구조물 환기성능 평가에서 기존 사용된 환기 지표 (ACH: Air Change per Hour)는 유체가 거동하는 구조물 내 유량의 흡·배기량과 전체 볼륨에 의해 결정된다. 이는 구조물 내 유체 유동 중 국부적으로 정체된 흐름을 평가하는 지표로 사용하기 부적합하다. 본 논문에서는 구조물에서 국부적으로 정체된 흐름을 정량적으로 나타내기 위해 역류량을 이용하여 새로운 지표 (κ: 역류량 지수)를 제안 하고, 구조형상 변수에 의해 국부적으로 정체된 유체 흐름을 평가한다. 유체 흐름 영향인자로 구조형상 변수는 공극비 (ρ), 공극 개수 (N)로 선정한다. 전산 유체 역학 (CFD)에 의한 해석 결과, 구조형상 변수에 의한 자연 환기 성능은 유사하지만, 공극의 유무에 의한 국부 정체 기류의 크기에는 차이가 발생함이 나타난다. 또한, 역류량 지수는 구조형상 변수 각각 감소함에 따라 값이 증가하는 경향이 나타난다. 본 결과를 바탕으로 회귀분석을 통해 공극비과 공극 개수 변수에 의한 역류량과 역류량 지수의 근사값이 제시된다.

The focus of this study is to investigate the ASR of concrete incorporating pre-treated soda-lime glass as aggregates. The glass aggregates were pre-treated with three different techniques, i.e. Ca(OH)2, NaOH and the mixed solution. The results indicate that all the pre-treatment techniques showed a decrease effect on ASR and such an effect increase with treatment time, the mixed solution showed the best effect. The pre-treated glass aggregate at the mixed solution at 80℃ for 7 days providing a 45% reduction in the expansion caused by ASR, and it can be considered innocuous based on ASTM C1260.

본 연구는 포졸란 재료인 LCD 유리분말과 소다석회 유리분말을 혼입하였을 경우 시멘트 복합체의 내구성에 미치는 영향을 비교, 분석하기 위함이다. 연구결과에 의하면, LCD 유리분말은 소다석회 유리분말 및 플라이애시보다 알칼리- 실리카 반응 (ASR) 및 염소이온 침투 저감에 효과적인 것으로 확인되었다.

This research provides optimization techniques for concrete mixture design for chloride penetration performance and cost. For optimization, objective functions are constructed with variables representing factors used in concrete mixture design process. Multi Objective Harmony Search Algorithm (MOHSA) is used for optimization and the result gives relationship between concrete’s chloride ion diffusivity and cost.

This research provides techniques for the implementation of an integrity evaluation system developed for wind turbine structures to jack-up barge. The strain values obtained from the upper tip of the footing are to be converted into values at a single point in order to represent the structural behavior. These obtained values are evaluated simultaneously through P-M curve, generated by FEM results. Evaluating loads with P-M curve, structural stability of barge could then be monitored.

A numerical model which can simulate the entire process of corrosion-induced concrete damage is developed. In this model, we can find the change of carrying capacity of reinforced concrete structures according to the exposure time directly.

Due to expansion of service environments for the Jack-up barge, the design of the footing has been improved. In this paper, the structure analysis of the modified spudcan based on DNV-OS-C201 examples was assessed.

Impact Severity is important parameter to design concrete barrier in South Korea. However, maximum load and load-time history graph showed different depending on parameters under vehicle impact loading. Therefore, in this study, analysis according was conducted to various impact conditions such as vehicle mass and impact velocity under same impact severity. Obtained results from load-time history graph showed key parameter is velocity compared to vehicle mass.

To calculate back the soil pressure acting on culverts, a technique for estimating the actual soil pressure has been established. The comparison between the design soil pressure and the real soil pressure is included.

The combined effect of carbonation and chloride ingress in concrete is studied in this paper. A coupled simulation of the transports of carbon dioxide, chloride ions, heat and moisture is carried out. Several sets of experimental data were compared with the prediction by the numerical model developed in this paper, for its verification.