• 한국공간구조학회논문집
• /
• 제6권2호
• /
• pp.69-76
• /
• 2006

케이블 돔은 초기에 불안정한 상태에서 각각의 케이블에 장력을 도입하면서 점차적으로 안정화되는 구조이다. 이러한 과정은 케이블에 압축력이 발생하게 되며, 일반적인 구조해석으로는 그 해를 찾을 수 없으므로 이 논문에서는 동적이완법을 사용한다. 또한, 안정화 이행과정해석을 실제적인 문제에 적용하는 방법으로 서울올림픽 체조경기장 케이블 돔 지붕에 적용함으로써 해석결과와 실측결과를 비교하고 안정화 이행과정해석의 적절함을 검증한다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
• /
• pp.769-774
• /
• 2000

The first thing in developing precast post-tensioned concrete frame system verify the shear resistance capacity of the beam-column connection at which the transfer of member forces become discontinuous. Complying with the necessity of such experimental research, shear tests have been performed for six test specimens which were cast and cured at Dong-Ah Concrete Manufacturing Company and post-tensioning at Concrete Laboratory of Inha University. Shear key and magnitude of post-tensioned force are taken test variables. From the test results, it has been observed that the shear resistance of the specimens attained to higher values than those of theoritical calculations based on the shear friction with shear friction coefficient being 0.6.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
• /
• pp.347-352
• /
• 1998

The purpose of this paper is to present and establish a procedure to predict the prestress forces during the service life of the structure. The statistical approach of this procedure is using the in-situ measurement data of the post-tensioning system to develop a nonlinear regression analysis. The method of least squares is used to fit a certain function a set of data. Use of a nonlinear model is achieved by its logarithmic transformation and sunsequent use of linear-regression theory. The regression analysis result can be used to check the prestress force during the service life so that the remaining prestress force is equal to or exceeds the design requirement. Results from the measurement data of PSC box girder bridge structure were used to demonstrate the procedures.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
• /
• pp.17-18
• /
• 2010

이 연구는 포스트텐션 콘크리트 포장(PTCP) 공법의 설계지침을 개발하기 위하여 수행되었다. 구조해석 및 실험을 통해 PTCP의 거동을 분석하였으며 이를 바탕으로 슬래브 크기, 설계 환경 및 차륜 하중, 종방향 및 횡방향 긴장과 긴장방식 결정을 통해 최적의 PTCP 설계지침을 개발하였다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.25.4-25
• /
• 2001

In this paper, a five degree-of-freedom haptic device is proposed. The proposed haptic device has a pen which is suspended by tensioned six strings. Human operator handles the pen. Six DC motors are used as actuators to generate tensions in six strings to make resultant force feedback at the pen to the human operator Six encoders are used for calculating the movement of the pen. A digital controller is used for generate control signals for the suitable tension in the six strings. A current amplifiers is used for amplifying the control signals. Cable-suspended system has advantages of structure simplicity (only with several strings driven by motors without using other tensioning mechanisms), low inertia, and high force-to-weight ratio. Pen-based system has advantages of compactness and ...

• 한국공간구조학회논문집
• /
• 제17권4호
• /
• pp.69-76
• /
• 2017

For evaluating equations of bursting force in different codes, comparative study of the formulas was conducted. Because the equations does not consider variables such as shape of anchorages, angle of tendons, and eccentricity, a relation between the bursting forces and the variables has to be analyzed. In this paper, therefore, a comparative analysis of bursting forces computed by equations in the codes and finite element analysis was performed. As a result, it could be figured out that bursting force equations in the local zone were determined by coefficient k.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
• /
• pp.639-644
• /
• 2000

Prestressing steels are susceptible to corrosion, which is considered the major reason in the deterioration of prestressed concrete structures. To solve this problem, many research have been made to utilize new type of tendons. FRP tendons have many advantages compared to steel tendons. However, FRP tendons have some disadvantages, such as no plastic behavior. This study focused on the flexural behavior of prestresssed concrete beams which is fabricated by post-tensioning method with CFRP (Carbon Fiber Reinforced Plastic) tendons. Th results drawn from the study, prestressed concrete beams with CFRP tendons have higher flexural cracking load, flexural yielding load, and flexural fracture load. While displacement at the fracture stage is lower compared to prestressed concrete beams with steel tendon. Excessive steel reinforcement lead lower ductility index. So, appropriate reinforcement guideline is needed. Further more, prestressed concrete beams with CFRP tendons can have sufficient ductility index when ruptured by crushing of concrete or used unbonded tendon. Therefore, the best design method for prestressed concrete beams with CFRP tendons is over-reinforcement, and use of unbonded tendon.

• 콘크리트학회논문집
• /
• 제12권4호
• /
• pp.121-130
• /
• 2000

Current engineering practice in determining sectional dimensions of prestressed concrete (PSC) girders for bridges is primarily based on the code-specified allowable concrete stresses at different loading stages. It is customary that tendons and sectional dimensions are calibrated and tendon forces are applied at once at the initial stage to keep the subsequent stresses occurring at different loading stages within the allowable stresses. This traditional tensioning method, however, usually results in a too conservative sectional depth in view of ultimate capacity of a girder. A new design method which can realize the reduction of sectional depth of PSC girders is theoretically suggested in this study. Tendons are tensioned twice at different loading stages: the initial stage and the stage after fresh slab concrete is cast. It can be shown that according to this technique, sectional depth can be significantly reduced and larger span can be realized compared to traditional ones. Parametric studies are performed with due considerations given to its practical applications.

• 콘크리트학회논문집
• /
• 제12권6호
• /
• pp.43-50
• /
• 2000

In this paper, a new splicing method was applied to design the girder section of bridges with the span length of 25m, 30m, 35m, 40m and 45m. A U-type precast prestressed section was also determined for each bridge. Additionally, the sectional area, beam depth and Guyon's efficiency factor of the spliced U-type sections in each span were analyzed in comparison with the present I-type PSC bridges. As a result, in spite of an increase of 31%∼50% in the sectional areas compared with the I-type precast girders, the spliced U-type the beam depth of the spliced U-type girder was designed as 2,050 mm compared with the I-type precast girder of 2,600mm in a 40m span bridge. The sectional efficiency factors of the spliced U-type sections were analyzed as 0.76∼0.99. It shows that the spliced U-type sections ar of a superior structural efficiency in contrast to the average sectional efficiency factor of 0.66 value in the I-type girders.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 1999년도 춘계학술대회 논문집
• /
• pp.434-441
• /
• 1999

The newly proposed Precast Segmental Mettled (PSM), which makes use of precast elements for election, is relatively new, efficient and fast mettled for the construction of prestressed box girder bridges. A precast segment of 25m long pretensioned in the fabrication yard is transported by a special trailer and a launching truss to its final position. The segments are then connected in the site by post-tensioning to make a continuous prestressed concrete box girder bridges. The purpose of this parer is to analyze and evaluate the design of precast prestressed concrete box girder bridges. The detailed analyses including time-dependent behavior of PSM bridges are conducted. The major results and findings, which have been obtained from finite element analysis of PSM bridge, are discussed in this paper and these results will be a good base for the design and analysis of a new precast bridges.