• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.1
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• pp.63-77
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• 2015

Tsunami take away life, wash houses away and bring devastation to social infrastructures such as breakwaters, bridges and ports. The coastal structure targeted object in this study can be damaged mainly by the wave pressure together with foundation ground failure due to scouring and liquefaction. The increase of excess pore water pressure composed of oscillatory and residual components may reduce effective stress and, consequently, the seabed may liquefy. If liquefaction occurs in the seabed, the structure may sink, overturn, and eventually increase the failure potential. In this study, the bore was generated using the water level difference, its propagation and interaction with a vertical revetment analyzed by applying 2D-NIT(Two-Dimensional Numerical Irregular wave Tank) model, and the dynamic wave pressure acting on the seabed and the surface boundary of the vertical revetment estimated by this model. Simulation results were used as input data in a finite element computer program(FLIP) for elasto-plastic seabed response. The time and spatial variations in excess pore water pressure ratio, effective stress path, seabed deformation, structure displacement and liquefaction potential in the seabed were estimated. From the results of the analysis, the stability of the vertical revetment was evaluated.

• Journal of Navigation and Port Research
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• v.30 no.6 s.112
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• pp.447-455
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• 2006

Together with the trend of enhancement in domestic industrial development and economic progress due to import and export, the demand for construction of the roads, bridges, especially port facilities, and several coastal protection and ocean structures is increasing rapidly. MOMAF of Korean Government is driving construction cf 9 new ports and renovation cf the existing fishery ports. Among these structures most of bridge base, wharves, dolphins, quays, and jetties are being newly built cf steel or concrete pile. As the base, supporting bulkheads, and piles are underwater after construction, it is difficult to figure out the status of structures and not enough to get maintenance and strengthen the structures. Every year, moreover, these works suck the government budget due to higher incomplete maintenance expense for protection from corrosions cf structures and increased underwater construction period. For the purpose cf cutting down the expense cf government budget, it is necessary to extend the life cycle of the existing structures. Therefore, we developed a new method for maintenance of submerged structures near the waterline by allowing dry work environment with the floating caisson. The method shows easy to move around the working area and handle. It also showed not only a significant reduction of maintenance expenses and time for anti-corrosion work but also better protection This will be a milestone to reduce the maintenance and construction expenses for the shore and water structures.

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.19-30
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• 2005

A coupled three-dimensional pile group analysis method was developed by considering complex behavior of sub-structures (pile-soil-cap) which included soil nonlinearity and the behavior of super-structure (pier). As an intermediate analysis method between FBPier 3.0 and Group 0.0, it took advantages of each method. Among the components of a pile group, individual piles were modeled with stiffness matrices of pile heads and soils with nonlinear load-transfer curves (t-z, q-z and p-y curves). A pile cap was modeled with modified four-node flat shell elements and a pier with three-dimensional beam element, so that a unified analysis could be possible. A nonlinear analysis method was proposed in this study with a mixed incremental and iteration techniques. The proposed method for a pile group subjected to axial and lateral loads was compared with othe. analytical methods (i.e., Group 6.0 and FBPier 3.0). It was found that the proposed method could predict the complex behavior of a pile group well, even though piles were modelled simply in this study by using pile head stiffness matrices which were different from the method introduced in FBPier 3.0.

• Explosives and Blasting
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• v.22 no.3
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• pp.57-64
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• 2004

There are two major types of underwater blasting at Korea, bridges and harbor construction work. Pier blasting for lay the foundation bridges construction is used dry excavation working (drilling and charging) after pump out water and then fire pump in water that is same as bench blasting. In contrast, underwater blasting for harbor construction and increase of harbor load depth is used to barge with digging equipment that is in oder to drilling on the surface and blasting work(charge, hook-up) under water. Thus, there are need to special concern such as charge method and hook-up method different from tunnel blasting work and bench blasting work. If do not use special concern breaks out dead pressure and mis fire because of there are so many difficult condition such as water pressure, obstruct field of vision. In this study underwater blasting at Busan Harbor Construction have consider with special concern that is plastic pipe charge method used to MegaMITE I and specialized buoy hook- up method make far initial system detonate on the surface used to TLD. The results is designed blast pattern charge per delay effect an inspection of verify between predict velocity and measure velocity. minimized break out mis fire consideration charge method, hook up method. According to result best underwater blasting design is 105mm drilling dia, MeGAMITE II, HiNLL Plus(non electric detonator).

• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.543-555
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• 1997

Generally, in a steel-concrete composite gilder, the shear connector which was constructed between concrete deck and steel girder should have enough stiffness to behave as one body, because the conformity between plate and concrete deck is influences by the stiffness and spacing of the shear connectors. If the stiffness of shear connectors are insufficient, slip would happen at the contact surface. Partial interaction is the case that takes account of slips. In this paper, an easy method is presented to evaluate the stiffness or spacing of the shear connector according to the degree of imperfection without difficult calculations for a composite gilder with partial interaction. Also, the horizontal shearing force applied to the shear connector and the longitudinal axial force, which is occurs at contact surface between concrete deck and steel girder, have been presented in a simple influence line that is various to the parameters of sectional properties, degree of imperfection and applied load points. Furthermore, through the case study, it determined the relationships between the degree of imperfection and the follows 1) spring constants 2) axial force and horizontal shearing force 3) stress and neutral axis by using the partial differential equation based on Newmark's Partial Interaction Theory.

• Spatial Information Research
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• v.22 no.5
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• pp.27-41
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• 2014

Recently, BIM(Building Information Modeling) has been applied to the infrastructure such as road and bridge, and information about the outside environment of buildings is needed for maintaining and managing the large urban facilities. In addition, the convergence between spatial information and Big-data has a large potentiality, in respect that considerable profits and developments in other application problems such as various simulations and urban plans, national land security, may be brought about on the basis of the interoperability of information between BIM and GIS. Therefore, this study attempted to suggest the development direction of a model integrating building for spatial information analysis and city on the subject by comparing and analyzing difference between information system and shape expression of IFC, CityGML and LandXML to efficiently link information between IFC as a standard model of BIM and CityGML as a standard model in the GIS sector and to prepare a basic fusion strategy and a method of utilization between BIM and GIS. The result of the study are as follow. Firstly, contents and structure of IFC, CityGML and LandXML are compared and analyzed. Secondly, the development direction of iBUM(Integrated Building and Urban Model) suggested, which is based on convergence technology for analysis of space information. Finally, a strategy and method of the BIM and GIS are proposed in the iBUM environment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.163-170
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• 2006

Together with the trend of enhancement in domestic industrial development and economic progress due to import and export, the demand for construction of the roads, bridges, especially port facilities, and several coastal protection and ocean structures is increasing rapidly. MOMAF of Korean Government is driving construction of 9 new ports and renovation of the existing fishery ports. Among these structures most of bridge base, wharves, dolphins, quays, and jetties are being newly built of steel or concrete pile. As the base, supporting bulkheads, and piles are underwater after construction, it is difficult to figure out the status of structures and not enough to get maintenance and strengthen the structures. Every year, moreover, these works suck the government budget due to higher incomplete maintenance expense for protection from corrosions of structures and increased underwater construction period. For the purpose of cutting down the expense of government budget, it is necessary to extend the life cycle of the existing structures. Therefore, we developed a new method for maintenance of submerged structures near the waterline by allowing dry work environment with the floating caisson. The method shows easy to move around the working area and handle. It also showed not only a significant reduction maintenance expenses and time for anti-corrosion work but also better protection. This will be a milestone to reduce the maintenance and construction expenses for the shore and water structures.

• Journal of the Korean Geotechnical Society
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• v.34 no.11
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• pp.81-92
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• 2018

For a marine bridge foundation construction, a large-circular-steel-pipe has been proposed for supporting vertical load and preventing water infiltration. However, a ship collision can adversely affect the structural stability. This paper presents a fundamental study on dynamic responses of the large-circular-steel-pipe by an impact load. In laboratory experiments, small-scaled steel pipe is installed in a soil tank. The soil height and water level are set to 23 cm and 25~70 cm, respectively. The upper part of the steel pipe is impacted using a hammer to simulate the ship collision. The dynamic responses are measured using accelerometers and strain gauges. Experimental results show that the strain decreases as the measured location is lowered. The higher frequency components appear in the impact load condition compared to the microtremor condition. However, the higher frequency components measured at the strain gauge located below the water level do not appear. For the accelerometer signal, the maximum frequency under the impact load is higher than that of the microtremor. The maximum frequency decreases as water level increases but it is larger than the maximum frequency of the microtremor. This study shows that strain gauge and accelerometer can be useful for evaluating the dynamic responses of large-circular-steel-pipes.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.75-89
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• 2006

This paper presents a practical and realistic Life-Cycle Cost (LCC) optimum design methodology of steel bridges considering time effect of bridge reliability under environmental stressors such as corrosion and heavy truck traffics. The LCC functions considered in the LCC optimization consist of initial cost, expected life-cycle maintenance cost and expected life-cycle rehabilitation costs including repair/replacement costs, loss of contents or fatality and injury losses, road user costs, and indirect socio-economic losses. For the assessment of the life-cycle rehabilitation costs, the annual probability of failure which depends upon the prior and updated load and resistance histories should be accounted for. For the purpose, Nowak live load model and a modified corrosion propagation model considering corrosion initiation, corrosion rate, and repainting effect are adopted in this study. The proposed methodology is applied to the LCC optimum design problem of an actual steel box girder bridge with 3 continuous spans (40 m+50 m+40 m=130 m), and various sensitivity analyses of types of steel, local corrosion environments, average daily traffic volume, and discount rates are performed to investigate the effects of various design parameters and conditions on the LCC-effectiveness. From the numerical investigation, it has been observed that local corrosion environments and the number of truck traffics significantly influence the LCC-effective optimum design of steel bridges, and thus realized that these conditions should be considered as crucial parameters for the optimum LCC-effective design.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.64-73
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• 2010

This research collected some multi-image information of Nakdong River Estuary Eulsukdo area in last 30 years, which are used as the basis information in running the qualitative analysis of the topography relief's deformation. First, to obtain the data, this research carried out a field survey and GCP measurement, then classified and collected the image information by analog and digital image. The acquired images which have passed a high-precise scan process and geometric correction is manufactured by Ortho Mosaic image, then divided them into 9 sections time period classification before we run a qualitative analysis. In late of 1980's there are many changes of environmental topography deformation of the Eulsukdo area which caused by large scale building constructions, appeared to be known through this research. And then in late of 1990's, we organized the wild cultivated lands, started the wetland restoration of the artificial ecology, in 2000's we are able to know the existence of topograph relief change which caused by big scale of bridge construction. Hereafter, in this quick process of the environmental and topographical change of this area caused by the 4 major rivers restoration project, the analysis results of this experiment are expected to be something applicable as important basic data.