• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.95-102
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• 2017

This paper describes the experimental results for the structural performance of full-scale coupling beams with different reinforcement layout (diagonal and horizontal). For the reinforcements of the coupling beams, high-strength steel bars(SD500 and SD600) were used in order to improve workability and economic feasibility. The rigid steel frames and linked joints were used to maintain the clear span length (distance between both shear walls) of the coupling beam during the cyclic loading. Experimental results indicated that the diagonally reinforced coupling beam specimen could exhibit more ductile behavior compared to horizontally reinforced specimen. ACI318-14 code is applicable to design of coupling beam with diagonally reinforcement, however, that is overestimating the strength of horizontally reinforced coupling beam. It is remarkable that effective elastic stiffness values of both reinforcement details coupling beam significantly lees than ASCE 41-13.

• Journal of the Korea Concrete Institute
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• v.18 no.4 s.94
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• pp.497-506
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• 2006

The precast concrete beam-column connectors for the high-rise office buildings were investigated experimentally in this study. The specimens of general precast beam-column connector which is used in a domestic site, specimen of DDC(dywidag ductile connectors) of Germany, and specimen of DDC with post-tensioning and modified DDC with post-tensioning were constructed and tested to verify the safety. The DDC with and without post-tensioning showed reliable joint strength and ductility but failed in critical inclined shear crackings at the column. The modified one showed better behaviors in tests because they did not show critical column crackings at failure. The use of prestressing did not helpful significantly to increase the strength and ductility of connectors but helpful only to develop self-centering behavior for stability.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.441-450
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• 2010

This is a preliminary study on the development of precast beam-column joints for dry construction methodology. Precast beam column joints with thru-connectors (BCJ_TC) using high strength bars or PS strands were developed and their seismic performance including strength degradation, stiffness degradation and energy dissipation capacity was experimentally evaluated. Test results showed that compressive failures at the end blocks of PC beam members occurred dominantly while PC columns including panel zones were free from any damage. However, the connections confined with CFRP at the end block showed much improved seismic performance than that of the unconfined connections. Connections with neoprene pad fillers between beam and column interfaces were better than the other connections in all the seismic performances except initial stiffness. To improve the seismic performances of BCJ_TC, compressive strength of the concrete at the end block need to be increased to compensate for the additional compressive stresses due to unbonded connectors and deformation of connectors should be controlled respectively.

• Journal of the Korea Concrete Institute
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• v.29 no.1
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• pp.43-51
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• 2017

As per current seismic design codes, diagonally reinforced coupling beams are restricted to coupling beams having aspect ratio below 4. However, a grouped diagonally reinforcement detail makes distribution of steel bars in the beam much harder, furthermore it may result in poor construction quality. This paper describes the experimental results of concrete coupling beam reinforced with high-strength steel bars (SD500 & SD600 grades). In order to improve workability for fabricating coupling beams, a headed large diameter steel bar was used in this study. Two full-scale coupling beams were fabricated and tested with variables of reinforcement details and aspect ratio. To reflect real behavior characteristic of the beam coupling shear walls, a rigid steel frame system with linked joints was set on the reaction floor. As a test result, it was noted that cracking and yielding of reinforcement were initially progressed at the coupling beam-to-shear wall joint, and were progressed to the mid-span of the coupling beam, based on the steel strain and failure modes. It was found that the coupling beams have sufficient deformation capacity for drift ratio of shear wall corresponding to the design displacement in FEMA 450-1. In this study, the headed horizontal steel bar was also efficient for coupling beams to exhibit shear performance required by seismic design codes. For detailed design for coupling beam reinforced with high-strength steel, however, research about the effect of variable aspect ratios on the structural behavior of coupling beam is suggested.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.659-662
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• 2007

알고리즘의 설계에 있어서 주어진 연결망을 다른 연결망으로 임베딩하는 것은 알고리즘을 활용하는 중용한 방법중의 하나이다. 본 논문에서는 하이퍼큐브보다 망비용이 개선된 이븐 연결망과 오드 연결망 사이의 임베딩을 분석하고, 이븐 연결망이 이분할 연결망임을 보인다. 이븐 연결망을 오드 연결망에 연장율 2, 밀집율 1에 임베딩 가능함을 보이고, 오드 연결망을 이븐 연결망에 연장율 2, 밀집율 1에 임베딩 가능함을 보인다.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.667-670
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• 2007

알고리즘의 설계에 있어서 주어진 연결망을 다른 연결망으로 임베딩하는 것은 알고리즘을 활용하는 중용한 방법중의 하나이다. 본 논문에서는 하이퍼큐브보다 망비용이 개선된 이븐 연결망과 오드 연결망 사이의 임베딩을 분석하고, 이븐 연결망이 이분할 연결망임을 보인다. 이븐 연결망을 오드 연결망에 연장율 2, 밀집율 1에 임베딩 가능함을 보이고, 오드 연결망을 이븐 연결망에 연장율 2, 밀집율 1에 임베딩 가능함을 보인다.

• Journal of Korean Society of Steel Construction
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• v.30 no.1
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• pp.37-48
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• 2018

Cyclic loading tests for shear dominant hybrid steel link beams with circular web openings were performed to evaluate the seismic performance. Four half-scaled specimens with bolted connections were tested. The test parameter is a diameter of the web opening, i.e., shear strength ratio ($V_{pw}/V_p$) of the link beam and presence of top-seat angles. Using test results, adequate design shear strength of link beam was finally suggested. Test results showed that when the shear capacity is less than half of the plastic shear strength, seismic performance was improved due to mitigation of pinching under reversed cyclic inelastic deformations.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.219-227
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• 2013

This study analyzed the effect of performance connected-type foundations of behavior and the connected beams according to the characteristics into soft clay transmission tower foundation. For this purpose, the finite element analysis model was built and connected to the transmission tower foundation mat and the contact area of the connection beam by the percentage change in the behavior and resistance characteristics were analyzed and finite element verification of the validity of the analytical model was conducted using connected-type transmission tower results of the model experiments constructed, and effective connected-type transmission tower basis of the behavior of connected beams were selected by analyzing the effect due to the increase of the stiffness. In addition, weak analysis by connected beam self-bending moment distribution was conducted.

• Journal of Korean Society of Steel Construction
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• v.16 no.6 s.73
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• pp.833-846
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• 2004

This study presents a non-prismatic beam element for modeling the elastic behavior of steel beams, which have the post-Northridge connections in steel moment frames. The elastic stiffness matrix, including the shear effects for non-prismatic members with reduced beam section (RBS) connection, is in closed form. A simplified approach is also suggested, which uses a prismatic beam element to model beams with the RBS connection. This method can estimate quiteexactly the maximum story drift ratios of frames with the RBS connection. The effects of reduced beam section connection on the elastic stiffness of steel moment frames were investigated. The selection of a proper model to account for deformations at the joint might have a more important role in estimating the maximum story drift ratios of frames with better accuracy than the RBS cutouts.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.670-672
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• 2002

본 논문에서는 2개의 랩어라운드 에지를 갖는 m$\times$n(m 2, n$\geq$3, n 흘수) 그리드 그래프에서의 해밀톤 성질을 고려한다. 먼저 그리드 그래프가 해밀톤 연결된(hamiltonian-connected)그래프가 되기 위해 추가로 필요한 에지의 수가 2개 이상임을 보인다. 그리고 m$\times$n 그리드 그래프의 첫 행에 랩어라운드 에지를 추가한 그래프의 해밀톤 성질을 보인 후, m$\times$n 그리드 그래프의 첫 행과 마지막 행에 램어라운드 에지를 추가한 그래프가 해밀톤 연결된 그래프임을 보인다.