벽식 구조체 적용을 위한 구조용단열패널 성능 평가

나환선,이현주,이철희,황성욱,조혜진,최성모,Nah, Hwan-Seon,Lee, Hyeon-Ju,Lee, Cheol-Hee,Hwang, Sung-Wook,Jo, Hye-Jin,Choi, Sung-Mo 한국복합신소재구조학회 2012 복합신소재구조학회논문집 Vol.3 No.2

Structural insulated panels, which are structurally performed panels consisting of a plastic insulation bonded between two structural panel facings are one of emerging products with a viewpoint of its energy and construction efficiencies. These components are applicable to fabricated wood structures. By now, there are few technical documents regulated structural performance and engineering criteria in domestic market. This study was conducted to suggest fundamental reports such as racking resistance, axial capacity, transverse load capacity, and lintel load capacity for SIPs. Test results showed that maximum load was 44.3kN, allowable load was 14.7kN for racking resistance, and that maximum load was 137.6kN, allowable load was 37.4kN/m for axial compression capacity. For transverse load capacity, test results showed $10.3kN/m^2$ of maximum load, $3.4kN/m^2$ of allowable load. For lintel load capacity for SIPs dependent to lengths, allowable loads were 20.4kN for 600mm long lintel, 23.9kN for 1,200mm long lintel, 19.3kN for 1,800mm long lintel, and 2,400mm long lintel had 14.1kN of allowable load. In the near future, when the allowable load for wall application is established, SIPs is considered to substitute the existent post-and-lintel construction to bearing wall structure.

온도변수에 따른 고력볼트 체결력 평가

나환선,이현주,김강석,김진호,김우범,Nah, Hwan Seon,Lee, Hyeon Ju,Kim, Kang Seok,Kim, Jin Ho,Kim, Woo Bum 한국강구조학회 2008 韓國鋼構造學會 論文集 Vol.20 No.3

건축공사 표준시방서에서 규정하는 TS고력볼트는 KS B 2819에 따라 토크관리법에 의한 체결한다. TS고력볼트는 핀 테일이 파단되면 적정축력이 도입되는 것으로 알려져 있지만, 실제로는 온도조건에 따라 토크계수가 변하고 도입축력도 설계기준에 미치지 못하는 경우가 발생한다. 본 논문에서는 현장 온도조건이 볼트의 토크계수 및 도입축력의 영향을 평가하기 위해 ${-10^{\circ}C{\sim}50^{\circ}C}$ 범위에서 3 종류의 고력 볼트에 대해 도입축력, 토크계수, 너트회전각을 실험적으로 비교 분석하였다. 실험결과 TS고력볼트의 경우 핀 테일이 파단될 때 모든 온도조건에서 설계볼트장력과 표준볼트장력을 상회하는 도입축력을 나타냈으며 ${-10^{\circ}C}$에서 ${50^{\circ}C}$까지 온도 상승함에 따라 핀 테일 파단시점의 볼트에 도입되는 평균축력은 20kN 증가되었다. 아연피막 처리한 일반육각형 고력볼트의 경우, $0^{\circ}C$, $20^{\circ}C$, $50^{\circ}C$조건, 토크계수 0.13과 토크 ${462N{\cdot}m} $에서 표준볼트축력을 상회하였지만, 도입축력의 일정한 경향을 찾을 수 없었으며 온도변수 별 평균 도입축력 차는 최대 50kN이었다. 일반 육각고력볼트의 경우, 온도상승에 따라 평균 도입축력도 상승되는 추세였으며 토크 ${462N{\cdot}m} $ 일때 온도변수별 볼트의 도입축력은 최대 33kN 차이를 보였다. 또한, TS볼트를 제외한 육각볼트 종류 군에 대해서는 너트회전각 ${90^{\circ}}$ 경우의 도입축력은 설계볼트장력에 미치지 못했다. 따라서, 기존 너트회전각 ${120^{\circ}{\pm}30^{\circ}}$의 하한치 ${-30^{\circ}}$에 대한 재평가를 고려해 볼 필요가 있다. The clamping of torque shear bolt is based on KS B 2819. It was misunderstood that the tension force of the TS bolt was induced generally at the break of pin-tail specified. However, the clamping forces on slip critical connections do not often meet the intended tension, as it considerably varies due to torque coefficient dependent on temperature variables despite the break of the pin tail. In this study, the tension of torque shear bolts were compared with two types of high-strength hexagon bolts by temperature parameters from ${-10^{\circ}C}$ to ${50^{\circ}C}$. Torque shear bolts showed that the average clamping force increased to 20kN as the temperature increased. In case of galvanized high-strength hexagon bolts, the average clamping forces at $0^{\circ}C$, $20^{\circ}C$, $50^{\circ}C$ were recorded over standard bolt tension, 178kN, and the worst standard deviation was 50kN. In case of high-strength hexagon bolts, ave rage clamping forces increased as the temperature went up, and the worst standard deviation was 33kN lower than that of galvanized high-strength hexagon bolts. As for the turn-of-the-nut method, at nut rotation of ${90^{\circ}}$, two types of high-strength hexagon bolts did not met the intended design bolt in tension, 162kN.it is neccessary to re-evaluate the range of turn of nut, ${120^{\circ}{\pm}30^{\circ}}$.

미끄럼 표면 도막두께변수에 따른 고력볼트 장기축력 예측

나환선,이현주,류재용,최성모,Nah, Hwan-Seon,Lee, Hyeon-Ju,Ryoo, Jae-Yong,Choi, Sung-Mo 한국복합신소재구조학회 2012 복합신소재구조학회논문집 Vol.3 No.1

고력볼트의 초기 체결력은 미끄럼표면조건에 따라, 일정시간이 경과될 때까지, 축력저하가 발생한다. 이 연구는 미끄럼접합부 표면에 도장이 되어있는 경우, 도장의 크리프현상에 따른 축력저하에 관한 예측 모델을 찾는 것이다. 이 실험연구 범위는 무기질 아연 프라이머로 도포된 볼트접합부의 장기축력저하에 한정한다. 실험에 적용된 볼트종류는 다크로 도포된 토크쉬어 볼트이다. 대상 표면의 도막 두께는 각각 96, 168, $226{\mu}m$ 이었다. 도막두께가 증가될수록, 초기 체결이후 축력이완율은 도막의 크리프 때문에 10%에서 18%로 증가되었다. 장기축력예측을 위한 정량적인 모델은 도막두께에 따른 크리프 스트레인과 경과된 시간사이에 회귀분석 결과로 얻어진다. 이 실험연구를 통해 미끄럼표면 도막의 크리프 거동특성을 알 수 있다면, 일정시간 경과후 고력볼트 체결력은 초기 체결력으로부터 구할 수 있다. 본 실험결과를 근거로 각 도막두께에 대한 장기축력이완이후의 고력볼트 체결력에 관한 정량적인 수식을 제안하였다. The initial clamping forces of high strength bolts depending on different faying surface conditions drop within 1,000 hours regardless of loading, any other external force or loosening of the nut. This study is focused on an expectation model for relaxation of high strength bolt, which is confined to creep on coated faying surfaces after initial clamping. The range of this experiment is limited to estimate the relaxation of bolted joints coated by inorganic zinc primer. The candidate bolts were dacro-coated tension control bolts. The parameters of coated thickness for the faying surface were 96, 168,and $226{\mu}m$ respectively. From experiments, it exhibited that the logarithmic function for creep strain was derived due to the parameter of coating thickness. By using the creep strain, subsequently the quantitative model for estimating long term relaxation of high strength bolt can be taken with the elapsed time. The experimental results showed that the relaxation after the initial clamping of high strength bolt rose to a much higher range from 10% to 18% due to creep of the coating as the coating thickness was increased. This study showed that the clamping force reflecting relaxation after the elapse of constant time can be calculated from the initial clamping force of high strength bolt.

부착력과 임피던스를 이용한 에폭시 도장재 열화 특성에 관한 실험적 평가

나환선 ( Nah Hwan-seon ),김노유 ( Kim Noh-yu ),권기주 ( Kwon Ki-joo ),송영철 ( Song Young-chol ) 한국구조물진단유지관리공학회 2003 한국구조물진단유지관리공학회 논문집 Vol.7 No.2

The purpose of this paper is to quantitatively investigate aging state of epoxy coating on containment structure at nuclear power plant. In order to evaluate an physical bonding of the epoxy coating, adhesion test was performed on a degraded epoxy coating on concrete specimens fabricated by accelerated aging experiment. In addition, impedance data by ultrasonic test were measured to compare with adhesion data. From almost 50 % of the specimens, aging phenomena of epoxy coating such as pin hole, blistering was discovered. To improve reliability on quality degradation of epoxy, co-relation between two kinds of different data was analyzed. By tracing co-related these data, it was possible to figure out physical state of as-built epoxy coating. The possibility to develop new methodology of time - dependent aging state on epoxy coating was found and discussed.

에폭시 도장재의 정량적 열화도 평가를 위한 실험적 연구

나환선 ( Nah Hwan-seon ),김노유 ( Kim Noh-yoo ),송영철 ( Song Young-chol ) 한국구조물진단유지관리공학회 2001 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.5 No.1

The purpose of this study is to quantitatively evaluate the aging status of epoxy coating onto containment structure in nuclear power plant. Based on accelerated aging experiment for 64 days, both adhesion test data and impedence data by UT were received per each six step as time goes. By searching for compatibility between two kinds of different data, physical aging situation of as-built epoxy coating was figured out. The possibility to develop new methodology of time-dependent aging status on epoxy coating was identified.

철근 기계적 이음된 콘크리트 보의 휨파괴 거동

나환선 ( Nah Hwan-seon ),서용표 ( Suh Young-pyo ) 한국구조물진단유지관리공학회 2005 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.9 No.2

The purpose of this research is related to evaluate the flexural behavior of reinforced concrete beam main re-bar mechanically spliced by parallel threaded coupler. To compare the existent lapping method with newly designed mechanical lapping method, five kinds of concrete beam specimens based on several kinds of lapping 22mm diameter re-bar are tested to be failed flexurally by cyclic loading. The relation between load and displacement, ductility, maximum load was comparatively analyzed, according to test results, energy dissipation capacity of flexural specimen mechanically spliced by parallel threaded coupler is 1.6 times greater than that of the other flexural specimens. The ductility of specimen mechanically spliced by parallel threaded coupler is at least 2 times better than concrete specimen with lap spliced re-bar.

초음파 탐상 검사를 이용한 에폭시 도료의 열화 평가

나환선 ( Nah¸ Hwan-seon ),서용표 ( Suh¸ Yong-pyo ),송영철 ( Song¸ Young-chol ) 한국구조물진단유지관리공학회 2000 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.4 No.2

The purpose of this study is to quantitatively evaluate the aging status of epoxy coating onto containment structure in nuclear power plant. Prior to main accelerated aging test, pre-test under short term acceleration was performed to identify the reliability of relation between visual and ultrasonic testing results. Time-dependent degradation results of epoxy coating taken by VT were different from results taken by UT. According to aging acceleration factor, degradation pattern of epoxy coating by VT was similar not only to that by UT, but also to that by elongation change. The possibility to develop new methodology for investigation of time-dependent epoxy coating was identified.

부착력과 임피던스를 이용한 에폭시 도장의 열화에 관한 실험적 평가(II)

나환선 ( Nah Hwan-seon ),송영철 ( Song Young-chol ) 한국구조물진단유지관리공학회 2001 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.5 No.2

The purpose of this experiment is to quantitively establish aging status of epoxy coating on containment structure at nuclear power plant. On six months after accelerated aging experiment for 64 days, adhesion test was performed to evaluate an physical bonding. To compare with adhesion data, impedance data by ultrasonic test were acquired. In case of almost 50 % of adhesion force decrease, aging phenomena of epoxy coating such as pin hole, blistering was discovered. To improve reliability on quality degradation of epoxy, co-relation between two kinds of different data was analyzed. By tracing co-related these data, it is possible to figure out physical status of as-built epoxy coating. The possibility to develop new methodology of time - dependent aging status on epoxy coating was identified.

고력볼트 축력 예측 기법 개발

나환선(Nah, Hwan-Seon),최성모(Choi, Sung-Mo) 대한건축학회 2016 대한건축학회 학술발표대회 논문집 Vol.36 No.2

The clamping of torque shear high strength bolt is induced when the pin-tail is broken. However the tension forces induced shank of the bolt do not be known by now. This study focused to develop a quantitative method to identify the induced tension by analyzing the electric energy of which diverse electric torque wrenches was applied to high strength bolt at the break of pin tail. Based on this co-relation between tension and accumulated current, the regressive analysis on diverse bolt diameters was derived individually. The error rate between tension device and trial product based on effective current was below 5.0%. Based on lots of test result, it showed that this inspection method was considerably reliable. The trial product that embedded in the developed algorithms dependent to bolt diameter, electric torque wrenches was manufactured to be applied to onsite condition.

한국전력공사 전력연구원 배전연구소

나환선(Hwan Seon Nah) 한국강구조학회 2014 韓國鋼構造學會誌 Vol.26 No.4