• 한국강구조학회 논문집
• /
• 제19권1호
• /
• pp.117-127
• /
• 2007

이 연구에서는 기둥에 축방향 하중을 받고 있는 강재 상자단면 접합부의 강도를 이론적 해석적 검토를 통하여 평가하였다. 2층 교각구조에서는 기둥에 작용하고 있는 축방향 하중의 영향으로 T형 접합부 강도가 저하되게 된다. 이러한 현상을 검토하기 위해 비선형 유한요소해석을 수행하였고, 실험결과와의 비교를 통하여 유한요소 해석프로그램 및 해석방법의 타당성을 검증하였다. 강재라멘교각 접합부의 설계변수 중 패널존의 폭-두께비 파라메타와 플랜지와 복부판의 단면적비 및 기둥에 작용하는 축방향 하중의 영향을 비선형 유한요소해석을 통하여 검토하였다. 또한 이 연구에서는 축방향 하중의 증가에 따른 T형 상자단면 접합부의 응력분포를 이용하여 이론적인 강도평가식을 유도하였다. 또한 1층 교각 구조의 상자단면 접합부 강도특성과 비교하였다. 결국, 패널존의 폭-두께비 파라메타와 단면적비의 영향을 고려하여 T형 접합부의 강도평가식을 제안하였다.

• Steel and Composite Structures
• /
• 제21권2호
• /
• pp.357-371
• /
• 2016

Column base connections are critical components in steel structures because they transfer axial forces, shear forces and moments to the foundation. Exposed column bases are quite commonly used in low- to medium-rise buildings. To investigate shear transfer in exposed column base plates, four large scale specimens were subjected to a combination of axial load (compression or tension) and lateral shear deformations. The main parameters examined experimentally include the number of anchor rod, arrangement of anchor rod, type of lateral loading, and axial force ratio. It is observed that the shear resisting mechanism of exposed column base changed as the axial force changed. When the axial force is in compression, the resisting mechanism is rotation type, and the shear force will be resisted by friction force between base plate and mortar layer. The specimens could sustain inelastic deformation with minimal strength deterioration up to column rotation angle of 3%. The moment resistance and energy dissipation will be increased as the number of anchor rods increased. Moreover, moment resistance could be further increased if the anchor rods were arranged in details. When the axial force is in tension, the resisting mechanism is slip type, and the shear force will be resisted by the anchor rods. And the shear resistance was reduced significantly when the axial force was changed from compression to tension. The test results indicated that the current design approach could estimate the moment resistance within reasonable acceptance, but overestimate the shear resistance of exposed column base.

• 자동차안전학회지
• /
• 제8권1호
• /
• pp.26-30
• /
• 2016

The steel road wheel on ventilation holes was cracked in the vehicle durability test. But the component durability test by uni-axial, CFT(Cornering Fatigue Test) and RFT(Radial Fatigue Test) had been satisfied. That is, the uni-axial component test could not forecast the crack of vehicle. Therefore this study developed the bi-axial test mode to reflect a vehicle condition(to reflect both vertical and lateral force simultaneously) based on real load data which was measured in Europe and China and developed CAE simulation too. It reproduced the cracks same as vehicle's and verified by bi-axial test machine in the LBF(Fraunhofer Institute for Structural Durability and System Reliability) durability research center in Germany. Finally this the durability CAE simulation by using HMC(Hyundai Motor Company)'s the bi-axial test mode predicts feasibly the steel wheel's durability performance before vehicle durability test.

• Steel and Composite Structures
• /
• 제18권1호
• /
• pp.71-90
• /
• 2015

Axial compression tests have been carried out on 18 rectangular concrete-filled cold-formed steel tubular (CFST) columns with the aim of investigating the axial behaviour of rectangular CFST columns under different loading methods (steel loaded-first and full-section loaded methods). The influence of different loading methods on the ultimate strength of the specimens was compared and the development of Poisson's Ratio as it responds to an increasing load was reported and analysed. Then, the relationship between the constraining factor and the strength index, and the relationship between the constraining factor and ductility index of the specimens, were both discussed. Furthermore, the test results of the full-section loaded specimens were compared with five international code predicted values, and an equation was derived to predict the axial carrying capacity for rectangular CFST columns with a steel loaded-first loading method.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2000년도 가을 학술발표회 논문집
• /
• pp.159-166
• /
• 2000

A new method of estimating axial nail force is proposed. An instrumented soil nail wall is selected to investigate the effectiveness of the new proposed method. The new method includes effect of creep and age of cement grout surrounding the steel bar, The new method also considers cracks in the grout generated during and after the end of the wall construction. It is found from this study that a reduced grout stiffness due to creep with age and crack of the grout must be considered for estimating correct axial nail forces. The reduced grout stiffness is considered also providing significant part of axial nail load compared to that of steel bar.

• 한국철도학회논문집
• /
• 제8권3호
• /
• pp.276-285
• /
• 2005

This study discussed the effect on rail's axial force due to thermal and seismic loads according to supporting conditions of railway bridges; the considered supporting conditions are 1)simply supported, 2)roller at both ends, and 3)roller with horizontal spring at both ends. Closed form solutions are used to calculate the axial farces on rails. The roller at both ends of a bridge span decreases the compressive axial force on rail due to thermal load compared with the simply supported condition. However, the lateral springs at roller are not helpful to decrease the rail's compressive axial force.

• 소성∙가공
• /
• 제9권1호
• /
• pp.35-42
• /
• 2000

In this paper, we developed the hydroforming simulator which can apply an axial compressive force and high internal pressure to bulge a tube. Experimental dtudies have been performed to investigate the effect of each parameters such as internal pressure and axial compression stroke required for the forming of circular components. Under the improper forming conditions there were two forming failures. One was the axial buckling due to excessive axial compressive load and the other was the circumferential necking fracture due to relatively high internal pressure. A safe forming zone without any failures exists between these two extreme zones. Also the condition of forming failure such as fracture is examined throughout the theoretical analysis. This paper covers a brief overview of the mechanism of hydroforming process as well as the design of die and tools.

• Structural Engineering and Mechanics
• /
• 제40권2호
• /
• pp.215-231
• /
• 2011

The axial compressive strength of unidirectional FRP is generally quite lower than its axial tensile strength. This fact decreases the advantages of FRP as main load bearing member in engineering structure. In order to restrain the lateral expansion and splitting of GFRP, and accordingly heighten its axial compressive bearing capacity, a project that to confine GFRP pole with surrounding CFRP sheet is suggested in the present study. The Experiment on the CFRP sheet confined GFRP poles showed that a combined structure of high bearing capacity was attained. Basing on the experiment research a theoretical iterative calculation approach is suggested to predict the ultimate axial compressive stress of the combined structure, and the predicted results agree well with the experimental results. Then the influences of geometrical parameters on the ultimate axial compressive stress of the combined structure are also analyzed basing on this approach.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2000년도 봄 학술발표회 논문집
• /
• pp.173-182
• /
• 2000

To find axial and lateral responses of impact-driven H piles in embankment(SM), the H piles are instrumented with electric strain gages, dynamic load test is performed during driving, and then the damage of strain gages is checked simultaneously. Axially and laterally static load tests are performed on the same piles after one to nine days as well. Then load-settlement behavior is measured. Furthermore, to find the set-up effect in H pile, No. 4, 16, 26, and R6 piles are restriked about 1, 2, and 14 days after driving. As results, ram height and pile capacity obtained from impact driving control method become 80cm and 210.3∼242.3ton, respectively. At 15 days after driving, allowable bearing capacity by CAPWAP analysis, which 2.5 of the factor of safety is applied for ultimate bearing capacity, increases 10.8%. Ultimate bearing capacity obtained from axially static load test is 306∼338ton. This capacity is 68.5∼75.7% at yield force of pile material and is 4∼4.5 times of design load. Allowable bearing capacity using 2 of the factor of safety is 153∼169ton. Initial stiffness response of the pile is 27.5ton/mm. As the lateral load increases, the horizontal load-settlement behaves linearly to which the lateral load reaches up to 17ton. This reason is filled with sand in the cavity formed between flange and web during pile driving. As the result of reading with electric strain gages, flange material of pile is yielded at 19ton in horizontal load. Thus allowable load of this pile material is 9.5ton when the factor of safety is 2.0. Allowable lateral displacement of this pile corresponding to this load is 23∼36mm in embankment.

• 한국강구조학회 논문집
• /
• 제20권5호
• /
• pp.655-663
• /
• 2008

본 연구에서는 콘크리트충전 원형강관(원형 CFT)기둥의 내화성능을 평가하기 위하여 수치해석을 수행하였다. 강관은 SPSR 400 강재를 사용하였으며 강관 내에는 27.5MPa와 37.8MPa 강도의 콘크리트를 사용하였다. 콘크리트 강도, 작용 축력, 단면 직경을 변수로 설정하였다. 수치해석의 정확성을 검증하기 위하여, 기존의 각국 내화성능설계식들에 의한 계산 결과값과 비교 평가 하였다. 또한, 기존의 실대 원형 CFT기둥의 내화성능 평가 실험 결과와 함께 비교 분석하여 수치해석의 타당성을 검증하였다. 원형 CFT기둥의 내화실험 및 수치해석적 연구를 통해 도출된 내화저항시간과 축력비, 단면직경, 콘크리트 강도의 영향을 각형 CFT기둥의 내화성능과 비교 분석하여 각 영향인자들의 영향을 평가하였다. 본 연구의 수치해석적 연구는 실험결과와 비슷한 거동 및 내화성능을 보였다. 따라서 본 연구에서의 수치해석에 의한 CFT기둥의 내화 성능 예측은 타당하다고 판단된다.