과거 지진 발생 시 구조요소에 비해 비구조요소에서 더 많은 피해가 발생하였다. 비구조요소의 손상은 건물 및 시설의 기능에 영향을 줄 뿐만 아니라 인명피해를 유발할 수 있다. 건축물 내진설계 기준에서는 피난경로상의 비구조요소는 내진설계 또는 검토가 필요하다. 국내에서는 경주지진 이후 피난경로에 위치할 수 있는 천장 시스템의 내진성능 검증이 활발히 진행되고 있다. 그러나 옥외 계단, 문 등에 설치되는 캐노피 시스템의 내진설계 및 검증은 미흡한 실정이다. 지진으로 인해 캐노피가 위치유지를 하지 못하여 탈락 하거나 손상될 경우, 피난경로가 차단되어 인명피해로 이어질 수 있으므로 내진설계 및 내진성능을 평가할 필요가 있다. 따라서 본 연구에서는 모듈형 캐노피 시스템을 개발하고, 주요 요소에 대한 구조실험을 수행하였으며, 기존의 캐노피 시스템과 그 성능을 비교분 석 하였다.
본 연구에서는 센싱 기반 모니터링 스마트 파이프 개발 연구의 일환으로 화학적 전처리된 코팅 강관에 대한 유한요소해석을 실시 하였다. 개발된 코팅 강관은 내・외면 개질 폴리에틸렌으로 화학적 코팅 전처리 과정을 수행하였으며, 확관 시 표면 코팅 손상을 최소 화하기 위한 연결 부속을 사용한 코팅 강관의 해석을 수행하였다. 다양한 하중에 대한 구조성능 평가를 위해 토압 하중에 의한 정적 구 조해석, 차량 하중에 의한 피로수명 평가, 인장 및 압축 하중에 의한 누수 저항성의 4가지 하중 조건을 설정 및 조사하였다. 해석 결과, 기존 에폭시 코팅 및 조인트 사용 강관 대비 개발 강관에서 개선된 피로 수명이 산출되었으며, 동일 직경의 조건에서 평균 56.1%의 최 대 변위 감소와 61.2% 최대 응력이 감소함을 통해 개발 코팅 강관과 연결 부속의 안전성을 검증하였다. 이에 더하여 응력 분포 분석을 통해 체결부의 누수 저항성 역시 강관 중앙면 대비 우수함을 확인하였다.
유리섬유 또는 바잘트섬유로 만들어진 고성능 복합섬유 패널은 고강도 보강재이지만, 구조보강을 위해 정사각형 또는 직사각형 구조물에 패널을 부착할 경우에 일체형 거동을 확보하기 위해 모서리 패널이 사용된다. 이러한 모서리 패널을 이용한 복합섬유 패널의 볼트 접합부를 통해 일체형 거동을 확인하기 위해 실험을 진행하였다. 실험변수로 연단거리 비, 측단거리 비, 볼트 배치 형태(엇모배치와 일렬배치) 및 전단면 수가 설정되었다. 강도평가에 대한 실험 결과, 볼트직경에 대한 연단거리비가 4이상 권장된다는 것을 확인하였고 이를 확보할 시 지압에 의한 파괴모드를 확인하였다. 또한, 볼트배치 2종류의 파괴하중은 값이 유사하였다.
The purpose of this paper is to improve the inappropriate analysis results when the end of the brace on braced frame is applied as pinned connection in practice. The stiffness of the gusset plate connection on the braced frame has the amount of between pinned and rigid connection, and the analysis model that applies the stiffness of the connection must be used for accurate performance evaluation. In this study, the stiffness of the gusset plate designed by the balanced design procedure are quantified, and applied to the analysis model to simulate the gusset plate connection. The proposed model was verified through nonlinear static analysis (pushover analysis) of SAP2000. The effect of the connection on the seismic performance of the braced frame was analyzed by comparing the proposed model and pinned model. As a result, it was confirmed that the performance of the braced frame was evaluated conservatively in practice, and the ductility was overestimated. Therefore, it is important to consider the connection for accurate and economical performance evaluation.
본 연구의 대상은 도로 폭이 좁은 시가지에서 굴착공사 시 적용되는 장지간 주형의 연결부이다. 일반적으로 적용되고 있는 연결부에서 상부 플랜지의 단차와 피로균열 등의 문제로 연결부의 신뢰도가 저하된다. 연결부의 결함을 보완하고 안전성을 향상시킨 개선형 연결부를 개발하였다. 유한요소 기반의 상용프로그램(ABAQUS)를 이용하여 개선형 연결부의 거동을 평가하였다. 먼저, 개선형 연결부에 적용되는 고장력 볼트 연결 및 강재와 콘크리트의 합성거동을 구현하기 위한 수치해석 방법을 제안하였다. 비교논문의 실험결과와 수치해석 결과의 비교를 통하여 개선형 연결부를 해석하는데 있어 수치해석 방법의 적합성을 검증하였다. 본 연구에서 제 안하는 수치해석 방법을 적용하여 개선형 연결부와 일반형 연결부가 적용된 장지간 주형을 해석하였다. 장지간 주형의 탄소성 거동과 연결부의 응력분포를 수치 해석적으로 비교분석하였다. 개선형 연결부의 도입으로 25%의 압축응력이 감소되며 구조적 성능 개선 효과 및 안전성을 확인하였다.
Recently, for efficiency increase of the wind turbine tower, turbine has been enlarged and installation location has been transferring to offshore. The importance of the support structure is emphasized when a wind turbine tower is installed on offshore. The support structure is influenced not only by the system operating loads but also by various marine condition loads. Accurate and safe design is essential because the connection between the support structure and the wind tower can be relatively fragile. In particular, the type of foundation pile and sleeve grout connection were adapted from DNV, API, and ISO that are typically used for wind towers, and they have been continuously studied by many researchers. However, the experimental results by researchers are different from the design equations, and it needs to modify the formula according to connection properties and material. Therefore, this study investigates the design equation presented in existing design criteria and the results of research conducted by existing researchers, and analyzes ultimate strength and failure modes.
Recently, the fiber reinforced polymers (FRP) materials have been recognized as advanced materials for bridge construction. The FRP bridge deck system has advantages to construct rapidly, its durability. The FRP bridge decks have accepted as a method of deteriorated reinforced concrete bridge deck replacement. For application, design method details and connections for FRP bridge decks will be provided. In this paper, the design method, deck design and connections details on FRP decked precast, prestressed concrete girder bridges is presented. In this study, the design method of efficient connection between FRP deck and concrete girder is proposed with composite action. The schematic of proposed modular FRP panel deck-to-concrete girder connection is also presented, which is the flexible hybrid shear connection included steel reinforcements and FRP tubes. The FRP deck-to-concrete girder hybrid connection system should be improved with further refinement and experimental program. Finally, it is hoped that this paper will be guideline for research and development on this subject field for researchers and engineers
Two types of connection between the abutment and CFT pile were proposed for the sub-structure of the integral abutment bridge. One was a bolt connection (Type-A) and the other was a hook connection (Type-B). To analyze the performance of connection Type-A and Type-B, a quasi-static experiment was carried out. According to experimental results, the destruction occurred at the connection point and so both type A and type B need to have a reinforced design as the link between the abutment and CFT pile. However, when the load resistance performance and energy dissipation capacity was analyzed, the performance of connection Type-B was superior to the performance of connection Type-A.
In this study, a quasi-static experiment was conducted on the connection performance between the integral abutment bridge and CFT pile. Six experiment specimen were manufactured and were divided into type A and type B. Experiment specimens of Type A were connected with bolts and experiment specimens of Type B were connected with hooks. In the experiment results the connection performance of Type B showed excellent performance more than that of Type A.
Grouted connections have been widely used for offshore structures such as connection method of jacket and mono-pile structures. It is recommended high strength concrete for grouting between pile and sleeve because it is so rapidly hardening that helpful to fatigue strength. This study investigates axial strength of pile to sleeve grouted connections made by 130MPa of high strength concrete. Push-out test were performed to evaluate the axial strength of the grouted connections with different shear-key spacing.
Generally, the Load of upper structures is transferred to concrete foundations through columns supporting them. So, the anchor connection system is usually adopted in order to connect the columns and the concrete foundations. To apply this system, the column-foundation connections need to be designed with enough stiffness. This study was experimentally conducted to effectively improve the structural detail of circular CFT column-foundation connections, to which axial and lateral load simultaneously apply. For this study, the test specimen with a general anchor and an anchor frame, and the specimens with the high-tension bolt and inner reinforcement were fabricated. In addition, double base plates were adopted to have the enough stiffness of connections. The behavioral characteristics and the failure mode were investigated and compared, and the improvement of structural detail of circular CFT column-foundation connections was suggested.
Due to the advantageous mechanical properties of the fiber reinforced polymeric plastics(FRP), their application in the construction industries is ever increasing trend, as a substitute of structural steel which is highly vulnerable under hazardous environmental conditions (i.e., corrosion, humidity, etc.). In this study, hybrid FRP-concrete composite pile (HCFFT) connection is suggested. The HCFFT is consisted of pultruded FRP unit module, filament wound FRP which is in the outside of mandrel composed of circular shaped assembly of pultruded FRP unit modules, and concrete which is casted inside of the circular tube shaped hybrid FRP pile. Therefore, pultruded FRP can increase the flexural load carrying capacity, filament wound FRP and concrete filled inside can increase axial load carrying capacity. In the study, connection capacity of HCFFT(small and mid size) is investigated throughout experiments and finite element method. From the results of experiments, we suggested the connection methods about HCFFT pile connection.
In this study, circular sectional concrete-filled tube(CFT) column-to-foundation connections were numerically investigated in order to improve their structural details. A inner reinforced specimen with high-tension bolts and inner deformed bars was adopted from a previous experimental study to make the numerical model. The validity of the numerical method was verified through comparing the experimental results with the analysis’s ones. In order to optimize design variables about the inner reinforced model, a number of numerical analyses were conducted for various variables. Finally, this study suggested the optimum variables about the reinforced circular sectional CFT column-to-foundation connections.