• Special Issue of the Society of Naval Architects of Korea
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• 2017.10a
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• pp.73-79
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• 2017

IACS enacted Harmonized CSR(CSR-H) to meet the IMO GBS applied from 1 July 2016. CSR-H is clearly complement and integrate than present CSR-BC & CSR-OT. One of the biggest issue in new rule is structural analysis. In CSR-H, structural analysis must carried out entire each cargo area including the aft bulkhead of the aftermost cargo hold and the collision bulkhead. Accordingly, new load and boundary conditions are present, an additional structural reinforcement is required by the structural analysis result for each cargo hold. In this study, we applied CSR-H to existing 158K DWT CLASS CRUDE OIL TANKER in order to compare and analyze the hull changes. It is useful for the application of the CSR-H to the similar vessel and helpful in finding the optimized structural design.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.496-499
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• 2006

In this study, a practical method of shrinkage stress analysis on concrete slab in multi-story building is proposed, which considers both internal restraint and external restraint variation resulting from construction sequence. The shrinkage stress due to external restraint is obtained by multiplying relaxation coefficient to elastic shrinkage stress. The additional shrinkage stress due to internal restraint is obtained by residual strain of the elastic analysis. A verification example was analyzed and compared by the proposed method and commercial analysis program that is capable of time-dependent analysis of concrete. The results of 10-story example building show that the internal restraint of reinforcement increases the shrinkage stress considerably at the slabs under loose external restraint.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.157-162
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• 2012

A structural modification of baseframe is an effective method to avoid resonance in marine diesel generator (D/G) set which consists of diesel engine, generator and baseframe. However the reinforcement with thick plates or additional parts to increase the natural frequency can be less effective because of increased weight. Especially fine control of target mode based on the experience is difficult because the weight and interference of system have to be considered. In this paper, the design optimization of baseframe was performed to reduce the resonant vibration using a gradient descent method. The design parameters such as thickness, shape and location of baseframe parts are optimized to increase the torsional natural frequency of D/G set. From the actual test, the new designed baseframe reduced the vibration level in resonance by 55% without any increase of weight and interference. interference.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.609-614
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• 1997

Recently, many researchers have performed R&D about strengthening of R/C with steel plates, carbon fiber sheets. aramid fiber sheets and glass fiber sheets, and so on. However most of research were limited in study of flexural strengthening of R/C beams. This paper shows the results of an experimental study on shear reinforcement of deep beams using Glass Fiber Sheet in relation to shear-span ratio. strengthening orientation and anchorage. The results prove that shear failure is governed by reinforced orientation. adherence and anchorage. Additional anchorage of fibers does not only cause the improvement in the internal resistance, but also control the brittle shear failure of specimen after reaching the maximum load.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.408-415
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• 1997

Bond strength of reinforcing bar to high-performance concrete using Belite cement is explored using beam end test specimen. The key parameters for the bond test are slump of concrete, top bar effect, and strength of concrete in addition to concrete covers. Specimen failed in the typical brittle bond failure splitting the concrete cover as the wedging action. The test results show that for the group with portland cement I using superplasticizer additional slump does not decrease the bond strength of the top bar is less than bond strength of bottom bar, but the top bar factor satisfy the modification factor for top reinforcement. The result also show that bond strength is function of square root of concrete compressive strength and cover thickness. More detailed evaluation will be conducted from the test specimen with high strength concrete using the belite cement.

• KCID journal
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• v.17 no.2
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• pp.28-34
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• 2010

This study re-exams hydrologic stability on spillway outlet capacity of agricultural reservoirs using hydrologic data with current rainfall condition instead of project hydrologic data applied at design on Backgok reservoir located in Chungbuk province. It is concluded that Backgok reservoir is not hydrologically stable and therefore structural measures including the extension of spillway and non structural measures should be taken. Continuous basic plan for river maintenance including additional bank reinforcement to bottom river shall be carried out. Due to high peak flood with more than 290% compared to 200 year frequency probability flood which was design standard of the past in view of the results of calculating PMF according to revised design standard for reservoirs, there could a problem for securing rationality in case of applying PMF with design flood. Therefore, hydrological stability, construction, and maintenance cost shall be synthetically studied and reasonal application shall be made if the decision is made on applying PMF with design flood.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.236-241
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• 2011

An active trailing-edge flap blade named as Seoul National University Flap (SNUF) blade is designed for reducing helicopter vibratory loads and the relevant aeroacoustic noise. Unlike the conventional rotor control, which is restricted to 1/rev frequency, an active control device like the present trailing-edge flap is capable of actuating each individual blade at higher harmonic frequencies i.e., higher harmonic control (HHC) of rotor. The proposed blade is a small scale blade and rotates at higher RPM. The flap actuation components are located inside the blade and additional structures are included for reinforcement. Initially, the blade cross-section design is determined. The aerodynamic loads are predicted using a comprehensive rotorcraft analysis code. The structural integrity of the active blade is verified using a stress-strain recovery analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.1
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• pp.227-238
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• 2003

Due to deterioration of bridge, usually be using the external prestressing method among repair reinforcement method. But, there is much to be desired about a detailed account, almost it has analysed by cambers of girders, deflections of middle span and upper, bottom stresses of girders. Also, it is not examined closely that effect of internal prestress by external prestressing. The purpose of this study is confirmed the effect of internal tendons by external prestressing, estimation of additional external prestressing force and look for exact external prestressing force.

• Steel and Composite Structures
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• v.19 no.5
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• pp.1237-1258
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• 2015

This paper proposes a simple inelastic analysis approach to efficiently map out the complete nonlinear post-collapse (strain-softening) response and the maximum load capacity of axially loaded concrete encased steel composite columns (stub and slender). The scheme simultaneously incorporates the influences of difficult instabilizing phenomena such as concrete confinement, initial geometric imperfection, geometric nonlinearity, buckling of reinforcement bars and local buckling of structural steel, on the overall behavior of the composite columns. The proposed numerical method adopts fiber element discretization and an iterative M${\ddot{u}}$ller's algorithm with an additional adaptive technique that robustly yields solution convergence. The accuracy of the proposed analysis scheme is validated through comparisons with various available experimental benchmarks. Finally, a parametric study of various key parameters on the overall behaviors of the composite columns is conducted.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.37
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• pp.217-250
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• 2008

The International Ship and Port Facility Security (ISPS) Code which was developed as the main response of the shipping sector to the miserable event of 11 September 2001 came into effect on 1 July 2004. The ISPS Code designed to detect and eliminate security threats affecting ships and port facilities used in international trade will significantly impact not only on the management and operation of the shipping industry but also on maritime law despite the fact that it is the regulatory framework of public law. It is expected that implementing the ISPS Code will contribute to reinforcement of maritime security on the one hand. However, on the other hand, more intensified security inspection and control measures of port states will also cause delay and additional costs which cause uncertainty in allocating security risk and cost between the contracting parties. Therefore, it is desire to insert new security clause dealing with main security issues or adapt existing clauses to new shipping environments to minimize disputes.