DOWNLOAD

• 저자: 이호준, 박홍근, 황현종, 김창수
• Abstract: Existing experimental results show that carefully designed RC column-to-steel beam (RCS) joints have high seismic resistance comparable to those of traditional steel or RC frames with seismic details. However, such high seismic performance requires complicated and expensive strengthening details, which causes difficulties in fabrication and construction. This study investigated simpler strengthening methods, targeting moderate seismic capacity. Four interior RCS joint specimens were tested under cyclic lateral loading. The major test parameters were the strengthening details of the beam–column joint such as face bearing plates, transverse beams, and headed studs. The test specimens with the proposed methods exhibited good deformation capacity exceeding 4.0% story drift ratio after yielding of the beams and beam–column connection. However, the peak load did not reach the nominal strength based on the beam plastic moment due to early joint damage. The failure modes and test strengths were compared with the predictions of ASCE design guidelines. On the basis of the results, design recommendations for the simplified connection details were proposed.

<DOWNLOAD>

• 경사단부강판 보 이음을 갖는 강재 보-기둥 모멘트접합부의 내진실험(Seismic Tests of Steel Beam-to-column Moment Connections with Inclined End-plate Beam Splice)

• 저자: 임종진, 김동관, 이상현, 박철수, 이창남, 엄태성

• Abstract: A beam splice method using inclined end-plates and high-strength tension bolts was developed. The end-plates welded to a bracket and a spliced beam are connected each other by using the tension bolts. In the present study, six exterior beam-to-column moment connections were tested under cyclic loading. Test parameters were the end-plate details and bolt arrangements. All specimens were designed so that moment resistances of the end-plates and bolts were greater than the required moment at the beam splice, in accordance with the design methods of AISC Design Guide 4. Test results showed that in the beam splices with the extended end-plates, the beam moment successfully transferred to the bracket, without any defeats such as excessive prying action of the end plates and brittle failure at the end plate-to-beam flange weld joints. However, the deformation capacities of the overall beam-to-column connections were limited due to the brittle failure of the beam-to-column flange weld joints. From the test results, recommendations for seismic design and detailing of the beam-to-column moment connection with inclined end-plate beam splice were given.

<DOWNLOAD>

• 복합모멘트접합을 갖는 콘크리트 충전 보-기둥 합성접합부의 반복하중 실험(Cyclic Loading Tests of Concrete-Filled Composite Beam-Column Connections with Hybrid Moment Connections)

• 저자: 임종진, 김동관, 이상현, 이창남, 엄태성

• Abstract: In the present study, hybrid moment connections of welding and bar reinforcement for composite beam-column connections were proposed. Concrete-filled octagonal tube and U-section were used for the column and beam, respectively. In the beam-column connection, the top flange and web of the beam U-section were connected to the column plate by welding. However, to reduce stress concentration at the weld joints, the bottom flange of the beam was not welded to the column plate. Instead, to transfer the tension force of the beam flange, reinforcing bars passing through the column plate were used. Four exterior connections with conventional welded and hybrid moment connections were tested under cyclic loading and their cyclic behaviors were investigated. The test results showed that the hybrid moment connections successfully transferred the beam moment to the column. The strength and ductility of the hybrid moment connections were comparable to the conventional welded moment connection with exterior diaphragm; however, the connection performance was significantly affected by the details of the hybrid moment connection.

• <DOWNLOAD> Cyclic Loading Test for Beam-Column Connections of Concrete-Filled U-Shaped Steel Beams and Concrete-Encased Steel Angle Columns

-저자 : 황현종, 엄태성, 박홍근, 이승환, 김형섭

Prefabricated steel–reinforced concrete angle columns and concrete-filled U-shaped steel beams were recently developed for efficient steel-concrete composite construction. In the present study, seismic details of TSC beam–PSRC column connections were developed, taking into consideration constructability and cost efficiency. A cyclic loading test was performed on the beam-column connections to investigate load-carrying capacity, deformation capacity, failure mode, and energy dissipation capacity. For the test parameters, the connection type (interior or exterior) and the depth of the TSC beams were considered. The test results showed that the deformation and energy dissipation capacities of the specimens satisfied the requirements for intermediate moment frames specified in the AISC standard. Further, the moment-carrying capacities predicted using plastic stress distribution were found to be in agreement with the test results. The joint shear capacities of the specimens were evaluated according to ASCE design guidelines.

<DOWNLOAD>

• 철골 철근콘크리트 기둥과 TSC 보를 이용한 기둥 보 접합부에 관한 실험적 연구

– 저자 : 서동민, 함정태, 김성배, 이창남, 김상섭

본 연구는 U자형 강판을 이용한 합성보(이하 TSC 보)와 철골 철근콘크리트기둥(이하 SRC기둥)의 접합부에 대한 반복가력 실험을 통해 접합부의 구조 성능 평가를 하고, 구조설계에 필요한 기초 자료를 제시하고자 하였다. TSC 보 기둥 보 접합부의 성능 평가를 위해 실시한 철골 콘크리트 기둥 TSC 보 접합부 실험결과는 다음과 같다. 첫째; TSC 보를 이용한 기둥-보 접합부 3개 실험체 모두 정-부모멘트 구간이 0.04 radian 까지 전소성모멘트의 80% 이상을 확보하며, 급격한 하중 저감 없이 안정적인 거동을 하였다. 둘째; TSC 보를 이용한 기둥 보 접합부는 상부 철근이 인장을 받는 부 휨 모멘트 작용 시 최대내력은 H형강 보를 적용한 실험체 보다 150% 이상 크게 증가하였다. 이것은 TSC 보 내부에 타설 된 중립축 하부의 콘크리트가 부 모멘트 작용 시 압축으로 기여하기 때문이다.

In this study, experiment is cycle loading about TSC beam with slab reinforced influence to capacity of connection behavior. Purpose of this experiment is that TSC beam-to-SRC column connection is satisfied to ‘Seismic Provision for Structural Steel Building’ in AISC and SAC. The results can be shown as follows; The major causes to fail of specimens are local bucking and cracks on the top slab concrete due to negative bending moment. And the detail of composite beam-to-column connection can achieve the SMF(special moment frame) completement with ‘Seismic Provision for Structural Steel Building’.

<DOWNLOAD>

• 수평스티프너를 이용한 철골 기둥-보 약축접합부 상세 개발에 관한 연구

– 저자 : 이도형, 함정태, 김성배, 김영호, 김상섭

철골 기둥-보 강축 접합부에 대한 연구는 그 동안 국내외에서 오랜 기간 연구가 진행되어 내진성능 및 접합부의 강도를 개선시킬 수 있는 많은 접합 형식이 개발되어 사용 중에 있으나, 약축 접합 형식에 대한 연구는 거의 없는 실정이다. 또한 현재 국내에서는 시공성을 고려하여 기존의 브라켓형식 용접 접합부를 선호하고 있으나, 용접량이 많아 취성적인 거동이 우려되며 과대 설계된 경향이 있다. 본 연구의 실험 결과에서 기존 브라켓 형식 용접접합은 용접량이 과도한 것으로 나타났으며, 기둥 웨브와 보의 웨브의 용접은 불필요한 것으로 판단된다. 그리고 본 연구에서 제안한 새로운 기둥-보 약축 접합형식들에 대한 실험 결과에서 기존 브라켓형식 용접접합보다 우수한 내력 및 연성을 보유하여 구조적으로 안전함을 학인할 수 있었다.

The strong beam-to-column axis connections in steel structures have been studied for a long time to develop the strength and resistance of the connections. There have been very fow studies, however, related to weak axis connections. Domestically, the bracket type connection is commonly used in weak axis connections to elevate the efficiency of the constructions when the steel structures are constructed. The bracket-type connection detail has been applied moderately to weak axis connections. Therefore, the bracket-type connection in weak axis connections might be brittle and over-designed. The results of this study showed that the welding on the web of the column and the beam was unnecessary. In addition, this study confirmed that the new weak axis connection proposed in this study was superior to the previous connection in terms of strength and ductility.

<DOWNLOAD>

• SRC 기둥 – TSC 보 접합부의 거동에 관한 연구

– 저자 : 김성배, 함정태, 이창남, 김상섭

In this study, experiment is cycle loading about TSC beam with slab reinforced influence to capacity of connection behavior. Purpose of this experiment is that TSC beam-to-SRC column connection is satisfied to ‘Seismic Provision for Structural Steel Building’ in AISC and SAC. The results can be shown as follows; The major causes to fail of specimens are local buckling and cracks on the top slab concrete due to negative bending moment. However, concrete filled with U-type steel plate can be resisted local buckling by sharing compression force due to negative bending moment. And the detail of composite beam-to-column connection can achieve the SMF(special moment frame) completement with ‘Seismic Provision for Structural Steel Building’.

<DOWNLOAD>

• 콘크리트채움 U형 강재보-강재기둥 합성 내진접합부에 대한 주기하중 실험

– 저자 : 박홍근, 이철호, 박창희, 황현종, 이창남, 김형섭, 김성배

In this study, seismic resistance of concrete encased U-shaped steel beam-to-steel H-shaped column connections was evaluated.Three specimens ofthe beam-to-column connection were tested undercyclic loading.The compositebeam was integrated with concrete slab using studs. Re-bars for negative moment were placed in the slab. The primary test parameter was the details of the connections, which are strengthening and weakening strategies for the beam  end and the degree of composite action. The depth of the composite beams was 600mm including the slab thickness. The steel beam and there-bars in the slab were weld-connected to the steel column. For the strengthening strategy, cover plates were weld-connected to the bottom and top flanges of the steel beam. For the weakening strategy, avoid using styrofoam box was located inside the core concrete at the potential plastic hinge zone. The test results showed that the fully composite specimens exhibited good strength, deformation, and energy dissipation capacities. The deformation capacity of the beam exceeded 4% rotation angle, which is the requirement for the Special Moment Frame.

<DOWNLOAD>

• PRC 보- 기둥 접합부의 내진성능

– 저자 :  송진아, 박홍근, 이창남, 엄태성

Prefabricated reinforced concrete (PRC) uses prefabricated re-bars for fast construction and cost-saving. In the present study, prefabricated re-bar details for beam-column connection were developed. Cyclic loading tests were performed to evaluate the earthquake resistance of interior and exterior beam-column connections. The beam-column connections were designed in full scale to satisfy the requirements of the special moment frame specified in KCI 2007 and ACI 318-08. For the PRC method, re-bar welding, coupler splice, headed bar anchorage, and high strength steel (SD500W) were used in the specimens. Test results showed that the PRC connections showed deformation capacity greater than the minimum story drift ratio of the special moment frame, 3.5 %, specified in ACI 374.1-05. The load-carrying capacity, yield stiffness, and energy dissipation capacity of the PRC connections were comparable to those of conventional reinforced concrete connection. The major failure modes of the PRC connections were flexural crushing of concrete and re-bar fracture at the beam plastic hinge region. The re-bar welding and coupler splice did not significantly affect the performance of the specimens.

<DOWNLOAD>

• Cyclic Loading Test for Beam-Column Connection with Prefabricated Re-Bar Details

– 저자 : 엄태성, 송진아, 박홍근, 김형섭, 이창남

A Prefabricated Reinforcing Bar Construction (PRC) Method was developed for fast construction and cost savings. In this study, a prefabricated reinforcing bar connection method for the earthquake design of beam-column connections was developed. Three interior and one exterior full-scale beam-column connections, including a conventional reinforced concrete (RC) specimen, were tested under cyclic loading. The test specimens were designed to satisfy the requirement of the special moment frame specified in ACI 318-08. In the proposed connection method, reinforcing bar welding, coupler splice, and headed bar anchorage were used, considering the PRC Method. The test results showed that the story drift ratio of the PRC beam-column connections exceeded 3.5%, which is the requirement of ACI 374.1-05. The load-carrying capacity, yield stiffness, and energy dissipation capacity of the PRC specimens were comparable to those of the conventional RC specimen. The major failure modes of the PRC specimens were flexural concrete crushing and reinforcing bar fracture at the beam plastic hinge region. The welding of the reinforcing bars and the coupler splice did not significantly affect the performance of the specimens.