• Steel and Composite Structures
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• 제5권6호
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• pp.459-484
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• 2005

In recent years, the use of steel tube confined concrete (STCC) columns has been the interests of many structural engineers. The present study is an attempt to study the monotonic and cyclic behaviours of STCC columns. For the monotonic behaviours, a series of tests on STCC stub columns (twenty one), and beam-columns (twenty) were carried out. The main parameters varied in the tests are: (1) column section types, circular and square; (2) tube diameter (or width) to thickness ratio, from 40 to 162, and (3) load eccentricity ratio (e/r), from 0 to 0.5. For the cyclic behaviours, the test parameters included the sectional types and the axial load level (n). Twelve STCC column specimens, including 6 specimens with circular sections and 6 specimens with square sections were tested under constant axial load and cyclically increasing flexural loading. Comparisons are made with predicted column strengths and flexural stiffness using the existing codes. It was found that STCC columns exhibit very high levels of energy dissipation and ductility, particularly when subjected to high axial loads. Generally, the energy dissipation ability of the columns with circular sections was much higher than those of the specimens with square sections. Comparisons are made with predicted column strengths and flexural stiffness using the existing codes such as AIJ-1997, AISCLRFD- 1994, BS5400-1979 and EC4-1994.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.87-94
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• 1999

The structural behavior of welded steel box columns subjected to axial compression and combined load of axial and horizontal load is described. The nonlinear stress-strain relation of the material and residual stress resulted from welds were included in the analysis. Inelastic buckling analysis of hollow rectangular sections of various width-thickness and slenderness ratios was carried out using the semi-analytical and spline finite strip method to investigate the local and global bucking stress and mode interaction. The buckling stress was compared with test results and design curves. Post-buckling behavior was traced by the finite element program(ADINA) and compared with experimental results. The comparison showed that the ultimate stress can be used for the design purpose.

• 한국강구조학회 논문집
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• 제26권5호
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• pp.453-461
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• 2014

본 연구에서는 건축구조용 고성능강 HSA800의 건축구조부재로의 적용을 위한 연구로써, 용접 제작된 각형강관 및 H형강에 대해 단주편심압축 실험을 바탕으로 해석모델을 이용한 검증이 이루어졌다. 특히, 고성능강 조립단주의 유한요소해석을 이용한 변수연구와 P-M 상관관계로부터 현행 기준의 적용여부를 평가하고자 하였으며, 폭두께비와 축력비를 주요변수로 두었다. 변수모델의 P-M상관도 분석결과, 압축력에 대한 비세장단면은 모두 현행기준의 요구에서 크게 상회하는 결과를 얻었고 축력비가 낮을수록 휨강도비에 충분한 여유를 갖는 것을 확인하였다. 압축력에 대한 세장판 단면을 갖는 각형강관의 경우, 현행기준의 요구에 못 미치는 결과를 보였다.

• 한국강구조학회 논문집
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• 제11권3호통권40호
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• pp.251-258
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• 1999

본 연구는 각형강관을 이용한 프랫트러스의 N형 접합부의 거동을 연구하는 것으로 접합부를 보강하지 않고 접합형상만을 변화시켜 접합부의 구조적 특성을 향상시키는데 그 목적이 있다. 주요변수는 주관에 대한 지관의 폭비, 압축지관과 인장지관 사이의 갭 크기비와 편심비 등이며, 지관회전 여부에 따라 분류, 정방형(NSE계열)과 지관 $45^{\circ}$ 회전형(NPE계열)에 대한 각종 변수별 내력과 변형성상을 실험을 통해 규명하였으며, 지관을 $45^{\circ}$ 회전할 경우 최대내력 및 변형성상이 재선됨을 밝혀내었다. 또한, 실험결과로부터 각 계열별 평균극한강도식을 도출하였으며, NSE계열의 경우 현행 유럽의 규준식을 국내 실정에 맞도록 수정, 제안하였고, NPE계열은 편심비의 영향을 고려할 수 있는 실험식을 제안하였다.

• Steel and Composite Structures
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• 제30권2호
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• pp.185-199
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• 2019

Modular construction is an emerging technology to accommodate the increasing restrictions in terms of construction period, energy efficiency and environmental impacts, since each structural module is prefabricated offsite beforehand and assembled onsite using industrialized techniques. However, some innate structural drawbacks of this innovative method are also distinct, such as connection tying inaccessibility, column instability and system robustness. This study aims to explore the theoretical and numerical stability analysis of a tenon-connected square hollow section (SHS) steel column to address the tying and stability issue in modular construction. Due to the excellent performance of composite structures in fire resistance and buckling prevention, concrete-filled steel tube (CFST) columns are also taken into account in the analysis to evaluate the feasibility of adopting composite sections in modular buildings. Characteristic equations with three variables, i.e., the length ratio, the bending stiffness ratio and the rotational stiffness ratio, are generated from the fourth-order governing differential equations. The rotational stiffness ratio is recognized as the most significant factor, with interval analysis conducted for its mechanical significance and domain. Numerical analysis using ABAQUS is conducted for validation of characteristic equations. Recommendations and instructions in predicting the buckling performance of both SHS and CFST columns are then proposed.

• 한국구조물진단유지관리공학회 논문집
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• 제19권1호
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• pp.45-52
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• 2015

섬유복합체 (Fiber Reinforced Polymer, FRP)는 비강도가 높고, 비부식성 재료라는 특징을 가지고 있어서 건설 분야에서 철근을 대체할 수 있는 보강근 재료로 인식되고 있다. 몇몇 유리섬유 복합체 (Glass FRP, GFRP) 보강근이 상용화되어 있지만 GFRP는 철근에 비해 가격이 비싸고 상대적으로 낮은 탄성계수와 취성 파괴 특성 때문에 다소 경쟁력이 떨어진다. GFRP 보강근의 재료가격을 낮출 수 없다면 사용된 재료의 성능을 최대로 하여 보강근의 성능을 높이는 것이 상대적인 가격을 낮추는 방법이 될 수 있다. 일반적으로 FRP 보강근의 직경이 커질수록 인장강도는 감소하는 것으로 알려져 있다. 이의 원인 중 하나는 보강근이 인장을 받을 때 외력이 중앙에 위치한 섬유에 충분히 전달되지 못하여 외측에 위한 섬유들만이 인장에 저항하기 때문이다. 따라서 본연의 역할을 수행하지 못하는 섬유는 제거함으로써 보강근의 단가를 낮추면서 보강근이 소정의 성능을 발휘하도록 한다면 가격대비 성능이 최적화된 FRP 보강근을 제작할 수 있다. 본 연구에서는 직경 19 mm의 GFRP 보강근에 대해 단면 내에 중공이 존재하는 경우 중공비율에 따른 인장특성의 변화를 실험적으로 관찰하였다. 중공이 없는 GFRP 보강근 세 개, 네 가지 중공비율에 대해 각각 여섯 개의 GFRP 보강근 시편을 준비하여 인장실험을 실시하였으며 결과 분석을 통하여 인장특성 변화를 도출하였으며 이를 바탕으로 최적의 중공비율을 제안하였다.

• Structural Engineering and Mechanics
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• 제45권4호
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• pp.439-454
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• 2013

Hollow cylindrical tubes with a prismatic sandwich lining designed to replace the solid cross-sections are studied in this paper. The sections are divided by a number of revolving periodic unit cells and three topologies of unit cells (Square, Triangle and Kagome) are proposed. Some types of multiple-topology designed materials are also studied. The feasibility and accuracy of a homogenization method for obtaining the equivalent parameters are investigated. As the curved elements of a unit cell are represented by straight elements in the method and the ratios of the lengths of the curved elements to the lengths of the straight elements vary with the changing number of unit cells, some errors may be introduced. The frequencies of the first five modes and responses of the complete and equivalent models under an internal static pressure and an internal step pressure are compared for investigating the scope of applications of the method. The lower bounds and upper bounds of the number of Square, Triangular and Kagome cells in the sections are obtained. It is shown that treating the multiple-topology designed materials as a separate-layer structure is more accurate than treating the structure as a whole.

• Structural Engineering and Mechanics
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• 제43권3호
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• pp.287-309
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• 2012

Precast segmental bridge columns (PSBC) are alternatives for monolithic cast-in-situ concrete columns in bridge substructures, with fast construction speed and structural durability. The analytical tool for common use is demonstrated applicable for seismic performance prediction of PSBCs through experiment conducted earlier. Then the analytical program was used for parameter optimization of PSBC configurations under reversal cyclic loading. Shear strength by pushover analysis was compared with theoretical prediction. Moreover, seismic response of PSBC with energy dissipation (ED) bars was compared with its no ED bar counterpart under three history ground acceleration records. The investigation shows that appropriate ED bar and post-tensioned tendon arrangement is important for higher lateral bearing capacity and good ductility performance of PSBCs.

• Structural Engineering and Mechanics
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• 제45권6호
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• pp.723-740
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• 2013

This paper presents a parametric study of reinforced concrete bridge tall piers with hollow, rectangular sections. Such piers are typically used in railway construction of prestressed concrete viaducts. Twenty one different piers have been studied with seven column heights of 40, 50, 60, 70, 80, 90 and 100 m and three types of 10-span continuous viaducts, whose main span lengths are 40, 50 and 60 m. The piers studied are intermediate columns placed in the middle of the viaducts. The total number of optimization design variables varies from 139 for piers with column height of 40 m to 307 for piers with column height of 100 m. Further, the results presented are of much value for the preliminary design of the piers of prestressed concrete viaducts of high speed railway lines.

• KCI Concrete Journal
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• 제12권2호
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• pp.73-84
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• 2000

A new form of construction utilizing structural steel as the boundary elements in ductile flexural concrete walls is proposed to solve the bar congestion problems in such a heavily reinforced region, while maintaining the ductility and energy absorption capacity comparable to their traditional form. Two wall specimens containing rectangular hollow structural sections (HSS) and channels at their ends respectively, and one companion standard reinforced concrete wall specimen with concentrated end reinforcement were constructed and tested under reversed cyclic loading to evaluate the construction process as well as the structural performance. Initially, all three specimens were chosen and detailed with some caution to have approximately the same flexural capacity without change of the original shape and dimension of a rectangular cross section correction. Analysis and comparison of test results indicated that the reversed cyclic responses of three walls showed similar hysteretic properties, but in those with steel boundaries, local buckling of the corresponding steel webs and flanges following significant yielding was a dominant factor to determine the hysteretic response. The monotonic and cyclic responses predicted based on a sectional approach was also presented and found to be in good agreement with measured results. Design recommendations considering local instability of the structural steel elements and the interaction between steel chords and a concrete web member in such a composite wall are presented.