• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.422-425
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• 1988

The structure consisting of an E-plane dielectric slab partially filling a rectangular waveguide is examined with attention on those higher order mode propagation characteristics that are relevant to the design of nonreciprocal remanence ferrite phase shifters. The mechanisms for the elimination of $LSE_{11}$, $LSM_{11}$, $LSE_{12}$ modes are introduced. Experimental verification of elimination of higher order mode is shown in the form of insertion loss measurements.

• Structural Engineering and Mechanics
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• v.21 no.3
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• pp.295-313
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• 2005

This paper evaluates the effective width of composite steel beams with precast hollowcore slabs numerically using the finite element method. A parametric study, carried out on 27 beams with different steel cross sections, hollowcore unit depths and spans, is presented. The effective width of the slab is predicted for both the elastic and plastic ranges. 8-node three-dimensional solid elements are used to model the composite beam components. The material non-linearity of all the components is taken into consideration. The non-linear load-slip characteristics of the headed shear stud connectors are included in the analysis. The moment-deflection behaviour of the composite beams, the ultimate moment capacity and the modes of failure are also presented. Finally, the ultimate moment capacity of the beams evaluated using the present FE analysis was compared with the results calculated using the rigid - plastic method.

• International Journal of High-Rise Buildings
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• v.7 no.1
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• pp.33-46
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• 2018

The Case Study prepared by PCPA and Lift Group will identify a growing development problem in urban areas; high value project sites that are restrictive in size or "tight" are underutilized and underdeveloped. In an effort to remedy this problem, our team will evaluate a design program through the lens of both conventional construction and Core Cantilever Construction. It is also important to differentiate between Core Cantilever construction and the plagued "Lift Slab" construction method as they may be confused, due to the top down construction sequence. This article will demonstrate that constraints inherent to conventional construction techniques prohibit economically viable development of these project sites, while Core Cantilever construction methods increase the projects value by reducing construction timelines and increasing the useable floor area.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1181-1186
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• 2000

The crack of concrete induced by the heat of hydration is a serious problem, particularly in concrete structures such as biers, thick walls, box type walls, mat-slab of nuclear reactor buildings, dams or foundations of high rise buildings, etc.. As a result of the temperature rise and restriction condition of foundation, the thermal stress which may induce the cracks can occur. Therefore the various techniques of the thermal stress control in massive concrete have been widely used. One of them is prediction of the thermal stress, besides low-heat cement which mitigates the temperature rise, design change which considers steel bar reinforcement, operation control and so on. In this study, firstly it introduce the thermal cracks control technique by employing low-heat cement concrete, thermal stress analysis considering season. Secondly it shows the application of the cracks control technique like block placement.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.989-994
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• 2000

Nine tests to failure are performed on full-scale eight composite beams with unreinforced web opening having ribbed slabs with formed deck which are perpendicular to the steel section and one steel beam. The effects of slab width, reinforcing of stud, moving of rib, moment-shear ratio are studied. At the low M/V ratio, Vierendeel action around the high moment end of the opening is occurred and the large deflection across the opening and transverse cracking are occurred with increasing of applied load. As the M/V ratio increases, the relative deflection across the opening decreases. And at failure, full tensile strain are occurred at bottom T section of steel beam, and concrete crushes at the High Moment End of the opening. With narrow slabs, diagonal tension failure at the high moment end of the opening is occurred. And with wide slabs, rib punch-through failure is occurred near the high moment end of the opening. The implications for design are discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 1992.04a
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• pp.107-113
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• 1992

The heat of hydration of cement the causes the internal temperature rise at early age, particulary in massive concrete structures such as a mat-slab of nuclear reactor building or a dam or a large footing. As the result of the temperature rise and restraint of foundation, the thermal stress enough to induce concrete cracks can occur. Therefore, the prediction of the thermal stress is very important in the design and construction stages in order to control the cracks developed in massive concrete structures. And, more creep and shrinkage take place at elevated temperatures in young concrete, Thus the effect of creep and shrinkage must be considered for checking the safety and servicebility(crack, durability and leakage).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.11
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• pp.51-57
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• 2014

This paper presents an algorithmic type computing technique of process coefficient in predicting model of temperature for reheating furnace and also suggests a design method of neural network model to find an adequate value of process coefficient for arbitrary operating conditions including test conditons. The proposed neural network use furnace temperature, line speed and slab information as input variables, and process coefficient is output variable. Reasonable process coefficients can be obtained by an algorithmic procedure proposed in this paper using process data gathered at test conditons. Also, neural network model output equal process coefficient under same input conditions. This means that adquate process coefficients can be found by only computing neural network model without additive test even if operating conditions vary.

• Steel and Composite Structures
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• v.20 no.6
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• pp.1237-1257
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• 2016

The paper concerns analysis of effects of shrinkage of slab concrete in a steel-concrete composite deck of a through truss bridge span. Attention is paid to the shrinkage alongside the span, i.e., transverse to steel-concrete composite cross-beams. So far this aspect has not been given much attention in spite of the fact that it affects not only steel-concrete decks of bridges but also steel-concrete floors of steel frame building structures. For the problem analysis a two-dimensional model is created. An analytical method is presented in detail. A set of linear equations is built to compute axial forces in members of truss girder flange and transverse shear forces in steel-concrete composite beams. Finally a case study is shown: test loading of twin railway truss bridge spans is described, verified FEM model of the spans is presented and computational results of FEM and the analytical method are compared. Conclusions concerning applicability of the presented analytical method to practical design are drawn. The presented analytical method provides satisfactory accuracy of results in comparison with the verified FEM model.

• Structural Engineering and Mechanics
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• v.26 no.3
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• pp.277-295
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• 2007

3-D wall panels are used in construction of exterior and interior bearing and non-load bearing walls and floors of building of all types of construction. Fast construction, thermal insulation, reduced labor expense and weight saving are the most well pronounced advantage of such precast system. When the structural performance is concerned, the main disadvantage of 3D panel, when used as floor slab, is their brittleness in flexure. The current study focuses on upgrading ductility and load carrying capacity of 3D slabs in two different ways; using additional tension reinforcement, and inserting a longitudinal concentrated beam. The research is carried on both experimentally and numerically. The structural performance in terms of load carrying capacity and flexural ductility are discussed in details. The obtained results could give better understanding and design consideration of such prefabricated system.

• Journal of Korean Association for Spatial Structures
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• v.18 no.1
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• pp.85-92
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• 2018

Construction techniques and materials are developing and structures are designed to be irregular shaped, and therefore more detailed structural analysis is required. The purpose of this study is to analyze the cause of accidents related to falsework systems during construction and discuss prevention methods in order to prevent accidents relate to prefabricated shoring system during construction. In this paper structural analysis was conducted to study the influence of slab irregularity on system supports and analysis to investigate the participation of the bracing in the system support.