postoperatively. Statistical significance was observed mainly in preoperative measurements with number and size of torn tendons, and greater than or equal to grade 3 of fatty infiltration. The KSS was best correlated with the UCLA scoring system in both preoperative (r=0.785) and postoperative (r=0.951) measurements. Conclusions: The KSS was highly reliable and valid as a discriminative instrument, and it showed strong correlation with ASES and UCLA scoring systems.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.4
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• pp.107-117
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• 2014

This study tests homogeneity and performs multiple comparison analysis among treatment levels of each factor group through t-test by materials and analysis of variance by structural type and service period. For that descriptive statistical analysis is performed for static and dynamic response characteristics and their ratios of calculated versus measured values based on a good many safety assessment reports for bridges. Homogeneity and post hoc test based on descriptive statistical analysis provide the measures for homogeneity identification among comparison groups in addition to the statistical reference values such as central tendency, variation and shape. This study is expected to be valuable for structural integrity assessment and design by comparing the measured and calculated values with the reference values for the homogeneous group identified, which can help the engineers review the adequacy of the values and put the group database to practical use.