시공성이 개선된 선설치 인서트 앵커에 대한 인장 및 전단 성능평가

Abstract

A new headed cast-in specialty insert (new insert anchor) with significantly improved workability has recently been developed in Korea, and it was devised for fixing lightweight suspended piping trapeze restraint installations. Concrete anchors, such as new insert anchors, must safely transmit seismic loads acting on non-structural components to structural members. Therefore, the importance of their design and construction is significant. However, the current Korean anchor design standards do not include headed cast-in specialty insert type, and studies on their detailed behavioral characteristics and performance are insufficient. Based on the above background, this study conducted simulated seismic tests on newly developed insert anchor and evaluated their detailed behavioral characteristics and performance. First, this study evaluated the fastening performance of the insert shaft and threaded rod through cyclic tension loading experiments according to AC 446. This experiment is summarized in Chapter 3. All three inserts reached the target maximum load without significant damage. The results confirmed that the insert had sufficient tension itself. Subsequently, according to ACI 355.2 and ETAG 001 Annex E, which are widely applied in existing anchor qualification tests, simulated seismic tests were conducted on new insert anchors in cracked concrete. Tension experiments are summarized in Chapter 4, and shear experiments are summarized in Chapter 5. The monotonic tension and shear experiments were conducted on five specimens, respectively, and the observed failure modes matched those predicted by the current Korean anchor design standards. The measured maximum strength was compared with prediction based on design standards and revealed minimal differences. However, under tension load, it was observed that the concrete failure area exceeded the projected area of current design standards. The cyclic loading experiments of this study were performed by applying the loading protocol of ACI 355.2 and ETAG Annex E, and additionally the quasi-static loading protocol of FEMA 461. Cyclic loading experiments were conducted based on the results of the monotonic loading experiments. All tension and shear specimens failed with respectively same as monotonic loading experiments, regardless of the applied loading protocol type. It also confirmed that the performance reduction of the new insert anchors due to the cyclic load rarely occurred. In addition, the performance measured in these cyclic loading experiments was minimal differences depending on the applied loading protocols. However, the quasi-static loading protocol of FEMA 461 has the economical advantages of anchor qualification tests.