The purpose of this study is to investigate the characteristics of asbestos containing materials in public facilities in Korea. We investigated 201 public facilities between January and December in 2009. PACM were collected according to EPA AHERA rules, and analyzed using the US EPA method 600/R/116. The air samples from public facilities were analyzed by PCM. For the survey on ACM risk assessment, we used both the ASTM rules and Korea ACM risk assessment(developed by the Korea ministry of employment and labor). Public facilities showed that ceiling textiles contained chrysolite/amosite(2 and 25%) and cement flat boards contained chrysolite(5 and 26%). Also, gaskets contained chrysolite(3 and 95%) and Floor tile & carpet contained chrysolite(less than 1 and 6%). PCM analysis was performed on all air samples, and it was found that the concentration of fiber did not exceed the Korean guideline(0.01f/cc). In this study, it was found that according to the ASTM rule of asbestos material, 70 materials were “Abatement” grade and 344 materials were “Q&M” grade when assessed by ASTM B-line. Furthermore, based on the adjusted Korea ACM risk assessment 22 materials rated as were “Fair” and 390 materials were “Good”.

본 연구에서는 1차항 판이론에 기반한 적층된 ACM 경사판의 기하학적 비선형 동적해석을 수행하였다. 비선형 동 적해를 구하기 위하여 Newmark 방법과 Newton-Raphson 반복법을 혼용하여 적용하였다. 본 연구에서 개발한 유한요 소 해석프로그램을 사용하여 경사각도와 적층 배열의 변화가 판의 기하학적 비선형 거동에 미치는 영향을 상세 분 석하였다. 몇 가지 수치해석 결과는 기존 연구자로부터 얻어진 결과와 잘 일치하는 것으로 나타났다. 본 연구의 새 로운 결과는 경사 적층 구조의 경사각도와 적층 배열과의 중요한 상호관계를 보여준다. 몇 가지 수치예제는 ACM 경사 적층판을 설계하는데 필요한 가이드라인을 제시하였다.

In this paper, the analysis of impact damage behavior of a reinforced concrete structure that undergoes both a shock impulsive loading and an impact loading due to the air blast induced from an explosion is performed. Firstly, a pair of multiple loadings are selected from the scenario that an imaginary explosion accident is assumed. The RC structures strengthened with advanced composite materials (ACM) are considered as a scheme for retrofitting RC wall structures subjected to multiple explosive loadings and then the evaluation of the resistant performance against them is presented in comparison with the result of the evaluation of a RC structure without a retrofit. Also, in order to derive the result of the analysis similar to that of real explosion experiments, which require the vast investment and expense for facilities, the constitutive equation and the equation of state (EOS) which can describe the real impact and shock phenomena accurately are included with them. In addition, the numerical simulations of two concrete structures are achieved using AUTODYN-3D, an explicit analysis program, in order to prove the retrofit performance of a ACM-strengthened RC wall structure.

본 연구는 차량 이동하중을 받는 손상된 콘크리트 슬래브교량의 강성저하를 규명하고, 복합신소재를 사용하여 보강 후 성능평가를 수행한다. 특히 마이크로 유전알고리즘에 의한 역해석에 기반하여 보강 전·후 각 요소에서의 강성변 화를 수정된 2차변수 Gaussian 분포함수를 사용하여 정식화하였다. 본 연구에서 제안한 방법은 기존의 요소기반 접 근 방식에 비하여 수치해석적인 관점에서 효율성을 갖는다. 개발한 알고리즘은 3차원 솔리드 요소를 사용하여 모델 링한 교량의 동적 거동 시뮬레이션으로부터 계측한 데이터를 사전정보로 사용하여 검증하였다. 몇 가지 수치예제는 본 연구에서 개발한 방법이 실제교량과 수치모델간의 차이로 인한 오차 및 노이즈 등으로 인한 동적 계측치 오류 등이 고려되었음에도 강성분포 추정 및 성능 평가를 효율적으로 수행함을 보여준다.

This study was performed to investigate the characteristics of asbestos distribution in 6 public and 6 school buildings from August to September in 2006. The bulk samples were analysed by PLM(polarized light microscope). Also the airborne samples were analysed PCM(phase contrast microscope) and confirmed by SEM-EDX(scanning electron microscope-energy dispersive using X-ray analysis) method. The 6 public buildings included the ACM(asbestos containing material) ranged 2-7 % of chrysotile in 70 % of samples from ceiling, floor tile, and wall board and has 20 % tremolite in 2 ceiling plaster. The 6 school buildings were identified 1.5 % tremolite in one sample and showed the similar asbestos distribution with the public building. The airborne concentrations of fiber materials were ranged with 0.000-0.017 f/cc in public places and 0.000-0.012 f/cc in school building by PCM. However, the asbestos fibers could not be found by SEM-EDX. In the result of physical assessment of ACM in each buildings, it is considered that there is no chance of a hazardous situation because the ACM is not friable. Its suggested that the asbestos control plan should be established to prevent asbestos exposure to occupants from damaged ACM by repairing and custodial work.