• 한국도로학회논문집
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• 제12권3호
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• pp.139-146
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• 2010

본 연구는 포스트텐션 콘크리트 포장(PTCP: Post-Tensioned Concrete Pavement)에 고속축중계(WIM: Weigh-in-Motion)를 설치한 포장 시스템의 거동을 분석하기 위하여 수행되었다. PTCP는 일차로 폭으로 기존의 아스팔트 포장을 절삭하여 제거한 후에 시공되었다. PTCP는 슬래브의 연장이 길기 때문에 긴장을 통해 프리스트레스를 적절히 작용시키기 위해서는 슬래브와 하부층과의 마찰이 적어야 하며 이러한 영향을 시험시공을 통해 우선적으로 분석하였으며, 환경하중에 따른 슬래브의 종방향 거동도 분석하였다. 시험시공을 통해 얻은 결과를 바탕으로 공용중인 도로에 WIM 센서를 설치한 PTCP를 시공하였으며 이러한 포장체가 환경하중을 받을 때의 컬링 거동을 측정하여 특성을 분석하였다. 연구결과 PTCP 슬래브 상부의 일부를 절삭하여 WIM 센서를 설치하더라도 PTCP의 거동은 이에 영향을 받지 않는 것을 알 수 있었으며, WIM 센서의 정밀 측정에 부합되는 PTCP 시스템을 시공할 수 있는 기반을 마련하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1503-1510
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• 2011

The dropper length calculation method about the normal same encumbrance spans is well known independent to whether the pre-sag is given or not. But, the dropper length calculation method for the elevating span which consists in the end area of a tensioning section and normally consists with overlaps is not well known. In this study, firstly, we investigate the dropper length calculation method about the elevating span whether the insulator is contained in or not, we also recognize the effect of dropper length due to the change of the take-off point. Secondly, we very this calculation method with a catenary sample data and check again with Gyeongbu HSL design data.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.619-624
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• 2002

A prestressed/precast concrete system was used to build the new Asian Olympic Stadium Project in Pusan, Korea. The stadium(mainly intended for cycle racing) is designed for the 2002 Asian Olympic Games and has a seating capacity of 20,000 spectators plus a few private suites. More than 1300 prestressed/precast components were used and they include single columns, primary beams, cantilever beams, double riser stands, and double tees. Especially, a total of 24 cantilever beams is used on the fourth story for the stands and double tees. These 8m long beams are post-tensioned to prevent cracking, to increase their durability and to serve serviceability by vibration. A cantilever section with cast-in-place topping is 800mm wide and 1500mm deep. Cantilever beams are connected to the column with the corbel by cast-in place concrete. Bonded post-tensioning tendons were assembled at the job site. Dead-end anchorages were installed in the end of cantilever beams and live-end anchorage is the opposite of them. This article presents the geometric layouts, design features and so on.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1994년도 가을 학술발표회 논문집
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• pp.87-94
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• 1994

During the construction of externally prestressed 7-span continuous segmental bridge, cracks beyond permissible limit were found at anchor zone of expansion joint segment. To eliminate this problem, tension side of diaphragm was prestressed by post-tensioning bars in vertical and horizontal direction. To investigate this remedy is acceptable, stresses of reinforcing bars and concrete surface were measured for the real structure in the field. The measurement was performed through each step of prestressing sequence during construction. Also to investigage stresses induced by live load, static load test was performed and the results was analyzed. In this paper it will be presented the procedure and results for this experimental study along with comparison with analytical study.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.135-140
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• 2001

A post-tensioned reinforced concrete slab bridge is analyzed by specially orthotropic laminate theory. Symmetrically reinforced slab with tension and compression steel is considered for convenience of analysis. Each longitudinal and transverse steel layer is regarded as a lamina, and material constants of each lamina is calculated by the use of the rule of mixture. This bridge is under uniformly distributed vertical loads, and axial loads and end moments due to post-tensioning. In this paper, finite difference method is used for numerical analysis of this bridge. Theory and analysis method of specially orthotropic laminate plates used in this paper can be used for design of new bridges, and maintenance and repair of old bridges.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.487-492
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• 2002

The interior portion of Gerber's beam are constructed with post-tensioned segmental composite beams in this study. A precast concrete member which is larger than the limits of domestic transportation regulation in weight, length, and volume is divided into three parts, transported separately, and erected with a composite member by post-tensioning in site. Static flexural loading tests are performed on Gerber's type frames which are consisted with 2.5m overhangs and 5m interior beams composited from three pieces. The connection of overhang to interior composite beam and beam to beam, and flexural performance of interior portion of Gerber's beam are examined thoroughly. All of the tests are ended with a compression failure of the interior composite beams over the design strength of homogeneous beams. The brittle connection failures or tensile failures with the failure of lower strand was not observed in any test frames.

• 대한정형외과스포츠의학회지
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• 제2권1호
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• pp.15-19
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• 2003

Although the number of anterior cruciate ligament reconstruction is increasing, complications after primary ACL reconstruction are more difficult to determine. Intraoperative and postoperative complications can lead to ultimate failure of a primary reconstructive procedure. Therefore, surgical success in ACL reconstruction requires detailed knowledge and technical advancements about ACL reconstruction. Preoperatively surgeon must pay attention to selection of grafts and methods of fixation, and intraoperatively, attention to the harvest of graft, passage of graft, intraarticuar placement of the graft, notchplasty, proper tensioning of the graft, and others. Postoperative complications must be detected early, including infection, abnormal healing responses, arthrofibrosis, graft rejection, and reflex sympathetic dystrophy. Careful patient selection, appropriate surgical timing, careful surgical technique, and supervised preoperative and postoperative rehabilitation can minimize postoperative complications.

• Computers and Concrete
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• 제10권2호
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• pp.121-133
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• 2012

Structures suffer from damages in their lifetime due to time-dependant effects, such as fatigue, creep and shrinkage, which can be expressed by concrete strains. These processes could be seen in the context of strain estimation of pre-stressed structures in two phases by using numerical methods. Their aim is checking and validating existing code procedures in determination of deformations of pre-tensioned girders by solving a system of nonlinear equations with strains as unknown parameters. This paper presents an approach based on the Newton-Raphson method for obtaining the stresses and strains in middle span section of pre-stressed girders according the equilibrium state.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.399-404
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• 1999

An improved finite element modeling technique is proposed for the assessment of load carrying capacity partilly prestressed concrete beam bridges. Based on the finite element method of analysis, shell and frame elements are utilized to model the slab and beams of the superstructure, respectively. In the modeling of superstructure, the emphasis is placed on the use of rigid link between the middle surface of slab and mid-plane of beam. This paper also includes the comparision of three different equations that used in the calculation of effective moment of inertia for the partially prestressed concrete beams. Numerical analysis is performed for the unstrengthened and strengthened bridges. The obtained results are compared with those of load test for a prototype bridge. Agreement with the numerical solutions by using the proposed method and load test results is generally excellent.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.226-229
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• 2006

Strengthening with externally post-tensioned CFRP strips is more effective in increasing load carrying capacity of existing structures as well as reducing crack width and deflection. This study developed concrete embedded anchorages system for externally post-tensioned CFRP strips, and carried out experimental study to verify anchoring performance quantitatively. Through experimental results, anchoring strength of concrete embedded anchorage were quantified into shear strength of anchor bolt, bearing strength of concrete at the front of anchor plate and bond strength between anchor plate and concrete surface. In addition, overall anchoring performances according to combination of each unit force are examined in this study.