• Steel and Composite Structures
• /
• 제4권3호
• /
• pp.247-263
• /
• 2004

Comparison of behaviour of shear connections by means of shear-connection strips (perfobond and comb-shaped strips) and headed studs under static and repeated loading, possible failure modes of concrete dowels and ways of the quantitative differentiation of some failure modes are described in the paper. The article presents a review of knowledge resulting from the analysis of shear-connection effects based on tests of perfobond and comb-shaped strips carried out in the laboratories of the Faculty of Civil Engineering of the Technical University of Kosice (TU of Kosice) in Slovakia and their comparison with results obtained by other authors.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
• /
• pp.293-296
• /
• 2006

The results and interpretations of push-out tests on shear connector devices for composite bridges carried out in this study are presented. The devices under investigations are headed studes, perfobond rib, ㄱtype perfobond rib, T- Connector and a new type of shear connector called T type perfobond rib. This new connector is flat steel plate with a number of holes punched through. The results obtained indicate that the T type perfobond rib shear connectors exhibit adequate ductility and substantially higher capacities. Therefore for composite beams utilizing reinforced concrete slabs, the T type perfobond rib shear connectors is a viable alternative to the headed studs.

• 한국재난정보학회 논문집
• /
• 제9권4호
• /
• pp.400-412
• /
• 2013

CFT 구조는 내부의 콘크리트와 강관의 합성거동을 위한 전단연결재를 필요로 한다. 하지만, 현행 설계기준에서는 통상적으로 무근콘크리트로 채워지는 CFT 구조에 적용할 수 있는 전단연결재에 대한 설계기준을 제시하고 있지 않다. 본 연구는 강-콘크리트 합성구조에 널리 사용되는 스터드 전단연결재를 CFT 구조에 적용하기 위한 설계기준 즉, CFT 구조에 적용된 스터드 전단연결재의 전단강도를 제안하기 위한 연구의 일환으로 수행되었다. 본 연구에서는 CFT 구조에 적용된 스터드의 전단강도를 결정하는 주된 파괴모드를 검토하기 위하여 무근콘크리트를 적용한 직접전단실험체를 이용하여 실험을 수행하고 파괴모드를 분석하기 위한 유한요소해석을 실시하였다. 직접전단실험 및 유한요소해석결과로부터 CFT 구조에 적용된 스터드 전단연결재의 주된 파괴모드는 콘크리트의 쪼갬파괴이며, 이러한 파괴모드로 인하여 철근콘크리트에 적용된 스터드에 비해 전단강도가 감소한다는 사실을 확인할 수 있었다.

• 전기학회논문지P
• /
• 제65권2호
• /
• pp.101-107
• /
• 2016

The main target in this paper is the localization of VME Type EPSM in Generator Exciter(EX2100) System. Developed EPSM has the compatibility with the existing product in the structure and shape and electrical feature and so on, but it has a much improved capacity and reliability in comparison with origin company product. this paper, to improve these functions, put emphasis on protection, monitoring, power capacity increase(over 120%), an enlarged scale of input voltage supply, AC/DC dual voltage use and so on. After manufacturing product localization, it was carried out several tests for the performance and reliability verification of developed product. These tests were performed in Authorized Inspection Agency(KTL) and field application test and maker self-test were additionally performed. Finally, the results of all tests were "success".

• Steel and Composite Structures
• /
• 제37권5호
• /
• pp.517-532
• /
• 2020

This paper firstly developed a new type of Double Skin Composite (DSC) beams using novel enhanced C-channels (ECs). The shear behaviour of novel ECs was firstly studied through two push-out tests. Eleven full-scale DSC beams with ECs (DSCB-ECs) were tested under four-point loading to study their ultimate strength behaviours, and the studied parameters were thickness of steel faceplate, spacing of ECs, shear span, and strength of concrete core. Test results showed that all the DSCB-ECs failed in flexure-governed mode, which confirmed the effective bonding of ECs. The working mechanisms of DSCB-ECs with different parameters were reported, analysed and discussed. The load-deflection (or strain) behaviour of DSCB-ECs were also detailed reported. The effects of studied parameters on ultimate strength behaviour of DSCB-ECs have been discussed and analysed. Including the experimental studies, this paper also developed theoretical models to predict the initial stiffness, elastic stiffness, cracking, yielding, and ultimate loads of DSCB-ECs. Validations of predictions against 11 test results proved the reasonable estimations of the developed theoretical models on those stiffness and strength indexes. Finally, conclusions were given based on these tests and analysis.

• 한국강구조학회 논문집
• /
• 제17권5호통권78호
• /
• pp.549-559
• /
• 2005

철도교는 강성이 주요한 설계인자이기 때문에 기존의 2거더 교량의 구조적 효율성을 높이기 위해서 이중합성 구조를 가진 철도교를 제안하였다. 일반적으로 강합성 연속교를 설계할 경우, 부모멘트 구간에 존재하는 콘크리트 바닥판은 인장에 저항하지 못한다고 가정하고 바닥판 단면을 무시하게 된다. 부모멘트 구간에서는 합성단면의 강성이 감소하게 되므로 이를 보완하기 위해 강재단면이 커지게 되는데, 이러할 경우 변단면의 적용이 불가피하게 되고 강합성형으로서의 장점이 반감된다고 할 수 있다. 이와 같은 문제점을 해결하기 위한 다양한 접근법이 존재하지만 그 중에서도 경간을 확대하고 강성이 중요한 설계인자가 되는 경우에 적절하게 사용될 수 있도록 제안된 교량의 형태가 이중합성구조이다. 따라서 본 연구에서는 이중합성 전단연결부의 거동을 파악하기 위하여 수평스터드, 수평스터드와 수직스터드가 함께 배치된 복합스터드 부재에 대한 push-out 실험을 수행하였다. 실험결과의 분석을 통하여 기존의 설계식과의 비교를 수행하고 정적 거동을 평가하였다.

• Steel and Composite Structures
• /
• 제36권4호
• /
• pp.369-381
• /
• 2020

Nowadays, in prefabricated composite construction, composite action between steel beam and concrete slab is often achieved with positioning of shear connectors in envisaged openings of concrete slabs. Prefabricated concrete slabs are used for composite steel-concrete buildings and bridges, both for the construction of new structures and for renovation of existing ones, significantly reducing construction time. Development of different types of shear connectors represent alternative solution to the traditionally used headed studs, considering their shear resistance, stiffness and ductility. New types of shear connectors tend to reduce the construction time and overall construction cost. Mechanically fastened shear connectors represent a viable alternative to headed studs, considering their fast installation process and shear resistance. X-HVB shear connectors are attached to the steel beam with two cartridge fired pins. The first step towards extensive implementation of X-HVB shear connectors in composite construction is to understand their behaviour through experimental investigation. Results of the push-out tests, in accordance to Eurocode 4, with X-HVB 110 shear connectors positioned in envisaged openings of prefabricated concrete slabs are presented in this paper. The experimental investigation comprised three different specimen's layout. Group arrangement of X-HVB shear connectors in envisaged openings included specimens with minimal recommended distances and specimens with reduced distances between connectors in both directions. Influence of different installation procedures on overall behaviour of the connection is presented, as well as the orientation of shear connectors relative to the shear force direction. Influence of variations is characterized in terms of failure mechanisms, shear resistance and ductility.

• Steel and Composite Structures
• /
• 제26권4호
• /
• pp.485-499
• /
• 2018

In this paper, a hollow steel tube (HST) shear connector is proposed for use in a slim-floor system. The HST welded to a perforated steel beam web and embedded in concrete slab. A total of 10 push-out tests were conducted under static loading to investigate the mechanical behavior of the proposed HST connector. The variables were the shapes (circular, square and rectangular) and sizes of hollow steel tubes, and the compressive strength of the concrete. The failure mode was recorded as: concrete slab compressive failure under the steel tube and concrete tensile splitting failure, where no failure occurred in the HST. Test results show that the square shape HST in filled via concrete strength 40 MPa carried the highest shear load value, showing three times more than the reference specimens. It also recorded less slip behavior, and less compressive failure mode in concrete underneath the square hollow connector in comparison with the circular and rectangular HST connectors in both concrete strengths. The rectangular HST shows a 20% higher shear resistance with a longer width in the load direction in comparison with that in the smaller dimension. The energy absorption capacity values showed 23% and 18% improvements with the square HST rather than a headed shear stud when embedded in concrete strengths of 25 MPa and 40 MPa, respectively. Moreover, an analytical method was proposed and predicts the shear resistance of the HST shear connectors with a standard deviation of 0.14 considering the shape and size of the connectors.

• 한국지반환경공학회 논문집
• /
• 제15권6호
• /
• pp.75-83
• /
• 2014

석션버켓기초는 펌프로 버켓 내부의 물을 외부로 배출할 때 발생한 압력차로 지반에 설치되는 기초이다. 버켓기초는 외해의 플랫폼이나 석유 가스 시추시설을 계류시키기 위한 앵커로 주로 사용되었으나, 최근 유럽을 중심으로 해상풍력발전의 기초로 적용되기 시작하면서 국내에서도 큰 관심을 받고 있다. 석션버켓기초의 관입저항력 산정은 석션버켓기초를 성공적으로 시공하기위해 고려해야 할 주요 사항 중의 하나이다. 본 연구는 석션버켓기초를 관입시킬 때 필요한 관입력을 평가하기 위해 실내모형실험을 수행하였다. 실내모형실험은 압입설치 및 석션설치에서 측정한 관입저항력을 관입성능평가에서 많이 사용되는 기존의 이론식과 비교하여 강도감소계수의 적절한 범위를 검토하였다.

• Restorative Dentistry and Endodontics
• /
• 제45권2호
• /
• pp.19.1-19.8
• /
• 2020

Objective: This study aimed to evaluate the effect of ultrasonic cleaning of the intracanal post space on the bond strength of fiber posts in oval canals filled with a premixed bioceramic (Bio-C Sealer [BIOC]) root canal sealer. Materials and Methods: Fifty premolars were endodontically prepared and divided into 5 groups (n = 10), based on the type of root canal filling material used and the post space cleaning protocol. A1: gutta-percha + AH Plus (AHP) and post space preparation with ultrasonic cleaning, A2: gutta-percha + BIOC and post space preparation with ultrasonic cleaning, B1: gutta-percha + AHP and post space preparation, B2: gutta-percha + BIOC and post space preparation, C: control group. Fiber posts were cemented with a self-adhesive luting material, and 1 mm thick slices were sectioned from the middle and cervical third to evaluate the remaining filling material microscopically. The samples were subjected to a push-out test to analyze the bond strength of the fiber post, and the results were analyzed with the Shapiro-Wilk, Bonferroni, Kruskal-Wallis, and Mann-Whitney tests (p < 0.05). Failure modes were evaluated using optical microscopy. Results: The results showed that the fiber posts cemented in canals sealed with BIOC had lower bond strength than those sealed with AHP. The ultrasonic cleaning of the post space improved the bond strength of fiber posts in canals sealed with AHP, but not with BIOC. Conclusions: BIOC decreased the bond strength of fiber posts in oval canals, regardless of ultrasonic cleaning.