비탄성 국부좌굴을 고려한 철골 모멘트 접합부의 회전능력에 대한 변수 연구

이경구,Lee, Kyung Koo 한국강구조학회 2008 韓國鋼構造學會 論文集 Vol.20 No.5

동반논문(모델개발)에서는 특별철골모멘트골조의 강접합 보-기둥 접합부의 회전능력을 예측하기 위한 해석모델을 제안하였다. 본 논문에서는 접합부 회전능력 기준으로 두 개의 극한상태를 고려하였다. 첫째, 보 단면의 국부좌굴로 인해 공칭소성강도까지 강도저하가 발생하였을 때를 회전능력으로 보는 강도저하 극한상태를 고려하였다. 둘째, 큰 진폭의 변형이 몇 번 반복 후에 좌굴된 플랜지에서 소성변형률 축적으로 야기 되는 저주기 피로 파단을 극한상태로 고려하였다. 두 극한상태까지 제안한 모델을 이용하여 단조증가하중 및 반복하중하에 일련의 해석을 수행하였다. 실무설계에서 사용되는 범위안의 다양한 H-형강 보를 모델링한 후, 플랜지 및 웨브 폭-두께비와 같은 보 단면의 기하학적 변수가 WUF-W 접합부의 회전능력과 저주기 피로수명에 미치는 영향을 관찰하였다. In the companion paper (Model Development), an analytical model estimating the available rotation capacity of fully restrained beam-column connections in special steel moment-resisting frames was proposed. In this paper, two limit states were considered as the connection rotation capacity criteria: (i) strength degradation failure when the strength falls below the nominal plastic strength due to the local buckling of the beam's cross-section and (ii) low-cycle fatigue fracture caused by plastic strain accumulation at the buckled flange after only a few cycles of high-amplitude deformation. A series of analyses are conducted using the proposed model with two limit states under monotonic and cyclic loadings. Beam section geometric parameters, such as flange and web slenderness ratios, varied over the practical ranges of H-shapedbeams to observe their effect on the rotation capacity and low-cycle fatigue life of pre-qualified WUF-W connections.

비탄성 국부좌굴을 고려한 철골 모멘트 접합부 회전능력 평가를 위한 모델 개발

이경구,Lee, Kyung Koo 한국강구조학회 2008 韓國鋼構造學會 論文集 Vol.20 No.5

잘 설계된 철골 모멘트 접합부의 경우, 유효회전능력에 도달하기 전에 국부좌굴이 발생하고 비탄성 후좌굴 변형이 접합부 회전능력을 정의하는데 중대한 역할을 한다. 이 연구에서는 국부좌굴로 인한 강도저하와 보 소성힌지의 회전을 모델링하여, 단조증가하중 및 반복하중이 작 용하는 특별철골모멘트골조의 강접합 보-기둥 접합부의 회전능력을 예측하기 위한 근사적 해석모델을 제안한다. 제안된 항복선 소성힌지 모델은 좌굴된 소성힌지부의 형상에 기초하여 항복선과 소성존으로 구성되고, 소성메커니즘을 통해 국부좌굴후의 거동까지 포함한 모멘트-회전각 관계를 제 공한다. 향상된 WUF-W 와 RBS 접합부를 위해 제안된 모델을 개발한 후 실험결과와 비교를 통해 검증하였다. 동반논문(변수연구)에서는 광범위 한 H-형강의 기하학적 변수 따른 접합부 회전능력에 대하여 논의하였다. Well-designed steel moment connections will undergo local buckling before they exhaust their available rotation capacity, and inelastic post-buckling deformation plays a major role in defining the connection rotation capacity. An approximate analytical method to model strength degradation and failure of beam plastic hinges due to local buckling and estimation of the seismic rotation capacity of fully restrained beam-column connections in special steel moment-resisting frames under both monotonic and cyclic loading conditions is proposed in this study. This method is based on the plastic mechanism and a yield line plastic hinge (YLPH) model whose geometry is determined using the shapes of the buckled plastic hinges observed in experiments. The proposed YLPH model was developed for the improved WUF-W and RBS connections and validated in comparison with experimental data. The effects of the beam section geometric parameters on the rotation capacity were discussed in the companion paper (parametric studies).

근접폭발하중에 대한 구조물해석 최근 연구동향

이경구,신진원,Lee, Kyung-Koo,Shin, Jin-Won 한국공간구조학회 2015 한국공간구조학회지 Vol.15 No.3

콘스탄티누스 기진장의 작성목적

이경구 ( Kyung Koo Lee ) 한국서양중세사학회 2003 西洋中世史硏究 Vol.0 No.11

The Donation of Constantine has been regarded as the most famous forgery of the entire Middle Ages. The document seemend to be forged according to the thorough program of the papal curia in the middle eighth century. The author fabricated the document for the purposes as follows. First, the Donation purported to confirm that Roman Catholic religion is orthodoxy. The Roman Church suffered a lot of difficultie due to the Arius heresy of Lombards and the iconoclasm of the Constantinople church. The author wanted to secure the dogmas of the Roman Church to be orthodoxy instead of the heresies. Second, the Donation intended to secure the primacy of the Roman Church. The papacy hoped to unifiction of the christian faith under the initiative of the Roman Church holding back rival churches such as the Byzantine church. The desire of the papal curia was echoed in the document. Third, the Donation was fabricated as an evidence of the papacy`s temporal right in Italy including the city of Rome. The Byzantine emperors had claimed their rights to rule the Italian peninsula as the legal successors of the ancient Roman emperors. The curia was in dire need of an evidence for the secular rulership in Italy instead of the Byzantine Empire. The evidence was also required aginst the Franks because they could claim their rights to the Italian territory once they subjugated Lombards in the north Italy.

스테파누스 2세와 피핀의 상봉: 그 역사적 의미

이경구 ( Kyung Koo Lee ) 한국서양중세사학회 2002 西洋中世史硏究 Vol.0 No.9

Italy was a land of conflicting dilemmas in the middle of the eighth century. Because three powers of the Byzantines, the Lombards, and the Papacy competed one another to hold hegemony of the Italian peninsula. The Byzantine Emperors, as the legitimate successors of the ancient Roman Emperors, claimed their theoretical rights to rule the peninsula. But the Lombard kings who had strong troops tried to seizure the whole Italy by the sword. The Popes, on the other hand, wouldn`t accept not only the rult of the Byzantins but also that of the lombards because the wanted to rule over the whole province of Italy. In this tripartite relation Pope StephenⅡ took the initiztive in Italy by the tools of diplomacy. It was impossible for the Pope to expel the Byzantines and the Lombards from the peninsula because he had not any military means. He solved the difficult situation receiving the military assistance from the Frankish king PepinⅢ. Stehpen, that is, rescued the Church and the Papac by means of his skill diplomacy. There were secret contacts between the papal curia and the pepin`s palace before Stephen visited the Frankish kingdom. Both exchanged Letters and embassies each other with the utmost secrcy without making known those things to either Byzantines or Lombards. Stephen`s secret diplomacy obtained excellent results. The Papacy could be raised to the position of the head in the Italian peninsula instead of Byzantines and Lombards In relation with Pepin the Stephen also enjoyed actual papal supremacy. The evidence that the Pope claimed his supremacy to the Frankish king was indeed the Donation of Constantine and the Petrine Theory. The Pope`s predominant position was evidently expressed in the rite of groom service that Pepin performed before Stephen when they met each other at the first time. Stephen succeed to make Pepin protector of the see of St. Peter as a result of the meeting between the two. The Pope charged the Frankish king with the duty of service for the Roman Church and the Papacy. The Popes such intention was symbolically reflected in the unction which Stephen edstowed on pepin and his two sons at St. Denis and the title `patricius Romanourum` which he conered on them after the rite. In severe danger Stephen thus saved the Duchy of Rome and the Roman Church receiving the military assistance from Pepin. Pepin also made some profits by foreing cooperation with Stephen though the Frankish king acted passively in relation with the Pope. Consecrated by the Pope the Frankish king now became a holy king. and then as a capacity of a holy king Pepin was properly able to conduct the Chirstian people living in the western Europe. Making successful expeditions to italy he not only consolidated his position in the Frankish kingdom but also secured a firm foothold to take a significant role in the western society. In these aspects the meeting between Stephen and Pepinwas the important accident that decided on the future course of the history of the Papacy and furthermore of the western Europe.

주열식공법 엄지말뚝을 위한 고강도 신형상 합성파일 (S-Pile)의 휨성능 평가

이경구 ( Lee Kyung-koo ),김대희 ( Kim Dae-hee ),주은희 ( Joo Eun-hee ),김영기 ( Kim Young-gi ),김봉찬 ( Kim Bong-chan ),이지훈 ( Lee Ji-hoon ) 한국건축시공학회 2021 한국건축시공학회 학술발표대회 논문집 Vol.21 No.1

In Korea, many buildings are built with underground spaces and cast-in-place pile method is mostly applied in the temporary retaining walls for the underground space construction. A H-shaped steel section is generally embedded in the soldier pile in the C.I.P method. In this study, a new and economical section with high strength steel replacing the H-shaped section was proposed and its flexural capacity was evaluated experimentally. The new section is the concrete-filled composite section with pentagonal thin plate and thick flange plate. Test results showed that the proposed section has an excellent flexural strength and ductility.

8세기 중엽 교황의 리더십

이경구(Lee Kyung-Koo) 호서사학회 2009 역사와 담론 Vol.0 No.54

In the middle eighth century the Roman Church had to do something to survive in the face of external pressures from three big powers, Byzantine Empire, Lombard Kingdom, and Frankish Kingdom, which competed with each other to gain the hegemony of Italian peninsula. In the religious area, Pope Gregory Ⅱ, unlike his predecessors, decided to protest against Byzantine Emperors who have taken the initiative in the religious problems of the western Church until the early eighth century and presided all ecumenical councils solving the dogma problems to their own will. The Pope successfully showed his protest to the forcible demand of heavy taxation and iconoclasm to Italians. Successors of Gregory Ⅱ strengthened the resistance of Italians against the Emperors and raised up the problems as the common interests of the whole Italians. In the process of the struggle with the Emperors, the consciousness that Italia was a different national entity from the Byzantine Empire began to grow. The popes at last succeeded to hold fast to the tradition of the veneration of icons against iconoclasm of Byzantine Emperors, to distinguish the Roman Church from the Constantinople which destroyed icons, and so to lead the discriminated western Church. In the political field, Popes also began to take the initiative through the politics of power-balance when they faced military threats from Lombard Kingdom. Popes, as representatives of Emperors, made a good use of Frankish Kingdom to remove the threats not to secure Emperors's interests but to establish his own political leadership and safety. Hitherto many scholars have insisted that the popes continued to be loyal to the Byzantine Emperors until the middle eighth century. In my opinion, however, papal loyalty to the Emperors were liquidated in this period by their skillful tactics. The popes superficially acted as the representatives of the Emperors in Italian problems but they actually took an advantage of the office of the Byzantine Empire for the interest of the Roman Church. Adopting the politics of the balance of powers the popes could accomplish what they wanted for the Roman Church and establish what they looked for in western Europe, the foundation of temporal power that they will hold in the future. In short, all these prove that the popes of the mid-8th century displayed a distinguished leadership.

프리드리히 바바롯사의 황제권 이론

이경구(Kyung Koo Lee) 한국서양중세사학회 1997 西洋中世史硏究 Vol.- No.2

N/A

포스트 코로나 시대 국내 강구조 건축물의 전망과 기대

이경구(Kyung Koo Lee) 한국강구조학회 2021 韓國鋼構造學會誌 Vol.33 No.5

교황 그레고리우스 2세: 충성스런 신하인가, 치밀한 혁명가인가

이경구 ( Kyung Koo Lee ) 한국서양중세사학회 2010 西洋中世史硏究 Vol.0 No.25