노천 발파패턴에 따른 발파상수의 정량적 평가

강성후,박선준 東新大學校 工業技術硏究所 2002 工業技術硏究 Vol.8 No.-

The actual ground vibrations due to prism cut and trench cut blasting at power plant field have been measured, and the data were analyzed using reliability index(β) to the blast constants and attenuation coefficients. In this study, blast vibrations were suggested with wave component parts of ground vibration to the blast patterns, and were suggested with the division of ultimate limit state(,8 =0), serviceability limit state(β=1.28) and safety state(β =3) respectively. The reliability index 0 means 50% data line obtained by the least squares best-fit line. The reliability index 1.28 and 3 represent bounds below 90%, and 99.9% of the data, respectively. The vibration constants K(particle velocity) for prism cut were evaluated to 333, 619, 1419, respectively and the attenuation coefficients of vibrations was -1.94. From this study, inference and analysis methods of vibration equations using reliability theory were established.

동적하중을 받는 고강도 콘크리트 보의 파괴거동

강성후,박선준 대한토목학회 1995 대한토목학회 학술발표회 논문집 Vol.1995 No.1

3경간 연속 중로식 강아치교의 내풍안정성을 고려한 라이즈 비 특성

강성후,박선준,최명기 東新大學校 工業技術硏究所 2004 工業技術硏究 Vol.10 No.-

The most important element is a rise ratio when regarding beauty and economics of arch bridges. Only the effect of dead load has been considered to decide the rise ratio. In this study, when going over the rise ratio of arch bridges, examined the problems, that the determination of the rise ratio by the dead load has, by adding the factor of a determination of optimum rise ratio, which is not only the effect of the dead load that has been currently considered but also the problem with respect to wind resistant dynamic stability that is now taken seriously. Synthetically, when deciding rise ratio that is investigated in basic step of design, it is not necessary to consider the evaluation wind resistant dynamic stability. Therefore the result of this research can be summarized as followes ; If it is identify oneself with rise ratio that the divided ratio due to the tie girder of the 3 continuous spans half-through steel arch bridges cannot cause a big effect in stability the wind resistant dynamic stability. If it is identify oneself with the relative stiffness ratio and girder depth ratio of the 3 continuous spans half-through steel arch bridges that the rise ratio proposes that it uses 0.10~0.30, divided ratio due to tie girder proposes that it uses 1.0~2.5 because of the wind resistant dynamic stability and the stress of the hanger. The rise ratio proposes that it uses 0.16~0.18 is given by the Japanese bridge construction association to obtained in investigation equation between an arch span length and the rise, using 0.1~0.2 at the basic design phase and the divided ratio which using 1.5 due to tie girder generally has been employed to main results and very well agrees with a research accomplishment results.

Mix Design Nomogram을 이용한 콘크리트 파괴에너지 예측

강성후,박선준,정철오 한국구조물진단유지관리공학회 2006 한국구조물진단유지관리공학회 논문집 Vol.10 No.3

본 연구에서는 레미콘 제품에 Mix Design Nomogram을 적용하여 배합변수에 따른 파괴에너지 예측뿐만 아니라 파괴에너지에 따른 배합변수 예측을 가능하도록 하는데 그 목적이 있다. Mix Design Nomogram 작성을 위한 실험은 레미콘 생산회사의 실제 시방배합표를 사용하였으며, RILEM 50-FMC 위원회에서 제안한 3점 휨 실험을 실시하였다. 그 결과, 레미콘 제품에 파괴에너지가 예측 가능한 Mix Design Nomogram의 적용 가능성을 확인하였으며, 이를 이용한 프로그램 개발로 레미콘 배합설계 자동화를 위한 가능성을 확인하였다. The purpose of this study is to predict the fracture energy in accordance with the combination variables by applying the mix design nomogram in ready mixed concrete products. In terms of the experiment for drawing up Mix Design Nomogram, the beam is manufactured based on the mixture table described in the specifications of ready mixed concrete manufacturing company and a three-point bending test suggested in RILEM 50-FMC Committee is performed. As a result, this study makes sure the possibility to apply the mix design nomogram that is possible to predict the fracture energy in ready mixed concrete products and enables one to achieve the automation of the design of mixture for the production of ready mixed concrete products with the development of program using it.

PSC I형 단순 철도교량의 동적사용성 평가

강성후,최태근,박선준,김성일,Kang,Sung-Hoo,Choi,Tae-Geun,Park,Sun-Joon,Kim,Sung-Il 한국방재학회 2009 한국방재학회논문집 Vol.9 No.1

본 연구에서는 기존의 25 m 지간을 갖는 PSC I형 단순 철도교에 대해 고속 및 일반 열차하중으로 인한 동적거동을 분석하여 철도교량의 동적사용성을 평가하였다. 고유진동수는 8Hz 대역으로 평가되어 철도교량의 적정 고유진동수 범위 내에 들어있으며, 공진발생 가능성은 없는 것으로 나타났다. 가속도 응답은 무궁화호 열차 주행 시 제한 값 0.35 g를 초과하는 0.43 g가계측되었다. 또한 단부꺽임각은 고속철도의 설계기준을 만족하지 못하였으며 충격계수와 처짐은 모두 설계기준을 만족하였다. 결과적으로 25 m 지간을 갖는 PSC I형 단순 철도교의 경우 다양한 열차하중에 대하여 동적사용성을 부분적으로 확보하고 있는 것으로 나타났으나 진동가속도 응답을 감소시키기 위한 대책이 필요할 것으로 판단된다. In this study, dynamic serviceability of PSC, PreStressed Concrete, simple railway bridge with 25m span was estimated. All of the high speed and general train loads were considered at estimation. Natural frequency is estimated about 8Hz and includes within optimum natural frequency extent of the railway bridge. Also, the bridge was detected that resonance occurrence possibility does not exist. When travel the Moogunghwa train, acceleration response was measured to 0.43g that exceed limitation value 0.35g. Also, rotation angle of girders end did not satisfy design standard of railway bridge for high speed train, but impact coefficient and deflection satisfied design standard. As a result, that railway bridge was detected that is securing dynamic safety and serviceability partially, but methods to decrease vibration acceleration response are required.

3경간 중로식 아치교량의 풍하중에 대한 동적안전성

강성후,박선준,정철호 東新大學校 工業技術硏究所 2003 工業技術硏究 Vol.9 No.-

Recently, bridges have been momentous as not only regarding function but also concerning aesthetics. However, when beauty is considered in the design, it is also essential that stability and economics be considered. Moreover, when considering stability, an arch bridge is one of the most stable structures. The most important element is a rise ratio when regarding beauty and economics of arch bridges. Only the effect of dead load has been considered to decide the rise ratio. Therefore, in this study, when going over the rise ratio of 3-Span half through type arch bridges, I examined the problems, that the determination of the rise ratio by the dead load has, by adding the factor of a determination of optimum rise ratio, which is not only the effect of the dead load that has been currently considered but also the problem with respect to wind-resistant dynamic stability that is now taken seriously.

국부가열에 따른 강재의 온도 및 강도 변화에 관한 실험적 연구

강성후,김민중,김성환,박선준,Kang. Sunghoo,Kim. Minjung,Kim. Sunghwan,Park. Sunjoon 한국방재학회 2013 한국방재학회논문집 Vol.13 No.6

본 연구에서는 전기적인 방법에 의해 강재가 국부 가열될 때 강재에 발생되는 열유지율을 정량적으로 평가하고, 국부적으로 가열된 강재의 강도특성 변화를 실험적 방법으로 규명하였다. 이를 위하여 두께 6 mm, 12 mm, 18 mm 강판 시험편을 사용하여 실험하였다. 제한적인 본 실험의 조건에서 강판의 온도는 최대 <TEX>$125.2^{\circ}C$</TEX>까지 상승하였으며 이곳으로부터 이격거리가 각각 200 mm, 400 mm인 위치에서 열유지율은 평균 22.9%와 18.4%로 각각 나타났다. 국부 가열된 강재의 인장강도 시험 결과, 강재 시험편의 두께에 상관없이 모두 SS400강재에 요구되는 인장강도 400 MPa과 항복강도 240 MPa을 모두 충족하였다. 연신율의 경우에는 모든 시험편에서 20~30%의 값을 보여 정상 범위에 있는 것으로 나타났다. 이러한 제한된 조건의 실내 실험 결과들로부터 강재가 <TEX>$20{\sim}120^{\circ}C$</TEX>의 온도 수준으로 국부 가열되는 경우 강재의 성능은 저하되지 않는 것으로 나타났다. In this study, the retention rate of heat that is generated when steel is locally heated by electrical means was quantitatively evaluated and changes in strength properties of the steel were investigated by experimentation. To do so, the experiment was conducted on specimens with thicknesses of 6 mm, 12 mm and 18 mm. With the limited conditions of this experiment, the steel plate was heated to at most <TEX>$125.2^{\circ}C$</TEX> and the average heat retention rates at 200 mm and 400 mm away from this measurement point were 22.9% and 18.4%, respectively. For the results of the tensile strength test of the locally heated steel, a tensile strength of 400 MPa and yielding strength of 240 MPa that are required from SS400 were all satisfied regardless of the thickness of the steel specimen. In the case of percent elongation, all specimens showed values of 20-30% being within the normal range. The results of the indoor experiment with such restricted conditions showed that the performance of steel is not diminished when locally heated to temperatures of <TEX>$20-120^{\circ}C$</TEX>.

콘크리트 충전 강상자형 교량의 진동사용성 평가 연구

강성후,박선준 한국방재학회 2016 한국방재학회논문집 Vol.16 No.3

The subject of this study was a two-span continuous concrete-filled steel box girder bridge. The bridge surface vibration was quantitatively measured by driving a vehicle of which total weight was 267 kN. The vibrational effect was assessed focusing on pedestrians on the basis of the experimental results. A ‘concrete-filled steel box’ is prepared by filling concrete in a separate box inside the conventional steel box. In a continuous bridge, concrete is restrictedly filled in the internal part where a negative moment is generated. A vibration acceleration response prediction equation was proposed by using the acceleration response and the scaled-weight obtained from the experiment. The proposed equation may be used to preliminarily predict the paved surface vibration response of a concrete-filled steel box girder bridge, though the applicable weight and speed of cars are partly limited. The vibration serviceability was assessed by using acceleration conversion curve of the Reiher-Meister. When the driving velocity of the vehicle used in the experiment was in the range of 10 km/h to 30 km/h, the vibration was in ‘Level E’where the pedestrians are unable to recognize vibration. When the velocity of the vehicle was in the range of 40 km/h to 60 km/h, the vibration was in ‘Levels D to E’ which are the appropriate levels where the pedestrians do not feel uncomfortable, indicating that the bridge secured appropriate vibration serviceability. 본 연구에서는 2경간 연속 콘크리트 충전 강상자형 교량을 대상으로 차량 진동이 유발시키는 교면진동의 크기를 총중량 267 kN의 차량 주행실험으로 부터 정량적으로 평가하고 이를 이용하여 보행자 중심의 진동영향을 평가하였다. ‘콘크리트 충전 강상자형’은 기존의 강상자형 내부에 별도의 상자를 만들어 콘크리트를 충전하는 형태로써 연속교에서 부모멘트가 발생하는 내측지점 부에 제한적으로 적용된다. 진동 가속도 응답 추정식은 실험으로부터 얻어진 가속도 응답과 환산중량을 사용하여 제안하였다. 제안된 식은 차량의 중량과 주행속도 등이 제한적이지만 콘크리트 충전 강상자형 교량의 교면 진동응답을 우선 추정하는데 사용이 가능하다. Reiher-Meister의 가속도 변환곡선에 준하여 진동사용성을 평가한 결과 10 km/h~30 km/h의 주행속도 일때는 보행자가 인지하지 못하는 수준인 ‘Level E’ 로 나타났고 40 km/h~60 km/h의 주행속도 일 때는 ‘Level D~E’로 나타났다. ‘Level D~E’는 보행자에게 불쾌감을 유발하지 않는 적정한 수준의 진동사용성을 확보하고 있는 상태를 의미한다.

지회소식/위원회 소식/회원동정

강성후,한상훈,권수안,이복남 대한토목학회 2015 대한토목학회지 Vol.63 No.5

동적하중(動的荷重)을 받는 콘크리트의 구열(龜裂)성장

강성후,김우,Kang, Sung Hoo,Kim, Woo 대한토목학회 1988 대한토목학회논문집 Vol.8 No.2

본(本) 연구(硏究)는 재료(材料)의 배합(配合)이 단순한 mortar를 제작 그 균열발생을 관찰, 측정하여 정적하중(靜的荷重)에 의한 균열 및 일정진폭을 갖는 동적하중(動的荷重)에 의한 균열성장영역 예측을 시도한 것이다. 사용시편은 mortar의 배합비(配合比)와 물-시멘트비(比)를 달리하여 ASTM E 561-80에서 제안한 CLWL-DCB(crack-line-loaded-double-cantilever-beam)의 제1방법인 벽개형(劈開型)모드(opening mode)에 의거 균열성장거동을 측정하였다. 본(本) 실험(實驗)에서는 X-Y recorder에 나타난 하중(荷重)(P)-균열개구변위($2V_1$), 균열개구변위($2V_1$)-균열선단개구변위($2V_2$)의 diagram을 해석하여 정적하중(靜的荷重)에 의한 균열선단의 비선형적인 미소균열을 포함하는 유효균열길이(effective crack length; $a_e$)와 균열선단의 미소균열을 제외한 물리적균열길이(physical crack length; $a_m$) 및 replica 필름으로 구한 균열길이(replica crack length; $a_t$)의 상관관계와 일정진폭을 갖는 반복하중에 의한 $a_e$, $a_m$, $a_t$를 구하여 정적하중(靜的荷重)에 의한 균열특성과 동적하중(動的荷重)에 의한 균열특성을 조사한 것이다. This study deals with the prediction of crack propagation in concrete mortar subjected to static and dynamic load. Total 54 CLWL-DCB(Crack-line-loaded-double-cantilever beam) concrete mortar specimens were tested to measure crack growth using ASTM 561-80. Main variables were sand to cement ratio and water to cement ratio. The resulting load(P)-COD(Crack Opening Displacement; $2V_1$) curves and COD-CTOD (Crack Tip Opening Displacement; $2V_2$) curves were analyzed to calculate effective crack length and physical crack length by way of ASTM 561-80 proposed. Replica crack length were also obtained directly during the test. The differences in crack propagation between under static load and under dynamic load were investigated.