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부재 내력과 접합부 내력을 고려한 송전강관철탑의 극한하중 도출에 관한 연구
Current design practice of electric transmission tower is based on allowable stress design. Design strength of compression member of the electric transmission tower is determined by buckling strength of member itself without considering the joint strength. There is a possibility of joint failure prior to buckling of member. Therefore, in this study, joint strength is calculated for various member force, and shape of joint and database of strength was established. These data was compared with the member strength obtained from previous research based on equivalent nonlinear analysis technique. Finally, practical evaluation and design method to distinguish failure mode in member of electric transmission tower is proposed.
全範駿 江陵原洲大學校 大學院 2009 국내박사
The curling shapes of jointed concrete pavement are varied due to temperature and humidity differences throughout the depth of the slab. Since the curling may cause a change in the elevation of the slab, pavement roughness can vary due to curling. In a single day, changes in the curling shape may cause variations in the roughness index. Since the curvature of the slab due to curling and warping is significant for the structural and functional performance of jointed concrete pavement, a simple technique to measure the curling shape of a slab needs to be developed. This study investigates a method that evaluates the realistic roughness of the road while eliminating the curling effect. The direct measurement of curling is difficult and expensive. Therefore, in this study, a method that estimates the curling displacement from the profile data is suggested. Profile data are presented in a random wave form; however, the profile data can be considered as a combination of a number of harmonic waves. Among the combinations of the various wave profiles, the data corresponding to a uniform slab length existed in a particular wavelength range. Thus, the curling of the slab at any given time can be measured if the wave, which has a particular wavelength that corresponds to the slab length (the joint spacing) of the jointed concrete pavement, can be extracted from the profile data. Technically, the Power Spectrum Density Analysis, Fast Fourier Transform, and Inverse Fast Fourier Transform techniques were applied to the profile data in order to extract the curling of the slab. A Slab Curling Extraction Method (S.C.E.M) for jointed concrete pavement was developed via the use of the techniques and procedures suggested in this study. In addition, a user-friendly program was developed to calculate curling and to reevaluate the pavement roughness index when the curling has been eliminated. The developed program (T-IRI) was used to analyze the curling and the modified roughness of a Korean Test Road on the Jung-Bu Inland expressway and on a Hanam-Tongyoung Section of the Jung-Bu expressway. The curling displacement and the IRI interrelation tended to influence the IRI as the curling displacement increased. Furthermore, the modified IRI shows that the misleading IRI measurements of the daily curling were reduced by eliminating curling from the IRI evaluation. In addition, it was analyzed for various effect factors (slab length and subbase-type) by the 3-D finite element method (3D-FEM). The curling displacement decreased in the 8m joint spacing. In this study, 3D-FEM was used to compare and estimate the type of subbase. A larger curling displacement occurred in the crushed aggregate subbases compared to the lean concrete subbase. Based on the results obtained in the present study, the methods presented herein are interpreted as a little more reliable than slab curling when studying curling and its impact on the roughness index.