• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
• /
• pp.117-122
• /
• 2002

Flat Plate structures subjected to lateral load are susceptible to the brittle failure, therefore deformability of plate-column connections should be ensured to resist against earthquake. However, according to previous study, existing experiments overestimate the deformability of connections and current design provision do not accurately explains them. In the present study, parametric study using nonlinear finite element analysis was performed. Based on the numerical results, seismic design method considering the deformability of connections was developed.

• 한국강구조학회 논문집
• /
• 제16권2호통권69호
• /
• pp.247-255
• /
• 2004

본 실험프로그램은 슬래브가 있는 합성보의 내진성능향상을 위해 기존 모멘트접합부의 내진보강 방법을 개발을 목적으로 수행하였다. 반복하중을 통해 5개의 실대형 합성실험체에 대한 실험을 수행하였다. 각형강관기둥과 H형강보로 이루어진 기존의 다이아프램접합부가 RBS 또는 개량수평스티프너를 통해서 하부플랜지에만 내진 보강되었다. 제안한 보강접합부의 효율성을 조사하였다. 실험결과 하부플랜지에만 RBS를 적용한 접합부는 부족한 변형성능을 나타냈지만, 개량스티프너를 적용한 합성보 접합부는 내진성능을 향상시켰다.

• Structural Engineering and Mechanics
• /
• 제24권4호
• /
• pp.463-478
• /
• 2006

The design of structural frameworks for buildings is constantly evolving and is dependent on regional issues such as loading and constructability. One of the most promising recent developments for low to medium rise construction in terms of efficiency of construction, robustness and aesthetic appearance utilises concrete-filled steel tubular sections as the columns in a moment-resisting frame. These are coupled to rigid or semi-rigid connections to composite steel-concrete beams. This paper includes the results of a pilot experimental programme leading towards the development of economical, reliable connections that are easily constructed for this type of frame. The connections must provide the requisite strength, stiffness and ductility to suit gravity loading conditions as well as gravity combined with the governing lateral wind or earthquake loading. The aim is to develop connections that are stiffer, less expensive and easier to construct than those in current use. A proposed fabricated T-stub connection is to be used to connect the beam flanges and the column. These T-stubs are connected to the column using "blind bolts" with extensions, allowing installation from the outside of the tube. In general, the use of the extensions results in a dramatic increase in the strength and stiffness of the T-stub to column connection in tension, since the load is shared between membrane action in the tube wall and the anchorage of the bolts through the extensions into the concrete.

• Steel and Composite Structures
• /
• 제32권1호
• /
• pp.79-90
• /
• 2019

This study introduces new connections that connect the beam to the column with slit dampers. Plastic deformations and damages concentrate on slit dampers. The slit dampers prevent plastic damages of column, beam, welds and panel zone and act as fuses. The slit dampers were prepared with IPE profiles that had some holes in the webs. In this paper, two experimental specimens were made. In first specimen (SDC1), just one slit damper connected the beam to the column and one IPE profile with no holes connected the bottom flange of the beam to the column. The second specimen (SDC2) had two similar dampers which connected the top and bottom flange of the beam to the column. Cyclic loading was applied on Specimens. The cyclic displacements conditions continued until 0.06 radian rotation of connection. The experimental observations showed that the bending moment of specimen SDC2 increased until 0.04 story drift. In specimen SDC1, the bending moment decreases after 0.03 story drift. Test results indicate the high performance of the proposed connection. Based on the results, the specimen with two slit damper (SDC2) has higher seismic performance and dissipates more energy in loading process than specimen SDC1. Theoretical formulas were extended for the proposed connections. Numerical studies have been done by ABAQUS software. The theoretical and numerical results had good agreements with the experimental data. Based on the experimental and numerical investigations, the high ductility of connection is obtained from plastic damages of slit dampers. The most flexural moment of specimen SDC1 occurred at 3% story drift and this value was 1.4 times the plastic moment of the beam section. This parameter for SDC2 was 1.73 times the plastic moment of the beam section and occurred at 4% story drift. The dissipated energy ratio of SDC2 to SDC1 is equal to 1.51.

• 한국강구조학회 논문집
• /
• 제12권5호통권48호
• /
• pp.559-568
• /
• 2000

본 논문에서는 용접 수평헌치로 보강된 내진 철골모멘트접합부를 간단히 해석적으로 모형화하는 새로운 방안을 제시하였다. 1994년 노스리지 및 1995년 효고현 남부 지진피해 이후 철골모멘트접합부의 새로운 내진상세가 다양하게 제시되어 왔다. 이 가운데 보의 하부를 헌치로서 보강하는 방안도 유망한 대안의 하나로 평가되고 있다. 삼각헌치 대신 수평헌치를 도입하면 보강작업이 용이하고 경제적으로도 유리하나 아직 응력전달 메카니즘이 규명되지 않고 있어서 정립된 설계방안이 존재하지 않는다. 본 연구에서는 보와 헌치의 상호작용 및 변형의 적합조건을 고려하여 이 문제의 해결방안을 제시하였다. 본 연구의 방안에 의해 설계에 필요한 보-헌치의 상호작용력 및 보와 헌치 플랜지 용접부의 휨응력도를 만족스럽게 예측할 수 있다.

• Structural Engineering and Mechanics
• /
• 제39권2호
• /
• pp.241-266
• /
• 2011

The Self Compacting Concrete, SCC is the new generation type of concrete which is not needed to be compacted by vibrator and it will be compacted by its own weight. Since SCC is a new innovation and also the high strength self compacting concrete, HSSCC behavior is like a brittle material, therefore, understanding the strength effect on the serviceability performance of reinforced self compacting concretes is critical. For this aim, first the normal and high strength self compacting concrete, NSSCC and HSSCC was designed. Then, the serviceability performance of reinforced connections consisting of NSSCC and HSSCC were investigated. Twelve reinforced concrete connections (L = 3 m, b = 0.15 m, h = 0.3 m) were simulated, by this concretes, the maximum and minimum reinforcement ratios ${\rho}$ and ${\rho}^{\prime}$ (percentage of tensile and compressive steel reinforcement) are in accordance with the provision of the ACI-05 for conventional RC structures. This study was limited to the case of bending without axial load, utilizing simple connections loaded at mid span through a stub (b = 0.15 m, h = 0.3 m, L = 0.3 m) to simulate a beam-column connection. During the test, concrete and steel strains, deflections and crack widths were measured at different locations along each member. Based on the experimental readings and observations, the cracked moment of inertia ($I_{cr}$) of members was determined and the results were compared with some selective theoretical methods. Also, the flexural crack widths of the members were measured and the applicability for conventional vibrated concrete, as for ACI, BS and CSA code, was verified for SCCs members tested. A comparison between two Codes (ACI and CSA) for the theoretical values cracking moment is indicate that, irrespective of the concrete strength, for the specimens reported, the prediction values of two codes are almost equale. The experimental cracked moment of inertia $(I_{cr})_{\exp}$ is lower than its theoretical $(I_{cr})_{th}$ values, and therefore theoretically it is overestimated. Also, a general conclusion is that, by increasing the percentage of ${\rho}$, the value of $I_{cr}$ is increased.

• 한국강구조학회 논문집
• /
• 제29권4호
• /
• pp.303-310
• /
• 2017

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.

• 한국지진공학회논문집
• /
• 제3권4호
• /
• pp.61-70
• /
• 1999

1994년 Northridge 지진과 1995년 Kobe 지진에서 많은 철골구조물의 보-기둥 접합부에 발생한 규열은 내진성능이 우수한 것으로 알려진 모멘트 저항 철골골조의 내진성능 개선에 대한 연구필요성을 제시하였다 일반적으로 모멘트 저항 골조가 강한 지진을 받을 때 보-기둥 접합부는 강도의 저하없이 소성 회전변형능력이 0.015이면 만족할 수 있다고 한다. 본 연구의 목적은 강한 지진하중에서도 철골구조의 보-기둥 접합부에서 용접부의 균열이 방지되고 연성적으로 충분한 에너지를 흡수하고 소산할 수 있는 접합부의 형태를 제안하고 그 거동을 조사하는 것이다 본 연구에서는 접합부의 형태를 제안하였으며 실험을 통하여 그 거동을 분석하였다 제안된 접합부 시험체에 대한 실험결과는 용접부에 균열이 발생하지 않았으며충분한 변형능력을 나타냈다.

• 한국강구조학회 논문집
• /
• 제23권5호
• /
• pp.595-606
• /
• 2011

본 연구는 기둥-보 접합부의 강성에 따른 철골 모멘트 골조의 동적특성의 차이를 파악하는데 목적이 있다. 6층의 철골 모멘트 골조를 설계하였으며, 접합부는 DWA (Double Web-Angle Connection), TSW (Top-and Seat-Angle Connection with Double Web-Angle), FEMA(SAC-Test Summary No.28, Specimen ID : UCSD-6) 접합부를 사용하였고, 완전강접합부의 동적거동특성과 상호 비교 검토하였다. 반강접 접합부의 회전강성은 Chen 과 Kishi 에 의해 제안된 3매개변수파워모델을 사용하여 구하였다. 접합부의 회전 강성을 보의 강성으로 나누어 상대강성으로 정의하여 사용하였다. 모든 골조에 대하여 비선형 정적해석(push over analysis), 반복하중 해석 및 시간이력해석을 수행하였다. 각 접합부의 강성에 따른 내진거동은 층간변위, 소성힌지 및 이력 에너지 분배의 항목별로 비교 분석하였다.

• Steel and Composite Structures
• /
• 제50권6호
• /
• pp.627-641
• /
• 2024

This paper presents an experimental and numerical study to investigate the behavior of the precast segmental concrete beams (PSCBs) utilizing high-strength concrete (HSC) connected in the zone of the maximum bending moment using steel extended endplate connections (EECs). The experimental study consisted of five beams as follows: The first beam was the control beam for comparison, which was an unconnected one-piece beam made of HSC. The other four other beams consisted of two identical pieces of precast concrete. An important point to be noted is that at the end of each piece, a steel plate was used with a thickness of 10 mm. Moreover, this steel plate was welded to the lower and upper reinforcing bars of the beam. Furthermore, the steel plate was made to connect the two pieces using the technique of EECs. Several variables were taken in these four beams, whether from the shape of the connection or enhancing the behavior of the connection using the post-tensioning technique. EECs without stiffeners were used for some of the tested beams. The behavior of these connections was improved using stiffeners and shear bolts. To get accurate results, a comparison was made between the behaviors of the five beams. Another important point to be noted is that Abaqus and SAP2000 programs were used to investigate the behavior of PSCBs and to ensure the accuracy of the modeling process which showed a good agreement with the experimental results. Additionally, the simplified modeling using SAP2000 was able to model the nonlinear behavior of PSCBs connected using steel EECs. It was found that the steel pre-tensioned bolted EECs, reinforced with steel stiffeners and shear anchors, could be used to connect the precast HSC segmental beams via the internal pre-stressing technique.