• Structural Engineering and Mechanics
• /
• 제24권3호
• /
• pp.291-306
• /
• 2006

In order to improve the constructability and meanwhile ensure excellent seismic behavior, several innovative composite connection details were conceived and studied by the authors. This paper reports experimental results and observations on seismic behavior of steel beam bolted to reinforced concrete column connections (bolted RCS or BRCS). The proposed composite connection details involve post tensioning the end plates of the steel beams to the reinforced concrete or precast concrete columns using high-strength steel rods. A rational design procedure was proposed to assure a ductile behavior of the composite structure. Strut-and-tie model analysis indicates that a bolted composite connection has a favorable stress transfer mechanism. The excellent capacity and behavior were then validated through five full-scale beam to column connection model tests.

• 한국산학기술학회논문지
• /
• 제19권7호
• /
• pp.481-492
• /
• 2018

본 강판 콘크리트 합성보는 강판, 콘크리트 및 전단 연결재로 구성되어 2개의 이질 재료를 결합한다. 일반적으로 강판은 기존의 합성보에 용접하여 조립된다. 이 연구에서, SPC 보는 스터드가 없는 강판과 콘크리트로 구성된다. 절곡한 강판은 용접 대신 고강도 볼트로 조립된다. 현장 건설의 작업성을 향상시키기 위해 슬래브와 접합부에 모자 모양의 Cap이 부착되어있다. Cap을 전단연결재로 사용하여 SPC 보의 휨성능을 분석하기 위해 변위 제어 모드에서 단조 하중 2점가력 실험을 수행 하였다. 전단 연결재 유형, 돌출 길이, 강판의 두께의 변수를 갖는 5개의 시험편을 제작하여 시험 하였다. KBC 2009에서 제시하는 전단강도비와 휨강도비의 관계를 분석하였다. 시험 결과로 전단 강도비를 40% 이상으로 나타냈다. 전단 연결재와 Cap을 부착하였음에도 완전합성보로 가정한 휨강도의 70% 이상의 휨강도를 발휘하였다. 또한 Cap이 스터드 보다는 작은 전단강도를 보였으나, Cap이 전단연결재 역할을 하였다. 강판두께를 변수로 한 경우, 완전합성보 대비 약 70%의 휨강도를 발휘하였으며, 유사한 변형성능을 나타내었다. 불완전합성거동함에 따라 국부좌굴이 발생하였으나, 상대적으로 두꺼운 강판의 경우 5% 높은 강도에서 국부좌굴이 발생하였다. 또한 좌굴폭이 15% 감소하였다.

• 한국산학기술학회논문지
• /
• 제19권7호
• /
• pp.305-314
• /
• 2018

강판 콘크리트 합성보는 강판, 콘크리트 및 2가지의 이질 재료를 결합시키는 전단 연결재로 구성되어 있다. 일반적으로 강판은 기존의 합성보에 용접하여 조립된다. 본 연구에서는 전단 연결재를 감소시키고, 작업성을 향상시키기 위해 SPC(Steel Plate Concrete Composite Beam) 보라 불리는 새로운 강판 콘크리트 합성보를 개발했다. SPC 보는 전단 연결재 없이 절곡된 강판과 콘크리트로 구성된다. 절곡된 강판은 용접 대신 고강도 볼트로 조립된다. 또한, 건설 현장에서 작업성을 향상시키기 위해 슬래브와 접합부에 모자 모양의 Cap이 부착된다. 변위 제어 모드에서 2점 가력 실험을 수행하였고, 시편의 휨강도를 계산하기 위해 소성 응력 분포법과 변형률 적합법을 사용하였다. 시험 결과에 따르면 새로운 SPC 보의 휨 강도는 완전 합성보 강도의 76 %의 값이 나왔다. Cap은 스터드와 부속 철물의 역할을 수행한다. 또한, Cap의 간격 제어를 통해 합성율의 증가가 가능하고, SPC 합성보의 합성율을 고려할 경우 변형률 적합법을 통해 SPC 합성보의 휨 성능 평가가 가능하다.

• 한국산학기술학회논문지
• /
• 제19권6호
• /
• pp.126-136
• /
• 2018

강판 콘크리트 합성보는 2개의 이질 재료를 결합하기 위해 강판, 콘크리트 및 전단 연결재로 구성된다. 일반적으로 강판은 기존의 합성보에 용접하여 조립된다. 본 연구에서는 전단 강도를 줄이고 작업성을 향상시키기 위해 SPC Beam이라 불리는 새로운 강판 콘크리트 합성 보(Beam)를 개발했다. SPC 보는 전단 연결재 없이 절곡된 강판과 콘크리트로 구성된다. 절곡된 강판은 용접 대신 고강도 볼트로 조립된다. 현장 건설의 작업성을 향상시키기 위해 슬래브와 접합부에 모자 모양의 Cap이 부착되어 있다. 변위 제어 모드에서 2점 가력의 단조 하중 시험을 수행했다. 정모멘트와 부모멘트에 대한 시편의 굽힘강도는 소성 응력 분포법에 의해 계산되었다. 수행한 시험 결과에 따르면 새로운 SPC 보의 휨 강도는 완전 합성보의 강도의 80% 이다. Cap의 간격을 조절하여 합성율의 증가가 가능했다. 본 연구에서는 정 부모멘트 역에서의 대표 형상을 대상으로 하였기 때문에, 단면 형상과 Cap을 변수로 추가적인 실험과 해석을 통해 SPC Beam의 성능 검증이 수행될 것이다.

• Steel and Composite Structures
• /
• 제34권1호
• /
• pp.91-105
• /
• 2020

Steel-concrete composite beam with profiled steel sheet has gained its popularity in the last two decades. Due to the ageing of these structures, retrofitting in terms of flexural strength is necessary to ensure that the aged structures can carry the increased traffic load throughout their design life. The steel ribs, which presented in the profiled steel deck, limit the use of shear connectors. This leads to a poor degree of composite action between the concrete slab and steel beam compared to the solid slab situation. As a result, the shear connectors that connects the slab and beam will be subjected to higher shear stress which may also require strengthening to increase the load carrying capacity of an existing composite structure. While most of the available studies focus on the strengthening of longitudinal shear and flexural strength separately, the present work investigates the effect of both flexural and longitudinal shear strengthening of steel-concrete composite beam with composite slab in terms of failure modes, ultimate load carrying capacity, ductility, end-slip, strain profile and interface differential strain. The flexural strengthening was conducted using carbon fibre reinforced polymer (CFRP) or steel plate on the soffit of the steel I-beam, while longitudinal shear capacity was enhanced using post-installed high strength bolts. Moreover, a combination of both the longitudinal shear and flexural strengthening techniques was also implemented (hybrid strengthening). It is concluded that hybrid strengthening improved the ultimate load carrying capacity and reduce slip and interface differential strain that lead to improved composite action. However, hybrid strengthening resulted in brittle failure mode that decreased ductility of the beam.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
• /
• pp.493-498
• /
• 2003

The 3D nonlinear analysis for steel-concrete hybrid deck is carried out by utilizing 2D plane interface element. The effect of the slip occurred between steel and concrete can be modeled by this element. This analysis focuses on not only global behavior of steel-concrete hybrid deck but also local behaviors of members of it such as lower steel plate, I-beam, and concrete which are varied by slip modulus. In this analysis, it was founded that the limit slip modulus could classify the states of steel-concrete hybrid deck into three parts such as full-composite, partial-composite, and non-composite, considering the behavior of lower steel plate, I-beam, and concrete at the mid span and the support as well as the yield load and ultimate load of it.

• 한국공간구조학회논문집
• /
• 제17권3호
• /
• pp.99-105
• /
• 2017

The SLIM AU composite beam consists of U-shaped steel plate, A-shaped steel cap and infilled concrete. The bottom steel plate acts as tension bars, and the top steel cap takes roles of shear connector and compression bars in the conventional reinforced concrete section. In this paper the shear strength of this composite beam with closed steel section has been evaluated through the concentrated loading shear experiments. Test results under the symmetrical and asymmetrical loading conditions were compared with the predicted values based on the KBC 2016. The composite beam showed the greater shear strength capacities than those of the theoretical evaluation.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
• /
• pp.173-176
• /
• 2003

Progressive failure analysis of steel composite double T-beam is performed to investigate the mechanical effects of steel composite fabricated in the webs of double-T beam to replace concrete placing forms. The analysis is based on nonlinear finite element scheme considering material nonlinearities of concrete, reinforcing bar and PS steel. Four-parameter strength envelope defines the hardening and softening phenomena of concrete with consideration of the various levels of confining pressures. Rankine maximum strength criterion defines the elasto-plasticity of PS steel and reinforcing bar, and Von Mises $J_2$ failure criterion for steel plate which wraps the concrete webs of double T-beam. A 6m long two-span steel composite double T-beam is analyzed and compared with the experimental results.

• Steel and Composite Structures
• /
• 제19권3호
• /
• pp.735-757
• /
• 2015

Composite bonding steel plate (CBSP) is a newly developed type of structure strengthened technique applicable to the existing RC beam. This composite structure is applicable to strengthening the existing beam bearing high load. The strengthened beam consists of two layers of epoxy bonding prestressed steel plates and the RC beam sandwiched in between. The bonding enclosed and prestressed U-shaped steel jackets are applied at the beam sides. This technique is adopted in case of structures with high longitudinal reinforcing bar ratio and impracticable unloading. The prestress can be generated on the strengthening steel plates and jackets by using the CBSP technique before loading. The test results of full-scale CBSP strengthened beams show that the strength and stiffness are enhanced without reduction of their ductility. It is demonstrated that the strain hysteresis effect can be effectively overcome after prestressing on the steel plates by using such technique. The applied plates and jackets can jointly behave together with the existing beam under the action of epoxy bonding and the mechanical anchorage of the steel jackets. The simplified formulas are proposed to calculate the prestress and the ultimate capacities of strengthened beams. The accuracy of formulas was verified with the experimental results.

• Steel and Composite Structures
• /
• 제11권4호
• /
• pp.291-305
• /
• 2011

The new structure consisting of continuous compound spiral hoop reinforced concrete (CCSHRC)column and steel concrete composite (SCC) beam has both the advantages of steel structures and concrete structures. Two types of beam-to-column connections applied in this structural system are presented in this paper. The connection details are as follows: the main bars in beam concrete pass through the core zone for both types of connections. For connecting bar connection, the steel I-beam webs are connected by bolts to a steel plate passing through the joint while the top and bottom flanges of the beams are connected by four straight and two X-shaped bars. For bolted end-plate connection, the steel I-beam webs are connected by stiffened extended end-plates and eight long shank bolts passing through the core zone. In order to study the seismic behaviour and failure mechanisms of the connections, quasi-static tests were conducted on both types of full-scale connection subassemblies and core zone specimens. The load-drift hysteresis loops show a plateau for the connecting bar connection while they are excellent plump for bolted end-plate connection. The shear capacity formulas of both types of connections are presented and the values calculated by the formula agree well with the test results.