• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.235-242
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• 2003

The solids and the fluids in porous media have a relative velocity to each other. Due to physically and chemically different material properties and their relative velocity, the behavior of saturated porous media is extremely complicated. Thus, in order to describe and clarify the deformation behavior of saturated porous media, constitutive models for deformation of porous media coupling several effects such as flow of the fluids or thermodynanical change need to be developed in frame of Arbitrary Lagrangian Eulerian (ALE) description. The aim of ALE formulations is to maximize the advantages of Lagrangian and Eulerian elements, and to minimize the disadvantages. Therefore, this method is appropriate for the analysis of porous media that are considered for the behavior of the solids and the fluids. In this work, governing equations of porous media based on ALE description are obtained from governing equations in frame of updated Lagrangian description. Then, weak forms of these equations are derived using arbitrary weighting functions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.339-340
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• 2012

Green frame is combined by structural steel and reinforcements of Green column and beam and unified by cast-in-place concrete. However, when upper reinforcements penetrate structural steel hole, the execution is difficult due to interference of joint and a rib of deformed reinforcements. Therefore, the objective of this study is to propose the reinforcement tools to improve productivity of precast structure connection construction. The reinforcement tools proposed in this study can be helpful to improve constructability, safety, duration, and cost comparing with conventional reinforcement method since unskilled workers can deal with reinforcements easily.

• Structural Engineering and Mechanics
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• v.46 no.5
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• pp.645-672
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• 2013

The differential settlements and rotations among footings cannot be avoided when the frame-footing-soil system is subjected to seismic/dynamic loading. Also, there may be a situation where column(s) of a building are located near adjoining property line causes eccentric loading on foundation system. The strap beams may be provided to control the rotation of the footings within permissible limits caused due to such eccentric loading. In the present work, the seismic interaction analysis of a three-bay three-storey, space frame-footing-strap beam-soil system is carried out to investigate the interaction behavior using finite element software (ANSYS). The RCC structure and their foundation are assumed to behave in linear manner while the supporting soil mass is treated as nonlinear elastic material. The seismic interaction analyses of space frame-isolated footing-soil and space frame-strap footing-soil systems are carried out to evaluate the forces in the columns. The results indicate that the bending moments of very high magnitude are induced at column bases resting on eccentric footing of frame-isolated footing-soil interaction system. However, use of strap beams controls these moments quite effectively. The soil-structure interaction effect causes significant redistribution of column forces compared to non-interaction analysis. The axial forces in the columns are distributed more uniformly when the interaction effects are considered in the analysis.

• Journal of the Korean housing association
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• v.26 no.2
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• pp.103-110
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• 2015

Precast Concrete (PC) construction method can be the one that is suitable for long-life housing due to its merit in respect of maintenance and durability based on crack-free from mass production with indirect construction cost-saving-effect due to shortening construction period comparing to the conventional construction method, but it has the problem that causes the raise of direction construction costs. So, this study analyzed its economic feasibility of PC method whose maintenance and durability are excellent for underground parking lot of apartment house for accomplishing cost-saving long-life housing by applying the various structural system. In evaluation of unit module structural system, two-way PC system requires 10 to 28% more costs for frame work than RC rigid frames, and, one-way PC system 98~112%. Although it varies depending on the method, the costs are similar to RC rigid frame structure, provided a proper method is adopted. Also, Model 11, which was most economical in the evaluation, was applied to an real parking lot and about 2 to 6% of construction costs was reduced than RC rigid frames. This seems to be because, although PC system has a higher production cost, introduction of P.S (prestress) reduces member depth and, therefore, height, as well as the number of members per unit module.

• Computational Structural Engineering
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• v.4 no.1
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• pp.83-94
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• 1991

This paper presents an efficient and accurate method for nonlinear analysis of frame structures by idealized structural unit method. The main idea behind the present method is to minimize the computational effort by reducing the number of unknowns. An explicit form of the tangential elastic stiffness matrix of the element is derived by the principle of virtual work. The ultimate limit state of the element is judged on the basis of the formation of a plastic hinge mechanism. The elasto-plasto-plastic stiffness matrix of the element is derived by plastic node method and the post-ultimate stiffness equation is formulated under a simple analytic consideration. A comparison between the present solution and the existing experimental and other numerical result for unit column member and simple frame structure is made. If is clear from the result of this study that the present method is very useful because the computing time required is very small while giving the accurate solution.

• Journal of the Korea Institute of Building Construction
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• v.11 no.5
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• pp.482-500
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• 2011

In apartment housing construction, window frame installation work, which is conducted after the structural framework, is very important, because its completion time directly affects the starting time of successive interior finishing works, as well as the overall construction period. Construction delays in interior finishing works might occur due to problems inherent to the conventional window frame installation method, such as the poor verticality of window frames, and the water leakage around them. The primary objective of this study is to analyze the problems of a 'Gangform integrated PVC window frame pre-installation method' based on its pilot test results. Next, this study proposes an improved conceptual model that enables the end users to enhance the field applicability of this method in terms of productivity, time, and cost. The field applicability of the proposed 'Gangform integrated PVC window frame pre-installation method' was also verified through a survey.

• Journal of KIBIM
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• v.8 no.2
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• pp.41-50
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• 2018

The current study focused on the utilization of building information modeling (BIM) data in steel-frame structures, which help to reduce project durations because they employ prefabricated structural members that are assembled on-site. In addition, a business process model was proposed using BIM data collected during the preconstruction, structural steel fabrication, and on-site construction phases of an actual steel-frame project. The ultimate expectation is that BIM data support at each phase, as well as the increased understanding among project participants, will result in an increase in project management productivity. The results from the current study are summarized as follows: To implement a BIM capable of application to steel-frame projects and data utilization, existing theories were studied to develop the construction project steps, both generally into the preconstruction (A1), steel fabrication (A2), and on-site construction phases, (A3) and specifically into 19 BIM-applicable phases. Based on the derived BIM-applicable phases, the model elements of the BIM object were identified, and the shortcomings of existing steel-frame projects were ameliorated, resulting in an improved data flow model. Moreover, for the proposed BIM data flow to progress efficiently, the BIM specialist needs to be well-acquainted with the phase-specific three-dimensional (3D) model output, and the infrastructure to construct an error-free 3D model must be provided. Based on the actual construction example, the BIM data utilized steel-frame projects - via production reports, clash checks, two-dimensional (2D) drawings, four-dimensional (4D) simulations, and 3D scanning - to make cooperation and communication among participants easier.

• Computational Structural Engineering
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• v.9 no.4
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• pp.219-228
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• 1996

A method used for measuring the stiffness of hinging reinforced concrete frame structures is developed. The so called Stiffness Measure Method is used to evaluate the tangent stiffness of hinge regions while the structure is responding in nonlinear ranges. Eigenvector methods for nonlinear response have not been especially popular because of the need for regenerating eigenvectors as the time history proceeds. In the present work the eigenvectors sets and corresponding nonlinear state variables, i. e., the tangent stiffnesses of the hinge regions, are stored. There is an expectation that previously generated eigenvectors can be reused as the analysis proceeds. The stiffness measure is used to compare the current tangent stiffnesses of hinge regions with those of previously stored eigenvectors sets. Since eigenvector calculations are diminished the method is effective in reducing computational effort for reinforced concrete frame structures subjected to strong ground motions.

• Earthquakes and Structures
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• v.23 no.6
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• pp.549-580
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• 2022

This paper assesses the influences of modeling assumptions and uncertainties on the performance of the non-linear finite element (FE) model updating procedure and model clustering method. The results of a shaking table test on a four-story steel moment-resisting frame are employed for both calibrations and clustering of the FE models. In the first part, simple to detailed non-linear FE models of the test frame is calibrated to minimize the difference between the various data features of the models and the structure. To investigate the effect of the specified data feature, four of which include the acceleration, displacement, hysteretic energy, and instantaneous features of responses, have been considered. In the last part of the work, a model-based clustering approach to group models of a four-story frame with similar behavior is introduced to detect abnormal ones. The approach is a composition of property derivation, outlier removal based on k-Nearest neighbors, and a K-means clustering approach using specified data features. The clustering results showed correlations among similar models. Moreover, it also helped to detect the best strategy for modeling different structural components.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.3-7
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• 2009

Construction projects are being the skyscraper and the large size by limited site condition and developing construction technology. Therefore, Steel structure work is steadily increasing caused by easy to work and structural safety. However, steel-frame work has the large incidence of heavy accident potentially. Recently a research group has recently developed newly designed self-supported steel joint for enhancing safety of steel erection work. Before applying the steel joint in a construction site, economic evaluation should be performed. Thus, we proposed the method for measuring economic efficiency of the new steel joint and verified economic feasibility of the steel joint method through a case study. As a result, Steel erection method using by self-supported steel joint showed economic rather than the one using by H-beams.