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Structural test of precast polymer concrete
Ahn, Namshik,Park, Do Kyong,Lee, Jaehong,Lee, Myung Kue Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of applied polymer science Vol.114 No.3
<P>This study was performed to check the feasibility of concrete polymer manhole through a development test of high strength polymer concrete and prepare fundamental data for design to solve the problems of the existing cement concrete manhole. The lower absorption capacity (0.39%) of polymer concrete will be more advantageous in installing manhole in an area with subsurface water. Also long working-life (63 minutes) will be enough to establish manholes. Conclusively, the high strength polymer concrete that is the most important issue in development of polymer concrete manhole could be made. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009</P>
A study on transverse vibration characteristics of a sandwich plate with asymmetrical faces
Ahn, Namshik,Lee, Kangsu Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.4
Sandwich elements have high flexural rigidity and high strength per density. They also have excellent anti-vibration and anti-noise characteristics. Therefore, they are used for structures of airplanes and high speed ships that must be light, as well as strong. In this paper, the Reissner-Mindlin's plate theory is studied from a Hamilton's principle point of view. This theory is modified to include the influence of shear deformation and rotary inertia, and the equation of motion is derived using energy relationships. The theory is applied to a rectangular sandwich model which has isotropic, asymmetrical faces and an isotropic core. Investigations are conducted for five different plate thicknesses. These plates are identical to the sandwich plates currently used in various structural elements of surface effect ships (SES). The boundary conditions are set to simple supports and fixed supports. The elastic and shear moduli are obtained from the four-point bending tests on the sandwich beams.
안남식,이영학,Ahn. Namshik,Lee. Young Hak 한국방재학회 2012 한국방재학회논문집 Vol.12 No.2
합성부재의 설계에 있어서 콘크리와 강재의 일체화된 거동은 매우 중요하게 고려되며, 효과적인 합성작용을 위해 전단 스터드가 가장 보편적으로 사용되고 있다. 본 연구의 목적은 고강도 콘크리트에서의 전단 스터드 내력 산정식을 제안하고, 이를 기존의 규준식 및 제안식과 비교 분석하여 그 유효성을 평가하는 것이다. 전단 스터드의 지름, 전단 스터드의 지름 대 높이의 비(H/d ratio)를 변수로 한 강관매입형 합성부재의 실험결과를 토대로 회귀분석을 수행하여 전단 스터드 내력 산정식을 제안하였다. 본 연구에서 제안한 내력 산정식을 기존 연구식들과 비교한 결과, KBC2009와 정회용등의 제안식이 실험값에 대하여 각각 48.78%, 28.03%의 큰 오차를 보이며 고강도 콘크리트의 전단 스터드 내력을 정확하게 평가하지 못하는 것으로 나타났으나, 본 연구의 제안식은 실험값과 약 3.69% 정도의 근소한 오차를 보이며 고강도 콘크리트가 사용된 합성부재의 전단 스터드 내력을 비교적 정확하게 평가하는 것으로 나타났다. For design of composite concrete members, the behavior between two materials; concrete and steel is considered significantly. And shear studs are generally used for effective composite action. The purpose of this paper are to propose an equation of strength of shear stud embedded in high strength concrete, and to evaluate the validity by comparing with the current design codes and existing proposed equations. The equation was proposed by regression analysis based on the test results of steel pipe encased composite members manufactured by considering diameter of shear stud and ratio of diameter to height of shear stud as variables. The comparisons of the test results with the design codes and existing proposed equations showed that KBC2009 and the equation of Cheong et al. have big error; 48.78% and 28.03%. And the equation proposed in this paper indicate relatively smaller error of 3.69%. It indicated that the proposed equation has higher accuracy for calculating the strength of shear stud embedded in high strength concrete.