Reinforced concrete (RC) moment frames are widely used to resist lateral loads associated with wind and earthquakes. However, most older RC moment frames performed poorly against past earthquakes. In moment frames, beam-column connections play a crucial role in system performance. Among the connections, corner connections are more vulnerable because they are restrained by only two beams and are affected most strongly by bidirectional loading. High-performance fiber-reinforced cementitious composites (HPFRCC) were used in previous studies to improve the seismic performance of older beam-column connections. This study aims to evaluate the level of improvement of seismic behavior of older beam-column connections under bidirectional loading after retrofitted with HPFRCC by comparing the seismic behavior of the HPFRCC connections to beam-column connections used in intermediate (IMF) and special moment frames (SMF). Test results revealed that the seismic behavior of the HPFRCC connections was almost close to that of SMF connections.

In this study, two full-scale gravity load-designed reinforced concrete corner beam-column joints were tested by being subjected to uniand bi-directional cyclic lateral loading. The test variable was loading type: uni- or bi-directional loading. To investigate the effect of the loading type on the cyclic behavior of joint specimens, damage progression, force-deformation relation, contribution of joint deformation to total drift, joint stress-strain response, and cumulative energy dissipation were investigated. The test data suggest that bidirectional loading can amplify damage accumulation in the joint region.

The coner high column method that is used in the multi-roof building Sungryemoon seems to have been used for the first time during the Choseon Dynasty, and it's characteristics and trend of usage are studied in this paper. In the results, it was confirmed that the coner high column method is economic and structurally safe, and selectively combines the structural factors used in the Chinese seats. It was found that this method was a newly adopted construction method to effectively express the authority of the country with the establishment of a new dynasty. Also the meaning of the method could be guessed since it was continuously used in important structures from the Choseon Dynasty to the Daehan Empire, in spite of the new multi-roof building technologies.

본 연구에서는 일반강도 슬래브가 기둥 사이로 지나가는 형태의 모서리 기둥에 대한 유효압축강도 예측식을 개발하고자 하였다. 예측식 개발을 위해서 고강도 기둥-일반강도 슬래브 접합부와 조적조 구조의 유사성을 이용하였으며, 이에 더하여 기둥 단면치수에 대한 슬래브 두께의 형상비를 고려하였다. 제안된 식에 의한 예측값과 실험값의 비교를 통해 신뢰도를 확인하였으며, 설계기준 및 타 연구자들에 의한 제안식과 비교를 통해 우수성을 검증하였다. 연구결과, 제안식은 예측치에 대한 실험값의 비가 평균 1.02, 표준편차 0.15를 보여 콘크리트 구조기준 (2012)을 포함한 타 유효압축강도 예측식들에 비해 정확도 및 일관성 모두 우수한 결과를 나타냈다.