In this research, the concrete breakout strength in tension of cast-in-place anchors (CIP) is experimentally investigated to be used as fundamental data for the seismic fragility analysis of equipment in nuclear power plants. Experimental variables are chosen, such as the embedment depth of the anchor, single/group anchor configurations, diameter of the head plate, and crack width. Monotonic and cyclic loading are applied to all types of specimens. As measured from the experiments, concrete breakout strength in tension is 1.5 to 2 times higher than the expected strengths from concrete capacity design (CCD) method-based model equations. In alignment with the model’s predictions, concrete breakout strength increases with deeper embedment depth, and the strength of group anchors also increases based on the expansion of the projected concrete failure area. This study also explores the effects of head plate diameter and crack width, which are not considered in the model equation. Experimental results show that the diameter of the head plate is not directly correlated to the concrete breakout strength, whereas the crack width is. The presence of cracks, with widths of 0.3 mm and 0.5 mm, leads to reductions of approximately 7% and 17%, respectively, compared to single anchors in non-cracked concrete.

Recently, a novel cast-in specialty insert was developed in Korea as an anchor for lightweight pipe supports, including fire-protection pipes. As these pipe supports and anchors play a critical role in transferring loads of fire-protection pipes to structural members, it is crucial to evaluate their seismic performance before applying the newly developed insert. In this study, the seismic shear performance of the insert anchors was evaluated through cyclic loading tests based on the loading protocols of ACI 355.2 and FEMA 461. Initially, five monotonic loading tests were conducted on the insert anchors in cracked concrete, followed by cyclic loading tests based on the monotonic test results. The findings revealed that the insert anchors exhibited negligible decrease in shear strength even after cyclic loading. Furthermore, a comparison of the maximum load and displacement of the insert anchors obtained under the loading protocols of ACI 355.2 and FEMA 461 was performed to investigate the applicability of the FEMA 461 loading protocol for anchor performance evaluation.

FRP를 이용한 보강법 중에서도 기존에 일반적으로 행해진 보강법은 Plate 또는 Sheet의 형태로 콘크리트 표면에 부착하여 추가적인 강도를 발현하도록 하는 것이다. 그러나 조기 박락파괴, 부착면의 정리, 보강 단부의 앵커시공, 부착면에 대한 내화처리 등의 어려움이 많다. 이러한 문제점들에 대한 방안으로 막대(Rod) 형태인 CFRP-Rod를 보강모체에 홈을 파고 매립하는 NSMR(Near Surface Mounted Reinforcement)공법이 제안되었고, CFRP-Rod의 보강량, 길이, 간격 등의 변수에 의한 휨보강 능력의 평가에 대한 연구가 이루어져왔다. 그러나 구조물에서 CFRP-Rod의 보강은 어느 정도의 하중이 보강부위에 계속 재하된 상태로 보강이 이루어지게 되므로 본 연구에서는 보강전에 가해지는 선하중(Pre-loading)의 크기를 주요변수로 선하중의 크기에 따른 구조물의 거동 특성을 분석하고자 하였고, 선하중의 크기의 결정은 무보강 시험체의 공칭모멘트와의 비로 결정하였다.