• Structural Engineering and Mechanics
• /
• 제15권2호
• /
• pp.181-198
• /
• 2003

Six large scale models of conventionally reinforced concrete coupling beams with span/depth ratios ranging from 1.17 to 2.00 were tested under monotonically applied shear loads to study their nonlinear behavior using a newly developed test method that maintained equal rotations at the two ends of the coupling beam specimen and allowed for local deformations at the beam-wall joints. By conducting the tests under displacement control, the post-peak behavior and complete load-deflection curves of the coupling beams were obtained for investigation. It was found that after the appearance of flexural and shear cracks, a deep coupling beam would gradually transform itself from an ordinary beam to a truss composed of diagonal concrete struts and longitudinal and transverse steel reinforcement bars. Moreover, in a deep coupling beam, the local deformations at the beam-wall joints could contribute significantly (up to the order of 50%) to the total deflection of the coupling beam, especially at the post-peak stage. Finally, although a coupling beam failing in shear would have a relatively low ductility ratio of only 5 or even lower, a coupling beam failing in flexure could have a relatively high ductility ratio of 10 or higher.

• 한국전산구조공학회논문집
• /
• 제31권6호
• /
• pp.293-299
• /
• 2018

초고층 건물의 횡변위 제어를 위하여 사용되는 아웃리거를 기존의 철골 트러스 대신에 철근콘크리트 벽체로 대체할 수 있다. 철근콘크리트 아웃리거 벽체를 외부 기둥에 연결할 경우에는 축력뿐만 아니라 전단력과 모멘트가 외부 기둥에 유발될 수 있다. 본 연구에서는 아웃리거 벽체 외단부의 회전으로 인한 외부 기둥의 전단력을 수식으로 유도하고 그 값을 유한요소 해석 결과와 비교하였다. 유한요소해석에서는 층별 연결보의 효과와 전단벽과 아웃리거를 보와 평면응력요소로 모델링한 효과를 분석하였다. 층별 연결보의 효과는 거의 없었으며 평면응력요소는 보요소보다 더 큰 강성을 가진 것으로 해석되었다. 아웃리거 벽체의 외단부 회전으로 인한 외부기둥의 층간 회전각과 전단력은 허용값에 비하여 상당히 작은 값이 발생하였다. 따라서 초고층 건물에 철근콘크리트로 된 아웃리거 벽체를 적용할 경우에도 외부 기둥에 유발되는 전단력과 모멘트에 대하여 별도의 검토를 할 필요는 없을 것으로 판단된다.

• Structural Engineering and Mechanics
• /
• 제76권6호
• /
• pp.687-708
• /
• 2020

Openings in steel plate shear walls (SPSWs) are usually used for decorative designs, crossing locations of multiple utilities and/or structural objectives. However, earlier studies showed that generating an opening in an SPSW has a negative effect on the cyclic performance of the SPSW. Therefore, this study proposes tripling or doubling the steel-sheet-plate (SSP) layer and stiffening the opening of the SPSW to provide a solution to undesirable opening effects, improve the SPSW performance and provide the infill option of potential strengthening measures after the construction stage. The study aims to investigate the impact of SSP doubling with a stiffened opening on the cyclic behaviour, expand the essential data required by structural designers and quantify the SPSW performance factors. Validated numerical models were adopted to identify the influence of the chosen parameters on the cyclic capacity, energy dissipation, ductility, seismic performance factors (SPF) and stiffness of the suggested method. A finite Element (FE) analysis was performed via Abaqus/CAE software on half-scale single-story models of SPSWs exposed to cyclic loading. The key parameters included the number of SSP layers, the opening size ratios corresponding to the net width of the SSP, and the opening shape. The findings showed that the proposed assembly method found a negligible influence in the shear capacity with opening sizes of 10, 15, 20%. However, a deterioration in the wall strength was observed for openings with sizes of 25% and 30%. The circular opening is preferable compared with the square opening. Moreover, for all the models, the average value of the obtained ductility did not show substantial changes and the ultimate shear resistance was achieved after reaching a drift ratio of 4.36%. Additionally, the equivalent sectional area of the SSP in the twin and triple configuration of the SPSWs demonstrated approximately similar results. Compared with the single SSP layer, the proposed configuration of the twin SSP layer with a stiffened opening suggest to more sufficiency create SSP openings in the SPSW compared to that of other configurations. Finally, a tabular SPF quantification is exhibited for SPSWs with openings.

• 콘크리트학회논문집
• /
• 제17권6호
• /
• pp.1001-1009
• /
• 2005

고층 건물의 구조계획에서 벽체의 유용성은 오래전부터 인식되어 왔다. 구조물에서 적절한 위치에 벽체를 배치하며, 벽체는 구조물에 작용하는 횡하중에 매우 효과적으로 저항할 수 있다. 특히 병렬 전단벽 시스템의 구조물의 횡력저항 시스템으로서 가장 선호되는 구조이고 이러한 구조는 커플링보에 의해 벽체가 연결되게 된다. 커플링보는 강도, 강성, 연성 및 에너지 소산능력이 충분한 부재이어야 한다. 이러한 요구들을 만족시키기 위해 FBP를 적용한 철골 커플링보를 제안한다. FBP의 적용 여부를 변수로 하여 총 2개의 시험체를 계획하고 실험을 실시하였다. 이러한 실험 연구를 통하여 FBP를 적용한 철골 커플링보의 장점에 대해 서술하였고, 파괴모드를 제안하였다.

• Computers and Concrete
• /
• 제20권3호
• /
• pp.351-360
• /
• 2017

This paper presents an efficient membrane finite element for the cyclic inelastic response analysis of RC structures under complex plane stress states including shear. The model strikes a balance between accuracy and numerical efficiency to meet the challenge of shear wall simulations in earthquake engineering practice. The concrete material model at the integration points of the finite element is based on damage plasticity with two damage parameters. All reinforcing bars with the same orientation are represented by an embedded orthotropic steel layer based on uniaxial stress-strain relation, so that the dowel and bond-slip effect of the reinforcing steel are presently neglected in the interest of computational efficiency. The model is validated with significant experimental results of the cyclic response of RC panels with uniform stress states.

• Earthquakes and Structures
• /
• 제22권5호
• /
• pp.461-473
• /
• 2022

Energy-saving block and invisible multiribbed frame composite wall (EBIMFCW) is an important shear wall, which is composed of energy-saving blocks, steel bars and concrete. This paper conducted seismic performance tests on six 1/2-scale EBIMFCW specimens, analyzed their failure process under horizontal reciprocating load, and studied the effect of axial compression ratio on the wall's hysteresis curve and skeleton curve, ductility, energy dissipation capacity, stiffness degradation, bearing capacity degradation. A formula for calculating the peak bearing capacity of such walls was proposed. Results showed that the EBIMFCW had experienced a long time deformation from cracking to failure and exhibited signs of failure. The three seismic fortification lines of the energy-saving block, internal multiribbed frame, and outer multiribbed frame sequentially played important roles. With the increase in axial compression ratio, the peak bearing capacity and ductility of the wall increased, whereas the initial stiffness decreased. The change in axial compression ratio had a small effect on the energy dissipation capacity of the wall. In the early stage of loading, the influence of axial compression ratio on wall stiffness and strength degradation was unremarkable. In the later stage of loading, the stiffness and strength degradation of walls with high axial compression ratio were low. The displacement ductility coefficients of the wall under vertical pressure were more than 3.0 indicating that this wall type has good deformation ability. The limit values of elastic displacement angle under weak earthquake and elastic-plastic displacement angle under strong earthquake of the EBIMFCW were1/800 and 1/80, respectively.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 추계학술대회논문집
• /
• pp.452-458
• /
• 2007

The vertical extension of a building in general remodeling process increases both gravity and seismic loads by simply adding masses to the building. In this study, a vertical extension structural module (VESM) is proposed for enhancing seismic performance of the existing buildings by utilizing the story-increased parts. The proposed VESM is composed of steel column, steel beam, and beam-end rotational damper. The steel columns are connected to the shear walls and transfer the wall rotation in out-of plane to the steel beam, and then the beam-end rotational damper dissipates the earthquake-induced energy. Numerical analysis result from a cantilever beam of which end-rotation is restricted by rotational damper indicates that the displacement, base shear, and base overturning moment of the existing structures showing cantilever behavior can be significantly reduced by using the proposed method. Also, it is observed that friction-type rotational damper is effective than viscous one.

• 한국소음진동공학회논문집
• /
• 제18권6호
• /
• pp.589-597
• /
• 2008

The vertical extension of a building in general remodeling process increases both gravity and seismic loads by simply adding masses to the building. In this study, a vertical extension structural module(VESM) is proposed for enhancing seismic performance of the existing buildings by utilizing the story-increased parts. The proposed VESM is composed of steel column, steel beam, and beam-end rotational damper. The steel columns are connected to the shear walls and transfer the wall rotation in out-of plane to the steel beam, and then the beam-end rotational damper dissipates the earthquake-induced energy. Numerical analysis result from a cantilever beam of which end-rotation is restricted by rotational damper indicates that the displacement, base shear, and base overturning moment of the existing structures showing cantilever behavior can be significantly reduced by using the proposed method. Also, it is observed that friction-type rotational damper is effective than viscous one.

• Steel and Composite Structures
• /
• 제36권5호
• /
• pp.507-519
• /
• 2020

Double skin composite walls are increasingly popular and have been applied to many safety-related facilities. They come from the concept of composite slabs. Conventional connectors such as shear studs and binding bars were used in previous studies to act as the internal mechanical connectors to lock the external steel faceplates to the concrete core. However, the restraint effects of these connectors were sometimes not strong enough. In this research, a recently proposed unique type of steel truss was employed along the wall height to enhance the composite action between the two materials. Concrete-filled tube columns were used as the boundary elements. Due to the existence of boundary columns, the restraints of steel faceplates to the concrete differ significantly for the walls with different widths. Therefore, there is a need to explore the effect of height-to-width ratio on the structural behavior of the wall. In the test program, three specimens were designed with the height of 3000 mm, the thickness of 150 mm, and different widths, to simulate the real walls in practice. Axial compression was applied by two actuators on the tested walls. The axial behavior of the walls was evaluated based on the analysis of test results. The influences of height-to-width ratio on structural performance were evaluated. Finally, discussion was made on code-based design.

• 한국공간구조학회논문집
• /
• 제17권4호
• /
• pp.77-84
• /
• 2017

As an alternative to coupling beam in shear wall system, application of the damper which can dissipate energy is increasing. In this study, lintel beam type steel damper which is simple to construct and change depending on design load was proposed. Cyclic loading test was conducted to compare reinforced concrete coupling beam and lintel beam type steel damper. The test results showed that lintel beam type steel damper has higher initial stiffness and energy dissipation capacity than reinforced concrete coupling beam.