In this research, the concrete breakout strength in tension of cast-in-place anchors (CIP) is experimentally investigated to be used as fundamental data for the seismic fragility analysis of equipment in nuclear power plants. Experimental variables are chosen, such as the embedment depth of the anchor, single/group anchor configurations, diameter of the head plate, and crack width. Monotonic and cyclic loading are applied to all types of specimens. As measured from the experiments, concrete breakout strength in tension is 1.5 to 2 times higher than the expected strengths from concrete capacity design (CCD) method-based model equations. In alignment with the model’s predictions, concrete breakout strength increases with deeper embedment depth, and the strength of group anchors also increases based on the expansion of the projected concrete failure area. This study also explores the effects of head plate diameter and crack width, which are not considered in the model equation. Experimental results show that the diameter of the head plate is not directly correlated to the concrete breakout strength, whereas the crack width is. The presence of cracks, with widths of 0.3 mm and 0.5 mm, leads to reductions of approximately 7% and 17%, respectively, compared to single anchors in non-cracked concrete.

강재를 대처할 수 있는 다양한 복합재료 중 CFRP (Carbon Fiber Reinforced Polymer)를 사용하여 인장 물성 실험을 실시한다. KS F ISO 10406 (콘크리트용 섬유강화 폴리며(FRP 보강재 - 시험방법) 에서 FRP의 측정길이는 지름 (D)의 40 배를 기준으로 제시되어진다. 그러나 25 mm 이상의 시험체는 양단 보강부를 포함하게 된다면 대략 2 m 이상으로 제작되어지게 되고 시험이 상당히 번거롭게 됨으 로써 시험법 개선을 위해서 측정 길이별로 설정하여 성능평가 후 비교분석 한다.

For the practical application of U-flanged Truss Hybrid beams, the flexural capacity of hybrid beams with end reinforcement details using vertical steel plates was verified. The bending test of U-flanged Truss Hybrid beams was performed using the same top chord under the compressive force, but with the thickness of the bottom plate and the amount of tensile reinforcement. The initial stiffness and maximum load of the specimen with tensile reinforcement have a higher value than that of the specimen without tension reinforcement, but the more tensile reinforcement, the greater the load decrease after the maximum load. In the case of the specimen with tensile reinforcement, because the test result value is 76% to 88% when compared with the flexural strength according to Korea Design Code, the safety of the U-flanged Truss Hybrid beam with the same details of the specimens can’t ensure. Therefore, the development of new details is required to ensure that the bottom steel plate and the tensile reinforcement can undergo sufficient tensile deformation.

과거에는 건축물의 지하구조물은 지반에 둘러싸여있어 지진이 발생했을 때 지반과 함께 움직이기 때문에 지진에 대한 내진설계가 요구되지 않았다. 하지만, 지진에 대한 사례분석과 연구결과를 바탕으로 지하구조물에도 내진설계가 필요하다는 결론에 도달하였다. 또한, 기존 건축구조기준의 건축물에 대한 내진설계에서는 지하구조물에 대한 내진설계조항이 명확히 규정 되어 있지 않았으나, 지하구조물 내진설계 기준이 포함된 KDS가 시행됨에 따라 횡력에 저항할 수 있는 보-기둥 접합부의 수요가 증가할 것으로 예상된다. 강관기둥에 사용되는 보-기둥 접합부는 보에서 기둥으로 하중을 전달하기 위해서 다이어프램을 설치하는 형태의 접합부가 일반적이다. 이때 설치되는 다이어프램은 제작성 및 시공성을 저하시키며, 지하구조물 공법과 적합성이 맞지 않아 시공시 많은 문제점이 있다. 이러한 문제점을 해결하기 위해서 이 연구에서는 다이어프램을 설치하지 않고 기둥의 두께를 증가시켜 보에서 기둥으로 하중을 전달하는 접합부 3개와 삼각형 유닛을 조립하여 제작한 접합부 1개를 제작하여 인장력을 전달하는 실험적 연구를 수행하였다. 실험결과는 구조기준에서 제시하고 있는 집중하중이 작용하는 강관의 강도와 비교하여 분석하였다.

To fabricate the 5182 aluminum-polymer sandwich panels, the strength of 5182 aluminum panels, which are the skin sheets that constitutes the sandwich composite panels, is changed according to the degree of heat treatment after rolling, and the characteristics of sandwich panel are also changed. In addition, in the stress-strain curves of the sandwich panel, the serration behavior observed in the 5182 aluminum alloy sheet is also observed. This serration behavior causes surface roughness during sheet forming, which is a serious problem in application to automotive body sheet. In this study, the tensile properties of the 5182 aluminum sandwich panels at room and elevated temperature were carefully investigated by tensile test. It can be found that when the aluminum surface sheets having insufficient heat treatment time is applied, the serration behavior does not completely disappear from the temperature of the room temperature to 160℃.

The BX composite beam is designed to have the same cross-section regardless of the size of the momentum, which is a disadvantage of the existing steel structure. Combination of the H-beam end compressive material and the H-section steel tensile reinforcement according to the moment size in a single span, It is possible to say that it is an excellent synthesis which increases the performance. When underground and overhead structures are constructed, it is possible to reduce the bending, increase lateral stiffness, reduce construction cost, and simplify joints. The seamability of the joining part is a simple steel composite beam because of the decrease of the beam damping at the center of the beam and the use of the end plate of the new end compressing material. In the case of structures with long span structure and high load, it is advantageous to reduce the material cost by designing large steel which is high in price at less than medium steel.

As buildings are becoming larger, demand for large-scale composite columns for heavy load is increasing. Welded built-up CFT column (ACT Column I) previously developed by authors of this study is structurally stable and economical. Characteristic of welded built-up CFT column is that there is a limitation of cross-sectional size and application of external diaphragm connection to ensure continuity of rib. Then, composite mega column (ACT Column II) was developed to improve limit of cross-sectional size. Composite mega column has a closed cross section like welded built-up CFT column, but thick plate is inserted between cold-formed steel to expand cross section size. However, when external diaphragm connection is applied to composite mega column, amount of steel is increased greatly and interference with finishing material occurs. In this study, internal diaphragm connection is applied through characteristic of composite mega column to which beam flange or stiffener can be attached to plate. In order to analyze this, simple tensile experiment of composite mega column connection with T-shaped stiffener was performed.

Tensile strength was investigated for hybrid bar (HYB), in this study. HYB is made of both steel reinforcement and glass fiber. Cross section of HYB has a shape in which steel reinforcement wrapped with glass fiber. For the production of HYB, rebar of SD400 class and glass fiber of E class are used as main materials. Vinyl ester resin is used to harden a glass fiber. In order to evaluate for tensile strength of HYB, the direct tensile test was performed about total ten specimens. The length of total specimens is 2,200 mm including the grip. Diameter of HYB according to core diameter was considered as a test variable. Direct tensile test for HYB was performed using a UTM with a capacity of maximum 1,000 kN. Tensile strength and strain were measured for each specimen during the test. From the test results, tensile strength and elastic modulus were 317 ~ 341 MPa, 103 ~ 107 GPa, respectively. Especially, elastic modulus of HYB was improved in comparison with usual GFRP bars such as the Aslan 100 or the V-rod.

본 연구는 경상남도 하동군 옥종면 땅밀림 산사태지의 붕괴지 및 피해지역을 중심으로 사면붕괴양상을 규명하기 위해 땅밀림 산사태지의 인장균열지의 월별 변화양상을 조사하였다. 그 결과, 연구대상지에서는 땅밀림 산사태 발생징후라 판단되는 지하수 용출, 융기 및 함몰, 수목이상성장 등이 발견되었다. 아울러 당초 인장균열 두께와 폭은 1 : 4.2, 폭과 길이는 1 : 1.5로 나타났으며, 월평균 인장균열의 증감 폭은 폭 > 길이 > 상단부 사면길이 > 단차 순으로 나타났다. 한편, 강우인자와 인장균열의 형태 및 인장균열의 형태 중 세부인자들 간의 상관분석을 실시한 결과, 모두 상관관계가 없는 것으로 나타났다.

These days, the Composite Slabs with Deep Deck plate was commonly used in domestic construction site, and, the application of the Slim Floor system was increased from the Enlargement and High-rise Building. But, Slim Floor system using the Deep Deck was shown safety problem caused by the deflection and local buckling in construction phase when used to more than 6m. Therefore, for solving the problem, the installation of the shores is essential. This study is realize the long span slab without shores from control the deflection through applied the pre-tensioning elements in CAP deck. In addition, by applying the pre-tensioning member as the tensile member of the CAP Deck slab, the pre-tensioning member for the shores tries to be used as the structural member. Accordingly, to determine the flexural performance of the CAP Deck slab through the pre-tensioning force in tensile member, and, the composite effect of the CAP Deck slab by the experiments.

Until recently, almost all ETFE film structures that have been erected is the cushion type because there are problems at lower allowable strength under elastic range and viscosity behaviour such as creep and relaxation of ETFE films under long-term stresses. But the number of tension type structures is currently increasing. This paper proposes the stretch fabrication of ETFE film to verify the applicability of ETFE films to tensile membrane structures. First of all, to investigate the possibility of application on tensile membrane structures, the stretch fabrication test is carried out, and it is verified that it is possible to increase the yield strength of the film membrane structures. After simulating the experiment also carries out an analytical investigation, and the effectiveness of the elasto-plastic analysis considering the viscous behavior of the film is investigated. Finally, post-aging tension measurement is conducted at the experimental facilities, and the viscosity behavior resulting from relaxation is investigated with respect to tensile membrane structures.

These days, the Composite Slabs with Deep deck plate was commonly used in domestic construction site, and, the application of the Slim Floor system was increased from the Enlargement and High-rise Building. But, Slim Floor system using the deep deck was shown safety problem caused by the deflection and local buckling in construction phase when used to more than 6m. Therefore, for solving the problem, the installation of the shores is essential. This study is realize the long span slab without shores from control the deflection through applied the pre-tensioning elements in cap deck. In addition, by applying the pre-tensioning member as the tensile member of the Cap Deck composite slab, the pre-tensioning member for the shores tries to be used as the structural member. Accordingly, to determine the flexural performance of the Cap deck composite slab through the pre-tensioning force in tensile member, and, the composite effect of the cap deck composite slab by the experiments.

The seismic design range for the national public facilities and power plant is expanded such as it becomes the earthquake Disaster Relief Act with the finance since 2008 as the seismic design concept is highly regarded, etc. The reinforcement of the brace is essential for the seismic performance security of the structure which is unable to be satisfied the current seismic design criteria. The tension brace in which the slenderness ratio is big was designed to the unique lateral force resistive element. And the buckling is generated in the first stage and it is unable to exhibit the structural capability. In this research, the buckling strength improvement the reinforcing method of the suggested tension brace tries to be verified through the experiment.

본 연구는 실험계획법(예: 반응표면계획법) 및 하모니 검색 알고리즘을 통하여 다양한 아스팔트 콘크리트 포장 구조체에 있어 피로균열의 공용성 인자인 인장변형률을 예측하는 모델을 개발하는 방법에 대한 연구이다. 인장변형률을 산정하기 위하여 한국건설기술연구소에서 개발한 유한요소 축대칭해석 프로그램인 KICTPAVE를 이용하여 아스팔트 층과 린콘크리트 층의 접속면에서 발생되는 변형률을 구하여 데이터베이스(D/B)화 하였다. 아스팔트 포장에서 입력변수인 층별 탄성계수 및 두께를 다양한 조건에서 KICTPAVE 프로그램을 수행하여 훈련용 D/B(Training Set)인 변형률의 값들을 구축한 후 반응표면계획법에 근거하여 회귀방정식을 정의하였으며 방정식에 필요한 계수값을 결정하기 위하여 하모니 검색 알고리즘을 이용하였다. 최종적으로 결정된 회귀방정식의 계수값들의 정확성을 검증하기 위해서 훈련용 D/B가 아닌 다른 조건의 입력변수를 이용하여 검증용 D/B(Testing Set)를 구축하고 이를 이용하여 개발된 모델을 검증하였다.