유한요소 해석을 이용한 WUF-W 접합부 최적의 파단 예측 반응지표 선정

한상환,김영우,김태오,Han, Sang Whan,Kim, Young Woo,Kim, Tae O 한국지진공학회 2017 한국지진공학회논문집 Vol.21 No.5

The WUF-W moment connection is a pre-qualified connection that can be used for special moment frames specified in current seismic design specifications. Since the stress distribution near the connection varies according to access hole configuration, the cyclic performance of WUF-W connections is strongly affected by the access hole configurations. To evaluate the connection performance according to various access hole configurations, it is expensive to conduct experiments with many connection specimens. Instead, finite element analyses (FEA) can be performed. Throughout the FEA, stress and strain distribution in the connection can be monitored at each loading step. The purpose of this study is to construct nonlinear 3-dimensional FE models for accurately predicting the cyclic behavior of WUF-W connections. For predicting connection fracture using FEA, an appropriate response index detecting the incidence of connection rupture is proposed.

WUF-W 접합부의 액세스 홀 형상변수 타당성 평가를 위한 경험식 제안

한상환,윤용,Han, Sang Whan,Yoon, Yong,Kim, Y. Debbie 한국강구조학회 2017 韓國鋼構造學會 論文集 Vol.29 No.4

WUF-W 접합부는 부재의 접합이 모두 용접으로 이루어진 접합부이며, 특수모멘트골조(SMF) 인증접합부 중 하나이다. 하지만 선행 연구들을 통해 일부 WUF-W 접합부 실험체가 4% 층간변위비의 특수모멘트골조(SMF) 요구성능을 만족하지 못하였으며, 이는 액세스 홀 형상과 연관이 있음이 보고되었다. 본 연구에서는 비선형 유한요소 해석을 이용하여 WUF-W 접합부의 요구성능을 만족하기 위한 주요 액세스홀 형상변수의 허용범위를 결정하였다. 또한 WUF-W 접합부 설계과정에서 주요 액세스 홀 형상변수의 타당성을 평가할 수 있는 간단한 경험식을 제안하였다. The welded unreinforced flange-welded web(WUF-W) connection is an all-welded moment connection, which is qualified for special moment frame(SMF) connections. However, previous studies reported that some WUF-W connections did not meet the drift requirement specified for SMF connections and such unexpected connection performance was resulted from weld access hole geometry. The objective of this study is to determine the permissible ranges of major access hole parameters such as access hole slope and the length of flat portion that lead to the satisfactory performance of WUF-W connections using Nonlinear finite element analyses are conducted. This study also proposes simple empirical equations to check the validity of access hole parameters to be selected in design process.

Post-Northridge WUF-B 접합부 골조의 내진 성능 평가

한상환,문기훈,정지은,이기학,Han, Sang Whan,Moon, Ki Hoon,Jung, Ji Eun,Lee, Ki Hak 한국강구조학회 2007 韓國鋼構造學會 論文集 Vol.19 No.6

본 연구에서는 Welded Unreinforced Flange-Bolted web(WUF-B) 접합부로 설계된 골조의 내진 성능 평가를 수행 하였다. WUF-B 접합부의 설계는 FEMA 350에서 제시한 방법을 사용하였으며, FEMA 350에 따르면 WUF-B 접합부 골조를 보통모멘트 골조(Ordinary Moment Resisting Steel Frames: OMFSFs)로 사용을 제한하고 있다. 이를 위해 WUF-B 접합부 실험결과를 바탕으로 패널존 강도 비를 변수로 하여 Post-Northridge WUF-B 접합부 해석 모델을 제안하였다. 이 해석 접합부 모델을 이용하여 SAC Phase II에서 사용된 3층, 9층 골조를 모델링 하고 내진 해석을 수행하였다. 해석 방법 중 비선형 정적 푸쉬오버 해석을 통하여 Post-Northridge 접합부 골조의 연성능력과 최대 모멘트 강도비, 최대 층간변위비를 구하였고, Incremental Dynamic Analysis(IDA)를 통해 각 성능 레벨(IO, CP)지점에서의 최대 층간변위비를 구하였다. 해석 결과는 Pre-Northridge 접합부 골조와 ductile 접합부 골조의 성능과 비교 검토 하였으며 접합부 상세 보강이 이루어진 Post-Northridge 접합부 골조의 성능이 Pre-Northridige 접합부 골조보다 향상된 것을 확인 할 수 있었다. The purpose of this study is to evaluate the seismic performance of the frame which is assumed to be used with Welded Unreinforced Flange-Bolted web (WUF-B) connections and detailed in compliance with FEMA 350 recommended seismic design criteria. In FEMA 350, these types of connections are only valid for Ordinary Moment-Resisting Steel Frames (OMRSFs). For this purpose, based on test results, we proposed an analytical model for the Post-Northridge WUF-B connections with different panel zone strength ratios. Using the connection model, SAC Phase II three and nine-story frames were modeled and analyzed. From a nonlinear static pushover analysis, ductility, maximum strength, and the maximum interstory drift ratio were investigated for buildings with Post-Northridge details. Moreover, the maximum interstory drift ratio of each performance level (IO and CP) was also investigated through Incremental Dynamic Analysis (IDA). Analytical results were compared with those of buildings with either Pre-Northridge connection or ductile connections with no fracture. The analytical results showed that buildings with Post-Northridge WUF-B connections provide superior strength and interstory drift ratio capacity than buildings with Pre-Northridge WUF-B connections.

반복하중을 받는 고강도강 기둥을 적용한 WUF-W 접합부의 이력 거동

한상환,김종민,문기훈,Han, Sang-Whan,Kim, Jong-Min,Moon, Ki-Hoon 대한건축학회 2011 대한건축학회논문집 Vol.27 No.7

This study's purpose is to evaluate the seismic performance of Welded Unreinforced Flange-Welded Web connections with the column composed of high-performance steel. The study involved the inelastic cyclic loading test of 4 full-scale exterior connection specimens to evaluate the effect of column strength and beam depth. All specimens are designed as strong column-weak beam and strong panel zone. They are observed at the peak deformation of each cycles with the unaided eye. 3 of 4 specimens including 2 specimens consisted of high-performance steel column are achieved total story drift of 0.04 rad or more prior to failure. The test results showed that ductility capacity of connections with high-performance steel column is sufficient in light of current AISC seismic design. Energy dissipation in specimens consisting of high-performance steel column is less than those of normal strength steel column. Also, K120TG, which is the developed weld metal for 800MPa grade steel, is estimated as good material in case of welding between normal strength steel and high-performance steel through this study.

리브 보강된 콘크리트 충전 HSS 가새부재의 이력 거동

한상환,여승민,김욱태,Han, Sang Whan,Yeo, Seung Min,Kim, Wook Tae 한국강구조학회 2005 韓國鋼構造學會 論文集 Vol.17 No.1

The purpose of this study is to improve the seismic behavior of the bracing members. Lee and Goel's (1987) concrete filling in the hollow structural section (HSS) reduced the severity of local buckling and increased the fracture life. However, concrete filling in the HSS did not prevent the occurrence of local buckling in the midsection of the bracing member, which resulted in continuous strength degradation. This study investigated the seismic behavior of the concrete-filled HSS bracing member, which is reinforced by ribs in the midsection of the bracing member. The main variable of the specimens is rib length. The test results showed that buckling mode, cyclic compression strength, and energy dissipation capacity of the bracing members were affected by rib length. Specimen reinforced with ribs with a length of 63% had better structural performance. 본 연구의 목적은 가새 골조에서 사용되는 가새 부재를 보강하여 가새 골조의 이력 거동을 향상시키는 것이다. HSS(Hollow Structural Section) 가새 부재는 국부 좌굴의 발생으로 인하여 인장측 성능에 비해 압축측 성능이 취약한 단점이 있다. 국부 좌굴의 심각성을 감소시키기 위하여 가새 부재에 콘크리트를 충전하는 방법이 사용되었다. Lee and Goel(1987)의 연구 결과에 따르면 콘크리트 충전은 HSS 가새 부재의 국부좌굴의 심각성을 감소시켜 파괴 수명을 증가시켰으나, 가새 부재 중앙부의 국부좌굴을 방지하지 못하여 지속적인 압축 강도의 저감이 나타났다. 따라서 본 연구에서는 가새 부재의 압축 강도를 증가시키고 중앙부의 국부 좌굴을 방지하기 위하여 콘크리트 충전 HSS 가새 부재의 중앙부를 리브로 보강한 실험체를 제작하여 실험하였다. 이를 위하여 리브 보강길이를 변수로 한 총 4개의 실물 크기의 가새 부재를 제작하였다. 하중은 압축과 인장이 대칭인 하중이력을 사용하였다. 본 실험에서 좌굴 모드, 사이클 최대 압축강도와 에너지 소산능력에서 나타난 리브 보강 가새 부재의 성능은 리브 보강길이에 따라 다르게 나타났으며, 63%의 길이로 보강한 실험체가 가장 우수한 성능을 나타내었다.

중공 전이슬래브의 휨 및 전단강도

한상환,유연호,박영미,김준삼,임주혁,Han, Sang-Whan,Rew, Youn-Ho,Park, Young-Mi,Kim, Jun-Sam,Im, Ju-Hyeuk 대한건축학회 2011 대한건축학회논문집 Vol.27 No.2

The transfer slab system is widely used in high apartment building and is a structural system that transfers the loads from the upper shear wall structure to the lower columns. This system has convenience in construction but is noneconomic system due to a very thick slab. The fault is overcame by voids in the slab. Because the structural performance is, however, decreased by the voids, the strength prediction of the void slabs is very important. However, the current code doesn't provide a clear calculation provision for the strength of void slabs. In this study, experimental study was conducted to investigate the flexural strength and the one-way shear strength of the void transfer slab. The flexural and the shear strength of the specimens was predicted by current code and prior researches. In result, the flexural strength of void slabs is accurately predicted by the equation of the current code, and the shear strength is accurately predicted by shear equation of the code considering slab effective section of 45 degree from a support.

대각보강된 연결보의 비선형 모델 매개변수 경험식 제안

한상환(Han, Sang Whan),조은선(Cho, Eun-seon),구수현(Koo, Su-hyun) 대한건축학회 2021 대한건축학회논문집 Vol.37 No.12

Nonlinear static and dynamic analyses are commonly used in seismic performance evaluation. To achieve the accurate results of nonlinear analyses, modeling parameters should be determined accurately for structural members. In this study, the values of modeling parameters provided in ASCE 41-17 for diagonally reinforced coupling beams (DRCBs) were evaluated whether those values accurately reflect the measured behavior of DRCBs. To imporve the accuracy, this study proposed empirical equations to determine the values of modeling parameters for DRCBs. For this purpose, the test results of 52 DRCB specimens were collected, from which the parameter values of c, d, e, Q<SUB>max</SUB>, I<SUB>e</SUB>/I<SUB>g</SUB> were estimated for individual specimens. The empirical equations of these parameters were developed based on the measured values. The accuracy was verified by comparing the calculated and measured values of modeling parameters.

우리나라 내진설계 현황 및 문제점

한상환(Han Sang Whan) 대한건축학회 2011 建築 Vol.55 No.5

기둥 전단변형에 대한 고려가 철골 특수모멘트골조의 붕괴위험도 평가에 미치는 영향

한상환(Han, Sang Whan),김태오(Kim, Taeo) 대한건축학회 2022 대한건축학회논문집 Vol.38 No.12

내진인증접합부 Welded Unreinforced Flange Welded Web (WUF-W) 모멘트 접합부 소개

한상환(Sang Whan Han) 한국강구조학회 2012 韓國鋼構造學會誌 Vol.24 No.5