콘크리트에 표면매입 보강된 FRP판의 전단키 및 연단거리 효과

서수연 한국구조물진단유지관리공학회 2016 한국구조물진단유지관리공학회 논문집 Vol.20 No.1

본 연구에서는 콘크리트에 표면매입된 FRP판의 부착거동에서, 전단키와 연단거리의 효과를 관찰하기 위한 부착시험을 실시하였 다. 실험에서의 주요변수는 전단키의 위치, 형태 그리고 연단길이이다. 규격 3.6 ㎜×16 ㎜의 FRP를 400 ㎜×200(300) ㎜×400 ㎜ 규격의 콘크리 트 블록에 매입하고 에폭시로 고정시켜서 실험변수에 따라 총 10개의 부착실험체를 제작하였다. FRP의 연단에 인장력을 가한 뒤 파괴시까지 실험을 실시하고 하중을 기록하였으며, 미끄러짐과 FRP의 인장변형량을 기록하였다. 실험으로부터, 전단키의 위치는 가력부에서 멀리 떨어 질수록 전단강도가 상승하는 것으로 나타났으며, 전단키의 직경이 커질수록 내력이 저하되는 것으로 나타났다. 특히 전단키가 일정 이상의 규 격이 되면 전단키가 없는 경우에 비하여 내력이 저하되어 오히려 부착강도에 부정적인 영향을 미칠 수 있는 것으로 나타났다. NSM FRP에서 응력장용방향의 연단거리가 길어짐에 따라 동일 부착길이임에도 불구하고 내력이 일부 증가하는 것으로 나타났다. 표면매입 보강된 FRP의 부착실험에서, FRP와 콘크리트사이의 부착-미끄러짐은 전체거동을 지배하는 것으로 나타나므로 이에 따른 과도한 미끄러짐은 설계에 반드시 고려될 필요가 있다. This paper presents a bond test to find the effect of shear key and edge length from the bonded FRP in near surface-mounted(NSM) retrofit using FRP plate. Main parameters in the test are the location and size of shear key and the edge length. For the test, 10 specimens were made by embedding FRP plate of 3.6 ㎜×16 ㎜ into 400 ㎜×200(300) ㎜×400 ㎜ concrete block and fixing it by using epoxy. Tensile load was applied to the FRP of the specimens until failure and was recorded at each load increase. In addition, the bond slip and elongation of FRP were measured during the test. From the test, it was found that the further the shear key located from the loading, the higher strength we could get. The bond strength inversely depended on the size of shear key. Especially, when the size of shear key was to be lagger than certain size, the bond strength decreased to very low value; even less than that of the case without shear key. The bond strength somewhat increased corresponding to the increase of edge length from the bonded end of FRP to loading in spite of same bond length. The bond-slip between FRP and concrete governed overall deformation in the bond test of NSM FRP so that the effect of excessive slip is necessary to be considered in the design.

특수전단벽 연결보의 대체상세 실용화 연구

서수연 한국콘크리트학회 2014 한국콘크리트학회 학술대회 논문집 Vol.2014 No.10

비정형데이터를 활용한 코로나-19 팬데믹 이후 화장품 소비트렌드에 관한 연구

서수연,이명주,최에스더 한국미용학회 2022 한국미용학회지 Vol.28 No.6

This study conducted unstructured big data analysis to confirm consumers' perception of cosmetics in the face of increasing non-face-toface consumption due to COVID-19 pandemic. To this end, keywords related to cosmetics were collected through portal sites such as Naver, Daum, and Google using the social network matrix program called Textom. The collection period was set from Jan 2020 to DEC 2021, and a total of 18,672 keywords were collected, and a total of 60 keywords were used for the study by refining unnecessary keywords. The results are as follows. First, performing frequency, TF-IDF analysis, important keywords such as skin, basic makeup, recommendation, use, and brand were presented. Next, semantic network analysis showed that degree centrality was skin, basic makeup, recommendation, use, and brand, closeness centrality was CHANEL, authentication, export, and customize, betweeness centrality was skin, use, brand, products, and basic makeup. Finally, CONCOR analysis resulted in a cluster of five groups: cosmetic attributes, ingredients, products, sales, and using cosmetics. These analysis results confirm consumer perceptions related to cosmetics, key components and sales channels for cosmetics In addition, it is judged that it will propose meaningful implications for establishing effective data presentation and marketing strategies for research related to demand for cosmetics after COVID-19 pandemic.

아동의 건강행태 실태와 건강증진활동 실시 전·후 향상비교 신체활동을 통한 신체적·정서적 상태 변화 중심으로

서수연,신혜선,이종민 초록우산 어린이재단(구 한국복지재단) 2017 어린이재단 발간물 Vol.2017 No.1

전단경간비에 따른 합성지하벽의 거동과 접촉면의 조건을 고려한 유한요소 해석

서수연 한국구조물진단유지관리공학회 2011 한국구조물진단유지관리공학회 논문집 Vol.15 No.6

본 연구의 목적은 전단경간비에 따른 합성지하벽의 거동을 실험적으로 연구하고 유한요소해석 프로그램인 ADINA를 활용 하여 합성지하벽 (Composite Basement Wall, CBW)의 비선형 거동의 예측이다. 특히 각 층 바닥 부근과 같이 콘크리트가 압축응력상태일 때의 합성벽의 거동을 연구하였다. 특히 강재와 콘크리트가 접촉되는 부분의 모델링 방법에 따른 해석방법의 적합성을 검토하고자 하였다. 콘크리트 벽체부분이 압축응력상태에 있는 합성지하벽의 거동을 이해하기 위하여 합성지하벽에 대한 실험을 실시하고 ADINA 프로그램을 이용하여 유한요소해석을 실시하였다. 해석의 편의를 위하여, 철근은 별도의 독립 요소로 모델링하지 않고, 콘크리트에 등분포되어 콘크리트와 함께 거동하는 것으로 하고 모든 요소는 소성거동을 표현하기 위하여 이선형 모델로 하였다. 강재와 콘크리트의 접촉면과 관련해서는 접촉면의 연결조건에 따라, AGO, SEGO-T 그리고 SEGO-NT로 모델링하여 해석을 실시한 뒤 각 조건에 따른 응력흐름과 집중정도를 관찰하고 그 결과를 실험결과와 비교하였다. 연구결과, 합성지하벽은 전단경간비가 비록 1에 가깝더라도, 강재의 소성변형에 의해 충분히 연성적인 거동을 보이는 것으로 나타났으며, 이와 같은 거동을 묘사하기 위하여 ADINA 프로그램을 이용하여 콘크리트와 강재 및 스터드볼트의 비선형특성을 고려하고 접촉면 요소로서 강재와 콘크리트의 접합면을 모델링하여 해석한 결과 접촉면연결과 모든 절점공유 옵션을 사용한 모델을 적용할 경우, 실험결과와 근사한 예측이 가능한 것으로 나타났다. The objective of this paper is to study the structural behavior of Composite Basement Wall (CBW) according to shear span-to-depth ratio through an experiment and predict the nonlinear behavior of CBW by using ADINA program widely has been being used for FE analysis. Especially, this study focuses on the part of CBW in which the Reinforced Concrete (RC) is under compression stress; At the region of CBW around each floor, RC part stresses by compressive force when lateral press by soil acts on the wall. The contact condition between RC wall and steel (H-Pile) including stud connector is main factor in the analysis since it governs overall structural behavior. In order to understand the structural behavior of CBW whose RC part is under compressive stress, an experimental work and finite element analysis were performed. Main parameter in the test is shear span-to-depth ratio. For simplicity in analysis, reinforcements were not modeled as a seperated element but idealized as smeared to concrete. All elements were modeled to have bi-linear relation of material properties. Three type of contact conditions such as All Generate Option (AGO), Same Element Group Option with Tie(SEGO-T) and Same Element Group Option with Not tie(SEGO-NT) were considered in the analysis. For each analysis, the stress flow and concentration were reviewed and analysis result was compared to test one. From the test result, CBW represented ductile behavior by contribution of steel member even if it had short shear span-to-depth ration which is close to “1”. The global composite behavior of CBW whose concrete wall was under compressive stress could be predicted by using contact element in ADINA program. Especially, the modeling by using AGO and SEGO-T showed more close relation on comparing with test result.

기둥형상과 보 깊이 변화에 따른 외부 기둥-넓은 보 접합부의 이력거동에 관한 연구

서수연,윤승조,윤용대 대한건축학회 2007 大韓建築學會論文集 : 構造系 Vol.23 No.3

In wide beam, how the effective width is decided is very important since the calculation of stiffness and strength of the beam is based on it. Several research works have been conducted by previous researcher to find the effective width of wide beam. And also New zealand code prescribes a formula to calculate it. However these didn't consider the effectiveness of spandrel beam in exterior joint, which affects the behavior of wide beam. In this study, therefore, an evaluation on seismic resistance capacity of the exterior column-wide beam joint with spandrel beam is performed. Five specimens are designed to have variable test parameters; that are column width, column depth and the beam depth. Cyclic loads are applied to the beam end of test specimen according to the test procedure suggested by ACI committee. Before the test, previous formula to calculate the effective of wide beam were reviewed and the strength of specimens was predicted by using these. From the test, it was found that the ultimate strength of specimen linearly increased when the beam or column depth increased; the variation of column depth was more sensitive to the strength of specimens. The comparison result by using previous formula in predicting the strength of specimen shows that most close prediction can be possible when uses Wight's one. Other two formula codified in ACI or New zealand code underestimate test results.

충전각형강관 말뚝과 합성된 건물 지하벽의 휨강도 평가

서수연,이병희 대한건축학회 2022 대한건축학회논문집 Vol.38 No.9

In this study, a design method for estimating the flexural strength of a composite underground wall in which a filled square tube pile and a building basement wall were combined was presented. When earth pressure is applied to the composite basement wall, most of the earth pressure is transmitted to the building wall through low-rigidity piles not combined with the basement wall. Flexural deformation between the two members occurs due to the difference in the flexural stiffness between the not combined pile and the basement wall. Accordingly, since tensile stress as well as shear stress along the interface are generated in the shear connector. An flexural strength calculation process that could reflect the state of the interface of the joint was presented and compared with actual experimental results in this paper. As a result, when the composite ratio was less than 100%, it was found that the filled square steel tube pile and the RC wall behaved completely independent under the consideration of the joint opening. In this case, the sum of each independent flexural strength was found to be close to the actual experimental results rather than the flexural strength by composite action. The calculated moment showed good correspondence with the experimental results. Therefore, through this calculation process, it is possible to predict the flexural strength of the composite basement wall in case opening deformation occurs between the filled square tube pile and the RC wall. 본 연구에서는 충전각형강관 말뚝과 지하건축벽이 결합된 합성지하벽의 휨강도 산정을 위한 설계방법을 제시하였다. 합성지하벽에 토압작용시 토압의 대부분은 낮은 강성의 비합성된 말뚝들을 통하여 건축벽으로 전달되므로 말뚝과 건축벽의 휨강성 차이에 의해 두 부재 사이에는 벌어짐 변형이 발생한다. 이에 따라 전단연결재에는 계면을 따른 전단응력뿐만 아니라 인장응력이 발생하게 되므로 이와 같은 접합부 계면의 상태를 반영할 수 있는 휨강도 계산과정을 제시하고 실제 실험결과와 비교하였다. 그 결과 계산된 내력이 실험결과와 좋은 대응을 보이는 것으로 나타났다. 따라서 이 계산과정을 통하여 충전강관말뚝과 RC벽이 사이에 벌어짐변형이 발생할 경우의 합성지하벽 휨강도를 적절히 예측할 수 있을 것으로 판단된다.

FRP판을 이용한 콘크리트 보강에서 보강방법에 따른 부착성능

서수연,오재길,최기봉,Seo, Soo-Yeon,Oh, Jae-Gil,Choi, Ki-Bong 대한건축학회 2011 대한건축학회논문집 Vol.27 No.8

Recently, FRP (Fiber Reinforced Polymer) has been widely applied in retrofit of concrete member owing to its ease construction and high structural capacity compared to other materials. External Bond Retrofit (EBR) using FRP sheet or plate is most popular method for flexural retrofit of concrete member. In strengthened concrete member using this method, however, problems such as dismantling of FRP were founded after retrofit. This causes a strength reduction of the retrofitted member. To resolve this problem, Near-Surface-Mounted Rertofit (NSMR) method was developed and being studied. In this paper, bond capacities of EBR and NSMR using FRP plate were studied experimently and results were compared each other. Main variables in the test were retrofit method, bond length and existence of shear key. From the test results, it was found that the member strengthened by NSMR had almost 1.5 times higher bond strength than that by EBR. The contribution of shear key was not observed when the splitting failure of concrete governed.

다중이용시설에서 미세먼지(PM<SUB>2.5</SUB>) 측정방법 연구

서수연,장성기,유주희,김현도 한국대기환경학회 2010 한국대기환경학회 학술대회논문집 Vol.2010 No.5월

Longitudinal Course of Depression Scores with and without Insomnia in Non-Depressed Individuals: A 6-Year Follow-Up Longitudinal Study in a Korean Cohort

서수연 AMER ACAD SLEEP MEDICINE 2013 SLEEP Vol.36 No.3