In this study, the static load test and the load transfer test were carried out to evaluate the structural performance of the circular anchorage proposed by the previous study. Specimens were fabricated according to KCI-PS101 and ETAG 013. As a result of the static load test, it was verified that the displacement of the wedge and the strand was kept constant when the tensile force of 80% of the nominal strength of the strand was applied. In the load transfer test, it was confirmed that all the specimens satisfied the stabilization formula of KCI-PS101 and ETAG 013. Post-tensioned one-way slab with circular anchorage were fabricated to evaluate the flexural behavior. All specimens exhibited the same flexural behavior and maximum load. However, the specimen with circular anchorage were advantageous than the rectangular anchorage one in terms of crack control of the anchorage zone.

In the post-tensioned concrete member, additional reinforcement is required to prevent failure in the anchorage zone. In this study, the details of reinforcement suitable for the anchorage zone of the post-tensioned concrete member using circular anchorage was proposed based on the experimental results. The tests were conducted with the compressive strength of concrete and reinforcement types as variables. The experimental results indicated that the additional reinforcement for the anchorage zone is required when the compressive strength of concrete is less than 17.5 MPa. U-shaped reinforcement shows most effective performance in terms of maximum strength and cracks patterns.

본 논문에서는 상용프로그램을 이용한 유한요소해석을 통하여 포스트텐션 정착구역에서 보다 효율적인 응력분산이 가능 한 비부착식 단일 강연선용 포스트텐션 정착구 형상을 개발하는 것을 목표로 하였다. 이를 위하여 정착구 형상을 구성하는 각 부분의 변수해석을 수행하였다. 본 연구에서 제안한 정착구 형상을 사용하였을 때 발생하는 최대파열응력이 기존의 정착 구를 사용한 경우와 비교하여 정착구역내의 최대파열응력이 감소함을 확인하였다. 또한 본 연구의 정착구 형상을 사용하는 경우 최대파열응력 산정을 위해 AASHTO 및 기존 연구자들의 파열력 산정식을 통해 산출된 파열력을 비교 및 분석하였다. 그 결과 정착구 형상에 따른 위치계수를 수정한 파열력 산정식을 적용할 경우 정착구역이 효율적인 보강설계가 가능할 것으 로 판단되었다.

In this study, load transfer tests based on KCI-PS101 were conducted to verify the performance of spiral anchorage zone reinforcement for banded post-tensioning (PT) monostrands. With results, the compressive strength of spiral reinforcement was increased by about 20% than that of specimens with two horizontal steel bars and 8% than that of U-shaped bars. Advanced spiral reinforcement for corner increases compressive strength and can resist the spalling forces or fall-out effect at the corner by shear. The ratio of maximum load to amount of steel of the spiral reinforcement is about twice than that of U-shaped reinforcement. With increase of compressive strength capacity and improvement of constructability, the spiral reinforcement is considered to have advantages of promoting the performance of PT anchorage zone compared to conventional methods.

In this paper, a 2-DOF electromechanical impedance model of PZT material-aluminum interface member is proposed. The primary motivation is to control the effective frequency range in impedance-based local health monitoring practices. The proposed method focuses on the predetermination of the effective frequency band and the wireless impedance sensing possibility for damage detection in structural connections like tendon anchorage, etc. Firstly, a 2-DOF impedance model is proposed for modelling the PZT interface-host structure system. Secondly, the prototype design of the PZT interface is developed based on the analysis of the 2-DOF impedance model and the local dynamic characteristics of the composite aluminum interface-host structure system. Finally, the feasibility of the proposed 2-DOF impedance model is numerically verified by predetermining the effective frequency band for the impedance monitoring in a cable-anchorage connection.

Simulation studies were performed to study the possibility of tensile force monitoring with piezoelectric sensors attached on anchorage devices of bonded tendon systems. The results showed that the impedance signals from piezoelectric sensors has sensitivity enough to evaluate the effective tensile force.