• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.391-399
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• 2018

In this paper, experimental study performed on steel-pipe connections for structural members of a greenhouse is presented. By those experiments performed, bending moment, deformation and stress distribution of specimens were investigated under four point bending test. The bending performance according to connection method using pin and the stretching is also investigated. The results of bending performance of the no connection specimen were compared to those of other connection specimens. The pin and stretching connection specimens showed lower banding performance than the no connection specimen. The stretching connection method was relatively higher bending performance than the pin connection specimens. According to the results, we proposed the connection method with good bending performance that can be applied to steel-pipe connection in greenhouse.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.41-42
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• 2009

The purpose of this paper is to inspect a structural performance for the composite wall pile through static bending test. In result, all specimen came to failure in 1.8 times cracking load and the drift of the neutral axis on a load increasing occurred.

• Journal of the Korea Concrete Institute
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• v.13 no.5
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• pp.466-475
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• 2001

The potential shear strength of reinforced concrete beams decreases after flexural yielding due to the decrease of the effective compressive strength of concrete in plastic hinge zone. A truss model considering shear deterioration in the plastic hinge zone was proposed in order to evaluate the ductile capacity of reinforced concrete beams failing in shear after flexural yielding This model can determine the potential shear strength of the beam by using a truss model. The potential shear strength gradually decreases as the increase of the axial strain of member. When the calculated potential shear strength decreases up to the flexural yielding strength, the corresponding rotation angle is defined as the ductile capacity of the beam. The predicted ductile capacity of reinforced concrete beams is shown to be in a good agreement with experimental results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7244-7249
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• 2015

In this study, in order to asses the structural performance of trapezoidal PSC girder using a socket joint system and it is possible to calculate the optimized cross-section of the web element tests were carried out for each specimens. we conducted a socket joint performance test, web bending and shear performance tests and all tests were performed at 4 point loading method. The initial crack load of socket joint specimen was significantly lower than the reference specimen but post peak behavior was no significant differences. And the length of the loop joint of the reinforcing bars had no significant effect on the maximum load. As a web shear tests, to obtain a maximum load of the specimen has a prestressing rod reinforced at tension side. As a web flexural tests, to obtain higher diagonal cracking load in specimen of reinforced using prestressing rod than reference specimen.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3251-3259
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• 2014

This paper presents experimental and analytical research results to predict nonlinear flexural behavior of corroded reinforced concrete beams. For this purpose, a series of test and an analytical simulation using the Maaddawy's model were carried. Test specimens of total 12 RC beams were placed in accelerated corrosion status using salt water spray test chamber for 5 months and 10 months, after they were preloaded up to 30% and 60% of the maximum load corresponding to nominal flexural strength. The test results showed that flexural strength and ductility decreased to 5.4% and 43% at the most respectively due to breakdown of bond at the steel-concrete interface. Comparative study between the analytical predictions and the experimental results showed that the Maaddawy's model can be applied to predict a real corroded RC flexural members.

• Journal of Korean Society of Steel Construction
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• v.12 no.5 s.48
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• pp.595-604
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• 2000

Web openings of large beams provide space for wiring, piping, and duct work to provide for proper drainage, pipes and duct must be slightly sloped with the attendant result that all web openings can not be centered on the centroidal axes of the beams. Test specimens are made for opening-depth to beam-depth ratio of 0.5 and for eccentricities of the opening center line of 10% from middepth of the beam because of the proximity of the opening edge to the flange. In this paper, available test results and theories relating to the strength of composite beams having eccentric rectangular openings are surveyed and experiments were carried out to examine the structural behaviors. In all the tests in this paper good agreement is demonstrated with maximum loads measured in tests, and observed failure modes Furthermore, compared with analytical values and experimental values of interaction diagram between moment and shear capacity were safed as it is scattered with outer part of the analytical values.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.465-468
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• 2008

SHCCs (Strain Hardening Cement Composites) show the high energy tolerance capacity due to the interfacial bonding of the fibers to the cement matrix. For effective material design and application of SHCCs, it is needed to investigate the compression, four-point bending, direct tensile response of SHCCs with different types of fibers and water-cement ratio. For these purposes, three kinds of fibers were used: PP(polypropylene, 2.0%), PVA(Polyvinyl alcohol, 2.0%), PE (Polyethylene, 1.0%). Also, effects of water-cement ratio(0.45, 0.60) on the SHCCs were evaluated in this paper. As the result of test, SHCCs with PVA and PE fiber were showed better overall behavior than specimens with PP fibers on bending and direct tensile test. Also, for the same type of fiber, SHCCs with water-cement ratio of 0.45 exhibited higher ultimate strength than specimen with water-cement ratio of 0.60 on compression strength, and showed the multiple cracking on bending and direct tensile test. Therefore, to improve of workability and dispersibility of SHCCs on water-cement ratio of 0.60, continual studies were needed.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.157-157
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• 2011

프리캐스트 콘크리트 박스 암거는 현장 타설식 암거에 비해 구조물의 고품질화 및 반복적인 대량생산으로 원가 절감과 건식화 시공으로 인한 공정의 단순화와 공기가 단축되는 이점을 지니고 있다. 따라서 본 연구는 상재 허용하중을 확보하고, 시공성 및 내구성이 뛰어나며, 경제성을 고려한 고성능 프리캐스트 박스 암거를 개발하고 향후 고성능 프리캐스트 박스 암거를 생산하기 위한 기초적인 자료를 제시하고자 하였다. 본 연구에서는 기존의 보통 포틀랜드 시멘트를 이용한 프리캐스트 박스 암거의 경제성 및 내구성, 강도특성을 개선하고자 고로슬래그를 이용하여 최적의 배합비를 산출하고, 이를 토대로 중성화, 염해, 동결융해 등의 시험을 통해 내구성을 확보하고, 휨 성능을 확인하고자 실물박스암거를 제작하여 외압강도시험을 실시하였다. 또한 구조해석을 통해 응력검토를 하였다. 내구성 검토 결과, 분말도 $6,000cm^2/g$을 가진 고로슬래그 미분말을 50%로 혼입한 콘크리트가 보통 포틀랜드 시멘트를 사용한 콘크리트보다 염화물이온 투과성에 대한 저항성 및 동결융해 저항성 등 기초물성 및 내구성이 개선됨을 알 수 있었다. 박스암거에 대한 휨 시험 결과, OPC에 비해 GFSC6의 경우는 크게 구조적 성능이 떨어지지는 않는 것으로 나타났으며, 균열양상 및 연성도에서는 우수함을 나타냈다. ABAQUS에 의한 비선형 해석 결과는 시험체의 휨 거동을 잘 묘사하는 것으로 나타났으며, 처짐의 경우 시험체의 시험결과보다 크게 나타났지만, 처짐 양상은 비슷한 것을 알 수 있었고, 벽체와 상부 슬래브에 발생하는 응력은 부재가 허용하는 균열응력값 이내로 나타남에 따라 사용하중 상태에서의 응력검토는 안전한 것으로 판단된다.

• Journal of the Korea Concrete Institute
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• v.23 no.4
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• pp.479-486
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• 2011

In this study, we conducted experiment and finite element analysis on the flexural behavior of the round concrete panels according to the evaluation method of biaxial flexural tensile strengths. The Round Panel Test (RPT) and the Biaxial Flexure Test (BFT) were used to determine the biaxial flexural strength of round plain concrete panels. In order to understand the stress distribution on the panels, we measured load-strain relationship at the center of the panels' bottom surface. Test results show that fracture pattern in RPT and BFT panels are similar, and the tensile stress distribution is uniform in all directions at the center of the bottom surface of the panels for both RPT and BFT. The distribution of stresses in two test specimens coincided with the analysis result. The average biaxial flexural strength of RPT is about 29% greater than those of the BFT. The coefficient of variations (COV) of the RPT and BFT for the biaxial flexure strength is 8%, 6%, respectively, which indicates that BFT method is useful and reliable for determining biaxial flexural strengths of the concrete.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.5
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• pp.551-557
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• 2010

The purpose of this study is to estimate experimentally the flexural behavior, capacity and validity of existing regulation of net tensile strain in lightweight concrete beams and polymer modified lightweight concrete beams. One normal weight concrete beam and four lightweight concrete beams, three polymer modified lightweight concrete beams were constructed as same figure and attempted to evaluate the difference of strength and ductility in specimens of different net tensile strain in extreme tension steel. Test results are indicated in terms of load-deflection behavior and ductility index. As the value of net tensile strain increased, the flexural strength and stiffness of specimen decreased but ductility index increased in both of lightweight concrete beams and polymer modified lightweight concrete beams. It is considered that to achieve similar ductility index of normal weight concrete, net tensile strain in extreme tension steel should exceed 0.005 for lightweight concrete beam and polymer modified lightweight concrete beam.