• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.84-85
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• 2014

Green frame is column-beam structure composed of precast concrete members. Based on Revision of Structural Concrete Design Code, the bottom rebar of beam shall be extend at least 150mm into the support member. However, if the bottom rebar extend to satisfy Revision of Structural Concrete Design Code, the installation fo beam is impossible due to interference between the columns and beams. Thus, the aim of this study is estimation of production length of precast concrete beam by using splice length of bottom rebar. In this study to solve this problem, lap splice were used on the join. This study was calculated length of the reinforcement by the diameter. According to the length of the rebar, the production length of beam concrete was calculated. The results of this study will satisfy the Revision of Structural Concrete Design Code about column-beam connection when green frame will be applied.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.171-172
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• 2011

Green column and green beam, key structural members of green frame, have the characteristics of post-lintel structure, thanks to the steel frame in the connection, enabling prompt and precise installation. The connection of green frame can be divided into 4 types, depending on its shape, and each type is associated with different characteristics and construction methods. Notably, as the connection between green columns have differing types and sequences of work, subject to the connection method in use, a connection method optimized for relevant site conditions need to be selected. Therefore, this study analyzed pros and cons of 4 different types of green frame connection methods. The results set forth herein will provide basic data for subsequent studies to comparatively analyze the performance and constructibility of different green frame connection methods.

• Steel and Composite Structures
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• 제7권3호
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• pp.201-217
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• 2007

Two combinatorial optimization algorithms, tabu search and simulated annealing, are presented for the minimum-weight design of geometrically non-linear steel plane frames. The design algorithms obtain minimum weight frames by selecting suitable sections from a standard set of steel sections such as American Institute of Steel Construction (AISC) wide-flange (W) shapes. Stress constraints of AISC Load and Resistance Factor Design (LRFD) specification, maximum and interstorey drift constraints and size constraints for columns were imposed on frames. The stress constraints of AISC Allowable Stress Design (ASD) were also mounted in the two algorithms. The comparisons between AISC-LRFD and AISC-ASD specifications were also made while tabu search and simulated annealing were used separately. The algorithms were applied to the optimum design of three frame structures. The designs obtained using tabu search were compared to those where simulated annealing was considered. The comparisons showed that the tabu search algorithm yielded better designs with AISC-LRFD code specification.

• Steel and Composite Structures
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• 제27권3호
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• pp.285-295
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• 2018

In this paper, the bearing capacity of a non-eccentric and eccentric tubular, concrete-filled, steel bridge pier was studied through the finite element method. Firstly, to verify the validity of the numerical analysis, the finite element analysis of four steel tube columns with concrete in-fill was carried out under eccentric loading and horizontal cyclic loading. The analytical results were compared with experimental data. Secondly, the effects of the eccentricity of the vertical loading on the seismic performance of these eccentrically loaded steel tubular bridge piers were considered. According to the simulated results, with increasing eccentricity ratio, the bearing capacity on the eccentric side of a steel tubular bridge pier (with concrete in-fill) is greatly reduced, while the capacity on the opposite side is improved. Moreover, an empirical formula was proposed to describe the bearing capacity of such bridge piers under non-eccentric and eccentric load. This will provide theoretical evidence for the seismic design of the eccentrically loaded steel tubular bridge piers with concrete in-fill.

• Steel and Composite Structures
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• 제22권5호
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• pp.1073-1084
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• 2016

Rectangular concrete-filled steel tubular columns with unequal wall thickness were investigated in the paper. The physical centroid, the centroidal principal axes of inertia, and the section core were given. The generalized bending formula and the generalized eccentric compression formula were deduced, and the equation of the neutral axis was also provided. The two rectangular concrete-filled steel tubular stub specimens subjected to the compression load on the physical centroid and the geometric centroid respectively were tested to verify the theoretical formulas.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.337-338
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• 2012

As a rahmen structure, the connection among columns of Green frame is divided into three types such as sleeve, coupler (column pre and post installation), and bolt. The bolt type consists of six types according to steel frame shape and each type has different constructability, safety, structural performance, cost, and quality. Therefore, the analysis of comparison among the types is necessary. The objective of this study is to analyze the characteristics according to the shape of six bolt types to select the appropriate connection of Green frame. The results of this study can be used as a basic study for indentifying the characteristics of steel frame on site applying bolt type connection of Green frame. In addition, this study can be applicable to compare and analyze the performance and constructability of six bolt types in detail.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2011년도 정기 학술대회
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• pp.706-709
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• 2011

최근 환경오염 문제에 대한 관심이 고조되며 건설분야를 비롯한 각 산업분야에서는 $CO_2$저감 대책에 대한 연구가 활발히 진행되어 왔다. 건설분야에서의 기존 연구는 대부분 시공 후 사용 및 유지관리 단계에 집중되어 있으며, 설계단계에서 구조재료 및 비구조 재료의 적절한 사용에 관련한 연구는 초기단계이다. 그러므로 본 연구에서는 초고층건물 구조설계에서 사용되는 매입형 합성기둥 부재의 구조비용과 $CO_2$발생량을 동시에 최소화할 수 있는 다목적 최적설계기법을 제안하였다. 알고리즘의 검증을 위해 35층 건물의 기둥 설계에 적용하였으며, 적용결과 초기설계안보다 경제적이며 친환경적인 최적 설계안을 제시할 수 있음을 확인하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제5권1호
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• pp.161-168
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• 2001

The use of composite members to improve the compressive strength of steel structure is a common practice these days and its efficiency has already been proved by several researches and experiments. The result of concrete filled circular tubular(CFCT) stub column tests is introduced in this paper. The main parameter of this test is the ratio of diameter to thickness of circular hollow section. From the test results, the effect of concrete filled in steel tube on the ultimate strength, the deformation capacity and initial stiffness are discussed. The purpose of this paper is to investigate the effect of various parameters and evaluate the compressive strength of confined concrete. It would contribute to a better understanding of CFT structure, further laboratory experimentations are needed for better accurate estimation on its effect.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.21-22
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• 2015

The CFT(Concrete Filled Tube) system has been developed to behave well in a structural performance such as stiffness, stress, ductility, fire resistance that is derived from its mechanical advantages of composite structure. There were number of studies about unprotected CFT columns for improving their fire resistance through reinforcing bars or plates being placed inside the steel tube. It was also known that reinforcing plates of flat type need stiffeners in a certain distance to avoid their buckling failure so it cost as much as their using consequentially. This paper is planned to test the work of beam elements attached inner side of CFT depending on its shape. More discussions on beam's design could be followed after some fire tests accordingly conducted within this project.

• Structural Engineering and Mechanics
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• 제14권2호
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• pp.119-133
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• 2002

A beam-column fiber element for the large displacement, nonlinear inelastic analysis of Concrete-Filled Steel Tubes (CFT) is implemented. The method of description is Total Lagrangian formulation. An 8 degree of freedom (DOF) element with three nodes, which has 3 DOF per end node and 2 DOF on the middle node, has been chosen. The quadratic Lagrangian shape functions for axial deformation and the quartic Hermitian shape function for the transverse deformation are used. It is assumed that the perfect bond is maintained between steel shell and concrete core. The constitutive models employed for concrete and steel are based on the results of a recent study and include the confinement and biaxial effects. The model is implemented to analyze several CFT columns under constant and non-proportional fluctuating concentric axial load and cyclic lateral load. Good agreement has been found between experimental results and theoretical analysis.