• Steel and Composite Structures
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• 제1권1호
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• pp.51-74
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• 2001

A series of tests on concrete-filled SHS (Square Hollow Section) stub columns (twenty), columns (eight) and beam-columns (twenty one) were carried out. The main parameters varied in the tests are (1) Confinement factor (${\xi}$) from 1.08 to 5.64, (2) concrete compression strength from 10.7MPa to 36.6MPa, (3) tube width to thickness ratio from 20.5 to 36.5. (4) load eccentricity (e) from 15 mm to 80 mm and (5) column slenderness (${\lambda}$) from 45 to 75. A mechanics model is developed in this paper for concrete-filled SHS stub columns, columns and beam-columns. A unified theory is described where a confinement factor (${\xi}$) is introduced to describe the composite action between the steel tube and filled concrete. The predicted load versus axial strain relationship is in good agreement with stub column test results. Simplified models are derived for section capacities and modulus in different stages of the composite sections. The predicted beam-column strength is compared with that of 331 beam-column tests with a wide range of parameters. A good agreement is obtained. The predicted load versus midspan deflection relationship for beam-columns is in good agreement with test results. A simplified model is developed for calculating the member capacity of concrete-filled SHS columns. Comparisons are made with predicted columns strengths using the existing codes such as LRFD (AISC 1994), AIJ (1997), and EC4 (1996). Simplified interaction curves are derived for concrete-filled beam-columns.

• Advances in concrete construction
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• 제10권6호
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• pp.559-571
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• 2020

This study aimed to inspect the axial compression mechanical performance of basalt-fiber-reinforced recycled - concrete (BFRRC)-filled square steel tubular stub column. The replacement ratio of recycled coarse aggregate (RCA) and the basalt fiber (BF) dosage were used as variation parameters, and the axial compression performance tests of 15 BFRRC-filled square steel tubular stub column specimens were conducted. The failure mode and the load-displacement/strain curve of the specimen were measured. The working process of the BFRRC-filled square steel tubular stub column was divided into three stages, namely, elastic-elastoplasticity, sudden drawdown, and plasticity. The influence of the design parameters on the peak bearing capacity, energy dissipation performance, and other axial compression performance indexes was discussed. A mathematical model of segmental stiffness degradation was proposed on the basis of the degradation law of combined secant-stiffness under axial compression. The full-process curve equation of axial compressive stress-strain was proposed by introducing the influencing factors, including the RCA replacement ratio and the BF dosage, and the calculated curve agreed well with the test-measured curve.

• 한국강구조학회 논문집
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• 제12권4호통권47호
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• pp.339-350
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• 2000

본 연구의 목적은 개량 T-stub를 이용한 1층 1스팬 골조의 구조적 거동을 파악하고 중층규모의 건축물에 대하여 개량 T-stub의 적용가능성을 확인하기 위한 것이다. 연구방법으로 개량 T-stub 및 기존 T-stub를 이용한 반강접 골조의 반복가력실험을 하였으며 개량 T-stub의 플랜지 두께와 볼트중심거리를 변수로 하여 유한요소해석을 수행하여 그 결과를 실험결과와 비교하였다. 본 연구의 실험 및 해석결과로부터 개량 T-stub의 거동을 정성적으로 파악하고 반강접합부로서의 적용가능성을 확인하였다.

• Steel and Composite Structures
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• 제17권4호
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• pp.431-452
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• 2014

The present study focuses on the mechanical behaviour of concrete filled double skin steel tubular (CFDST) stub columns confined by fiber reinforced polymer (FRP). A series of axial compression tests have been conducted on two CFDST stub columns, eight CFDST stub columns confined by FRP and a concrete-filled steel tubular (CFST) stub column confined by FRP, respectively. The influences of hollow section ratio, FRP wall thickness and fibre longitudinal-circumferential proportion on the load-strain curve and the concrete stress-strain curve for stub columns with annular section were discussed. The test results displayed that the FRP jacket can obviously enhance the carrying capacity of stub columns. Based on the test results, a new model which includes the effects of confinement factor, hollow section ratio and lateral confining pressure of the outer steel tube was proposed to calculate the compressive strength of confined concrete. Using the present concrete strength model, the formula to predict the carrying capacity of CFDST stub columns confined by FRP was derived. The theoretically predicted results agree well with those obtained from the experiments and FE analysis. The present method is also adapted to calculate the carrying capacity of CFST stub columns confined by FRP.

• 한국강구조학회 논문집
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• 제18권6호
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• pp.805-813
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• 2006

이 논문은 T-stub를 이용한 접합을 반강접이 아닌 강접합의 범주에 두고 그 적용 가능성을 확인하기 위한 초기단계의 연구로서 초기강성에 관한 실험과 유한요소해석을 통하여 T-stub접합과 강접합의 초기강성을 비교하였다. 또한 해석결과를 통하여 T-stub를 이용한 기둥-보 접합부의 초기강성의 영향인자를 조사하였다.

• 한국강구조학회 논문집
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• 제9권4호통권33호
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• pp.479-487
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• 1997

강구조 건축물의 접합에서 강접합, 단순접합 이외에 반강접합의 이용이 고려될 수 있다. 반강접합의 장점으로서는 시공의 용이성과 부재의 효율적인 모멘트 분배가 가능하다는 점이다. 본 연구는 기존의 T-stub를 더 많은 회전능력이 생기도록 한 개량 T-stub를 접합요소로 선정하여 중층정도의 건축물에의 적용 가능성을 확인하기 위한 연구의 기초적 단계이다. 연구방법으로서는 개량 T-stub의 역학적 거동을 조사하기 위한 개량 T-stub요소의 인장 및 압축 실험과 개량 T-stub를 이용한 기둥-보 접합부의 단순재하실험이 실시되었다. 실험결과로부터 개량 T-stub의 정성적인 거동을 파악하였고, 개량 T-stub를 이용하면 반강접합으로서의 가능성도 확인하였다.

• 한국강구조학회 논문집
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• 제17권2호통권75호
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• pp.207-216
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• 2005

본 논문은 스테인리스 각형강관 및 원형강관에 대한 좌굴내력에 관한 연구로서 건축구조용 강재로서의 적용성 검토를 위해, 세장비를 주요 변수로 한 소재의 인장강도실험과 stub-column의 압축강도실험, 기둥의 중심압축실험을 실시하여 강재의 기계적 성질과 기둥의 강도 및 거동을 파악한다. 또한 이론해석과 각국 기준식(AIK-LSD, AISC-LRFD, AIJ-LSD, SIJ-ASD) 및 복수강도곡선의 적용을 통한 이론값과 실험값을 비교함으로서 건축구조용 강재로서 적용성 검토와 구조설계기준 확립을 위한 기초 자료를 구하는데 목적이 있다.

• 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.

• 한국강구조학회 논문집
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• 제10권2호통권35호
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• pp.153-160
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• 1998

각형 강관(${\boxe}-75{\times}75{\times}3.2,\;{\boxe}-100{\times}100{\times}4.2,\;{\boxe}-125{\times}125{\times}6.0$) 기둥의 단면 치수와 초기 변형을 측정하였다. 인장시험, 단주 압축강도 실험, 그리고 세장비 $46{\sim}84$ 사이의 기둥에 대한 압축강도 실험을 수행하였다. 유한요소법에 의한 기둥의 압축 강도를 산출하였다. 단면의 공칭 치수에 대한 측정값의 오차는 무시할 정도이며, 초기변형은 각 단면별로 세장비 100에 해당하는 기둥길이에 대해 초과 확률 2.5% 값이 각각 1/490, 1/1121, 1/1395로 나타났다. 인장시험 결과 강재의 항복강도는 최소 규정 강도보다 30% 이상 높다. 기둥 실험 결과 얻은 각형 강관 기둥의 압축강도는 단주 압축강도를 강재의 항복강도로 간주하고 비교하면 유한요소 해석 결과나 AISC, Eurocode의 강도 곡선과 거의 같거나 약간 높은 값이나, 강재의 최소 규정강도를 기준으로 비교하면 실험 결과가 훨씬 높은 강도를 보이는 것으로 나타났다.

• Steel and Composite Structures
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• 제42권1호
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• pp.91-106
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• 2022

Concrete-filled square stainless steel tubes (CFSSST), which possess relatively large flexural stiffness, high corrosion resistance and require simple joint configurations and low maintenance cost, have a great potential in constructional applications. Despite that the use of stainless steel may result in high initial cost compared to their conventional carbon steel counterparts, the whole-life cost of CFSSST is however considered to be lower, which offers a competitive choice in engineering practice. In this paper, a comprehensive experimental and numerical program on 24 CFSSST stub column specimens, including 3 austenitic and 3 duplex stainless steel square hollow section (SHS) stub columns and 9 austenitic and 9 duplex CFSSST stub columns, has been carried out. Finite element (FE) models were developed to be used in parametric analysis to investigate the influence of the tube thickness and concrete strength on the ultimate capacities more accurately. Comparisons of the experimental and numerical results with the predictions made by design guides ACI 318, ANSI/AISC 360, Eurocode 4 and GB 50936 have been performed. It was found that these design methods generally give conservative predictions to the ultimate capacities of CFSSST stub columns. Improved calculation methods, developed based on the Continuous Strength Method, have been proposed to provide more accurate estimations of the ultimate resistances of CFSSST stub columns. The suitability of these proposals has been validated by comparison with the test results, where a good agreement between the predictions and the test results have been achieved.