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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Computational Structural Engineering Institute of Korea
Journal Basic Information
Journal DOI :
The Computational Structural Engineering Institute
Editor in Chief :
Volume & Issues
Volume 28, Issue 6 - Dec 2015
Volume 28, Issue 5 - Oct 2015
Volume 28, Issue 4 - Aug 2015
Volume 28, Issue 3 - Jun 2015
Volume 28, Issue 2 - Apr 2015
Volume 28, Issue 1 - Feb 2015
Selecting the target year
Probabilistic Assessment of Dynamic Properties of Offshore Wind Turbines Considering Soil-Pile Interaction
Yi, Jin-Hak ; Kim, Sun-Bin ; Han, Taek Hee ; Yoon, Gil-Lim ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 4, 2015, Pages 343~350
DOI : 10.7734/COSEIK.2015.28.4.343
Extensive discussion on the optimal types of offshore wind turbine(OWT) among monopile, tripod and jacket in the intermediate depth of water has been actively carried out in worldwide wind turbine industry. Selecting the optimal types of OWT among several substructural types, it is required to consider the economic and technical feasibility including dynamically stable design of a wind turbine system. In this study, the effects of loading levels and uncertainties of soil properties on the natural frequency of OWT have been quantitatively investigated. In conclusion, the natural frequency of monopile-type OWTs has a significant level of uncertainty, hence it is very important to minimize the level of uncertainties in soil properties when the monopile is selected as a foundation for an OWT.
Uncertainties Influencing the Collapse Capacity of Steel Moment-Resisting Frames
Shin, Dong-Hyeon ; Kim, Hyung-Joon ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 4, 2015, Pages 351~359
DOI : 10.7734/COSEIK.2015.28.4.351
In order to exactly evaluate the seismic collapse capacity of a structure, probabilistic approach is required by considering uncertainties related to its structural properties and ground motion. Regardless of the types of uncertainties, they influence on the seismic response of a structures and their effects are required to be estimated. An incremental dynamic analysis(IDA) is useful to investigate uncertainty-propagation due to ground motion. In this study, a 3-story steel moment-resisting frame is selected for a prototype frame and analyzed using the IDA. The uncertainty-propagation is assessed with categorized parameters representing epistemic uncertainties, such as the seismic weight, the inherent damping, the yield strength, and the elastic modulus. To do this, the influence of the uncertainty-propagation to the seismic collapse capacity of the prototype frame is probabilistically evaluated using the incremental dynamic analyses based on the Monte-Carlo simulation sampling with the Latin hypercube method. Of various parameters related to epistemic uncertainty-propagation, the inherent damping is investigated to be the most influential parameter on the seismic collapse capacity of the prototype frame.
The Development of Mechanical Damper Using the Friction Pendulum Principle
Lee, You-In ; Han, Woo-Jin ; Ji, Yong-Soo ; Baek, Jun-Ho ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 4, 2015, Pages 361~368
DOI : 10.7734/COSEIK.2015.28.4.361
Recently, the earthquake has been increasing a lot, damage of electric power facility has been serious as well. Nowadays, the importance of pipe support system such as Hanger, Brace, Snubber connecting the main structure have been emphasized. These devices can prevent pipe from damage so that reduce the vibration and shock acting on the pipe. For this reason, the FCD(Friction Concave Damper) was developed and has been expected to reduce the vibration on the pipe through the Friction Pendulum System. This paper was described the introduction of self-developed mechanical damper using the friction pendulum principle and the characteristic test was performed to verify the performance of the device. Additionally the test results have been compared with predicted F.A.P(FCD Analysis Program-self developed) results. As a result, reliability of design could be improved.
Prestressing Loss Management for PSC Girder Tendon Based on EM Sensing
Kim, Junkyeong ; Park, Jooyoung ; Zhang, Aoqi ; Lee, Hwanwoo ; Park, Seunghee ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 4, 2015, Pages 369~374
DOI : 10.7734/COSEIK.2015.28.4.369
In this paper, an EM sensing based prestressing force estimation method is proposed, in which it can estimate tensile force of PS tendon for PSC girder. The PSC girder has more improved performance than the general concrete girder by introducing the prestressing to the concrete. Thus the PSC girder bridge is widely constructed due to its high performance and low cost. However, the prestressing force has not been managed nevertheless it is major factor for the maintenance of the PSC girder bridge. The prestressing force was just measured during construction using jacking device and after that, it can not be managed. For this reason, this paper proposes a tensile force estimation method of PS tendon based on EM sensor. The permeability of ferroelectric material is changed according to the induced stress to the material, in which it can be measured using EM sensor. To measure the permeability of PS tendon, the EM sensor was fabricated and verified by performing the MTS test. The test was performed using 7-wire steel tendon under the 0, 40, 80, 120, 160, 200 KN of tensile force. The permeability of PS tendon was gradually decreased according to the increasement of tensile force. The regression method was used to find the relation between permeability and stress. As a result, the permeability has linear relation with the tensile force of PS tendon and the pre-stressing force can be estimated by the derived estimation equation.
Vibration Reduction Evaluation of Jacket Structure by applying Precast Concrete Block and Suction pile
Lee, Sung-Jin ; Kyung, Kab-Soo ; Ryu, Seong-Jin ; Jeong, Ji-Young ; Park, Jin-Eun ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 4, 2015, Pages 375~384
DOI : 10.7734/COSEIK.2015.28.4.375
Recently, construction sites of offshore wind power tend to move from shallow water to deep water. From this tendency, the research on the support structure of offshore wind power in deep water will be a key issue. In this study, precast concrete block and suction pile are applied to existing jacket structure. In order to reduce the vibration of this structure, the tuned liquid damper is also applied in the precast concrete block. The applicability of the suggested jacket structure is evaluated by finite element analysis. And the vibration tends to decrease about 5%, when the tuned liquid damper is applied.
City Information Model-based Information Management of Flood Damages
Park, Sang Il ; Kim, Min-Su ; Kim, Jong Myung ; Lee, Sang-Ho ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 4, 2015, Pages 385~392
DOI : 10.7734/COSEIK.2015.28.4.385
Open city information model can increase the understanding of the situation, enable the effective reuse of information due to access the semantic and relational conditions of objects, and support the reliable decision-making through linking with external references. The city information model focused on terrain and buildings was implemented based on the actual data. In addition, a process for flooding simulation was proposed using hydraulic analysis data and the city information model. The deaths and damages were estimated by flooding simulation. The availabilities were examined by detailed queries and responses based on model data of the city information model, hydraulic analysis data and the estimated damages.
Generation of Information Model for Modular Steel Bridge Superstructure Considering Module Assembly Condition
Seo, Kyung-Wan ; Park, Junwon ; Kwon, Tae Ho ; Lee, Sang-Ho ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 4, 2015, Pages 393~400
DOI : 10.7734/COSEIK.2015.28.4.393
This study proposes a method to create and combine a superstructure module by parametric modeling, in order to improve the production efficiency of information model for modular steel bridge superstructure that can be used in planning, design and construction phase. Compound classification was performed in order to derive elements to apply the parametric modeling, and according to assembly condition, the classified elements were grouped into 13 types. In addition, three assembly conditions were derived for production of stable superstructure through combination of superstructure module, which is a production unit for modular steel bridge factory. Parameter that reflects assembly condition in compound shape when producing superstructure module through parametric modeling was deducted. Superstructure module compounds were produced according to type and parameter using interface generation based on Building Information Model(BIM) software that was developed in this study. The superstructure module produced reflects information to combine into a superstructure. To verify this, information model based on Industry Foundation Classes(IFC) was built and confirmed the application in production of superstructure by identifying the reflected property information.
A Proposal of Model Updating Method for Steel Frame Using Global/Local Responses
Oh, Byung-Kwan ; Choi, Se-Woon ; Kim, Yousok ; Park, Hyo-Seon ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 4, 2015, Pages 401~408
DOI : 10.7734/COSEIK.2015.28.4.401
Conventional model updating methods for the structures have used global structural responses which are modal parameters obtained through vibration measurements. Although models updated by modal parameters estimate global structural responses accurately, they have difficulties to predict local responses for safety assesment of structural members. The safety of structural members in the structures has been evaluated through the stress estimation based on strain measurements. Thus, this study additionally uses measured strain responses of structural members to perform model updating besides modal parameters. In the proposed method, the objective functions are set to the differences of the global and local responses obtained from updated model and measurement and those functions are minimized by NSGA-II, one of the multi-objective optimization techniques. The strain responses predicted from updated model are used for safety assessment of the steel frame structures. The proposed method are verified by numerical and experimental studies through the impact hammer tests for a steel frame specimen.
An Alternative Perspective to Resolve Modelling Uncertainty in Reliability Analysis for D/t Limitation Models of CFST
Han, Taek Hee ; Kim, Jung Joong ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 4, 2015, Pages 409~415
DOI : 10.7734/COSEIK.2015.28.4.409
For the design of Concrete-Filled Steel Tube(CFST) columns, the outside diameter D to the steel tube thickness t ratio(D/t ratio) is limited to prevent the local buckling of steel tubes. Each design code proposes the respective model to compute the maximum D/t ratio using the yield strength of steel
and the elastic modulus of steel E. Considering the uncertainty in
and E, the reliability index
for the local buckling of a CFST section can be calculated by formulating the limit state function including the maximum D/t models. The resulted
depends on the maximum D/t model used for the reliability analysis. This variability in reliability analysis is due to ambiguity in choosing computational models and it is called as "modelling uncertainty." This uncertainty can be considered as "non-specificity" of an epistemic uncertainty and modelled by constructing possibility distribution functions. In this study, three different computation models for the maximum D/t ratio are used to conduct reliability analyses for the local buckling of a CFST section and the reliability index
will be computed respectively. The "non-specific
" will be modelled by possibility distribution function and a metric, degree of confirmation, is measured from the possibility distribution function. It is shown that the degree of confirmation increases when
decreases. Conclusively, a new set of reliability indices associated with a degree of confirmation is determined and it is allowed to decide reliability index for the local buckling of a CFST section with an acceptable confirmation level.
Magnetic Flux Leakage Method based Local Fault Detection for Inspection of Wire Rope
Kim, Ju-Won ; Park, Ju-Young ; Park, Seunghee ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 4, 2015, Pages 417~423
DOI : 10.7734/COSEIK.2015.28.4.417
In this study, Magnetic Flux Leakage(MFL)-based inspection system was applied to detect the local fault of wire rope. To verify the feasibility of the proposed damage detection technique, an 4-channel MFL sensor head prototype was designed and fabricated. A wire rope with several types of cross-sectional damages were fabricated and scanned by the MFL sensor head to measure the magnetic flux density of the wire rope specimen. To interpret the condition of the wire rope, magnetic flux signals were used to determine the locations of the flaws. To improve the resolution of signal, the instantaneous variation value of magnetic flux was utilized. Measured signals from the damaged specimen were compared with thresholds set for objective decision making. Finally, the results were compared with information on actual inflicted damages to confirm the accuracy and effectiveness of the proposed cable monitoring method.
Structural Design Optimization of Dynamic Crack Propagation Problems Using Peridynamics
Kim, Jae-Hyun ; Park, Soomin ; Cho, Seonho ;
Journal of the Computational Structural Engineering Institute of Korea, volume 28, issue 4, 2015, Pages 425~431
DOI : 10.7734/COSEIK.2015.28.4.425
Based on a bond-based peridynamics theory for dynamic crack propagation problems, this paper presents a design sensitivity analysis and optimization method. Peridynamics has a peculiar advantage over the existing continuum theory in the mathematical modelling of problems where discontinuities arise. For the design optimization of the crack propagation problems, a non-shape design sensitivity is derived using the adjoint variable method. The obtained adjoint sensitivity of displacement and strain energy turns out to be very accurate and efficient compared to the finite different sensitivity. The obtained design sensitivities are futher utilized to optimally control the position of bifurcation point in the design optimization of crack propagation in a plate under tension. A numerical experiment demonstrates that the optimal distribution of material density could delay the position of bifurcation.