• 한국지진공학회논문집
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• 제23권5호
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• pp.249-259
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• 2019

To study the seismic resistance of the shear capacity of the RC beam-column joints of two-story and four-story RC buildings, sample buildings are designed with ordinary moment resisting frame. For the shear capacity of joints, the equations of FEMA 356 and NZ seismic assessment are selected and compared. For comparison, one group of buildings is designed only for gravity loads and the other group is designed for seismic and gravity loads. For 16 cases of the designed buildings, seismic performance point is evaluated through push-over analysis and the capacity of joint shear strength is checked. Not only for the gravity designed buildings but also for seismic designed buildings, the demand of joint shear is exceeding the capacity at exterior joints. However, for interior joint, the demand of joint shear exceeds the capacity only for one case. At exterior joints, the axial load stress ratio is lower than 0.21 for gravity designed buildings and 0.13 for seismic designed buildings.

• Advances in concrete construction
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• 제9권5호
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• pp.503-510
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• 2020

Concrete dams are important structures due to retaining amount of water on their reservoir. So such kind of structures have to be designed against static and dynamic loads. Especially considering on critical importance against blasting threats and environmental safety, dams have to be examined according to the blast loads. This paper aims to investigate structural response of concrete gravity dams under blast loads. For the purpose Sarıyar Concrete Gravity Dam in Turkey is selected for numerical application with its 85 m of reservoir height (H), 255 m of reservoir length (3H), 72 m of bottom and 7 m of top widths. In the study, firstly 3D finite element model of the dam is constituted using ANSYS Workbench software considering dam-reservoir-foundation interaction and a hydrostatic analysis is performed without blast loads. Then, nearly 13 tons TNT explosive are considered 20 m away from downstream of the dam and this is modeled using ANSYS AUTODYN software. After that explicit analyses are performed through 40 milliseconds. Lastly peak pressures obtained from analyses are compared to empirical equations in the literature and UFC 3-340-02 standard which provide unified facilities criteria for structures to resist the effects of accidental explosions. Also analyses' results such as displacements, stresses and strains obtained from both hydrostatic and blasting analysis models are compared to each other. It is highlighted from the study that blasting analysis model has more effective than the only hydrostatic analysis model. So it is highlighted from the study that the design of dams should be included the blast loads.

• 한국지진공학회논문집
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• 제6권3호
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• pp.63-71
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• 2002

중력하중에 대하여서만 설계되고 내진에 대하여 설계되지 않은 6층 미만의 RC 골조를 대상으로 내진 저항력에 대한 추정식을 유도하였다. 추정식의 산정을 위하여 기둥 소성 힌지 붕괴기구와 보 소성 힌지 붕괴기구의 2가지 경우를 가정하여 이론식을 유도하였으며, 이를 4층 및 3층 건물의 push-over해석과 비교하였다. 연구 결과로, 중력 하중에 대하여서만 설계된 구조물의 내진 저항력은 bay수의 증가와 크게 관계가 없으며 저층일수록 증가하는 기존의 연구 결과와 잘 일치함을 알 수 있었다. 설계시 기둥의 철근 강도와 철근비가 증가할수록 내진 저항력이 증가함을 알 수 있었다. 또한 스팬의 길이보다는 기둥 춤의 크기가 내진저항력에 더 많은 영향을 미침을 알 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.1155-1160
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• 2001

The seismic design regulations have not been applied to low-rised buildings which are less than 6 stories. To evaluate the seismic strength of the low-rised building which is designed only for gravity, a theoretical and numerical analysis are peformed. In theoretical analysis, column hinge sway mechanism is assumed. For the numerical, push-over analysis is executed for 3 and 4 storied buildings. From the evaluations, the minimum base shear is found to be 0.1 g

• 한국지진공학회논문집
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• 제24권1호
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• pp.39-47
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• 2020

Lightly reinforced concrete (RC) moment frames may suffer significant damage during large earthquake events. Most buildings with RC moment frames were designed without considering seismic loads. The load-displacement response of gravity load designed frames could be altered by masonry infill walls. The objective of this study is to investigate the load-displacement response of gravity load designed frames with masonry infill walls. For this purpose, three-story gravity load designed frames with masonry infill walls were considered. The masonry infilled RC frames demonstrated larger lateral strength and stiffness than bare RC frames, whereas their drift capacity was less than that of bare frames. A specimen with a partial-height infill wall showed the least drift capacity and energy dissipation capacity. This specimen failed in shear, whereas other specimens experienced a relatively ductile failure mode (flexure-shear failure).

• 한국지진공학회논문집
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• 제14권3호
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• pp.31-38
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• 2010

본 연구에서는 기둥을 관통하는 슬래브 하부 철근이 중력하중만으로 설계된 포스트텐션 플랫플레이트 골조의 내진성능에 미치는 영향을 평가하였다. 중 약진 지역에서 건물은 흔히 중력하중만을 고려하여 설계되고 있다. 본 연구에서는 중력하중으로 설계된 PT 플랫플레이트 골조의 내진성능에 집중되고 있다. 이를 위하여, 3,6,9층 PT 플랫플레이트 골조는 중력하중만으로 설계하였다. 철근콘크리트 플랫플레이트 골조에서는 취성적인 붕괴를 예방하기 위해서는 기둥을 관통하는 연속된 슬래브 하부철근이 위치하여야 한다. 그러나 PT 플랫플레이트 골조에서는 슬래브 하부 철근에 대해 ACI 318-05에서는 특별한 언급이 없기 때문에 흔히 생략하고 있다. 본 연구는 대산건물을 비선형 시간이력해석 으로 골조 모델의 내진성능에 대해 평가한다. 비선형 시간이력해석은 6개의 지진과 2개의 다른 위험수준 (475, 2475년 주기), 3개의 다른 지역 (보스턴, 시애틀, LA)을 사용하였다. 해석모델은 PT슬래브-기둥 접합부의 파괴 메카니즘과 비선형 거동을 살펴보기 위해 개발되었다. 본 연구는 중력하중으로 설계된 PT 플랫플레이트 골조가 몇몇 내진저항 능력을 보여주고 있다. 또한, PT 플랫플레이트 골조의 내진성능은 기둥을 관통하는 슬래브 하부철근이 위치할 때 눈에 띄게 향상되었다.

• 콘크리트학회논문집
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• 제20권1호
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• pp.35-41
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• 2008

플랫플레이트 시스템은 주로 전단벽과 가새 골조와 같은 횡력저항 시스템과 함께 중력저항 시스템으로 사용된다. 따라서 지진과 같은 횡하중이 작용할 때, 중력저항 시스템은 중력하중에 대한 전달 능력을 유지하면서 일체로 연결된 횡력저항 시스템의횡변위를 견딜 수 있어야 한다. 또한 플랫플레이트 시스템은 지진에 대한 특별 상세조건에 만족하면 중간 모멘트 골조로써 횡력저항 시스템으로도 사용할 수 있다. 그러나 횡하중이 작용하는 경우 플랫플레이트 시스템은 횡변위와 불균형모멘트로 인한 뚫림 전단의 위험성은 더욱 커지게 된다. 따라서 플랫플레이트 시스템을 중력 저항 또는 횡력 저항 시스템으로 설계하는 모든 경우에 중력하중뿐만 아니라 횡하중하의 설계 내력 (모멘트와 전단력)과 변위 등의 합리적인 예측은 매우 중요하다. ACI 318 (2005)에서는 중력하중에 대한 해석시 직접설계법과 등가골조법을 제시하고 있으며, 횡하중에 대한 해석으로 유한요소법, 유효보폭법, 등가골조법을 허용한다. 이러한 해석법은 각각 장단점을 갖고 있으며, 매우 광범위한 해석 결과를 보인다. 따라서 구조 설계자들은 적절한 해석법의 선택과 해석 결과를 분석하는데 어려움을 갖는다. 본 연구의 목적은 플랫플레이트 해석법에 대한 구조 설계자들이 적절한 해석법을 선택할 수 있도록 하고, 횡하중에 대한 해석 방법으로 수정된 등가골조법의 실용성을 검증하고자 하였다. 이를 위하여 중력하중과 횡하중을 받는 7층의 플랫플레이트 구조물에 대한 내부력과 횡변위를 대상으로 유한요소해석을 수행하고 각 골조해석법의 결과를 비교하였다. 또한 각 골조해석법의 정확성은 기존 플랫플레이트 슬래브 구조물의 실험 결과와 비교하여 검증하였다.

• Computers and Concrete
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• 제31권1호
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• pp.23-32
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• 2023

Reinforced concrete flat slab (RCFS) with columns is a standard gravity floor system for tall buildings in North America. Typically, RCFS-column connections are designed to resist gravity loads, and their contribution to resisting seismic forces is ignored. However, past experimental research has shown that RCFS-column connections have some strength and ductility, which may not be ignored. Advanced numerical models have been developed in the past to determine the nonlinear cyclic behavior of RCFS-column connections. However, these models are either too complicated for nonlinear dynamic analysis of an entire building or not developed to model the behavior of modern RCFS-column connections. This paper proposes a new nonlinear model suitable for modern RCFS-column connections. The numerical model is verified using experimental data of specimens with various material and reinforcement properties. A 40-story RC shear wall building was designed and analyzed to investigate the influence of RCFS on the global response of tall concrete buildings. The seismic responses of the building with and without the RCFS were modelled and compared. The results show that the modelling of RCFS has a significant impact on the inter-story drifts and force demands on both the seismic force-resisting and gravity elements.

• Wind and Structures
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• 제12권5호
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• pp.425-439
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• 2009

The expediency of revising universal rules for the combination of gravity and lateral actions of wind force-resisting steel structures recommended by the Standards EN 1990 and ASCE/SEI 7-05 is discussed. Extreme wind forces, gravity actions and their combinations for the limit state design of structures are considered. The effect of statistical uncertainties of extreme wind pressure and steel yield strength on the structural safety of beam-column joints of wind force-resisting multistory steel frames designed by the partial factor design (PFD) and the load and resistance factor design (LRFD) methods is demonstrated. The limit state criterion and the performance process of steel frame joints are presented and considered. Their long-term survival probability analysis is based on the unsophisticated method of transformed conditional probabilities. A numerical example illustrates some discrepancies in international design standards and the necessity to revise the rule of universal combinations of loads in wind and structural engineering.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.138-141
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• 2006

Shear wall-frame system is one of the most, if not the most, popular system for resisting lateral loads. The core is the primary lateral load-resisting systems, the perimeter frame is designed for gravity loads, and the connection between perimeter frame and core is generally a shear connection. Specially, single plate shear connection have gained considerable popularity in recent years due to their ease of fabrication and erection. Single plate shear connection should be designed to satisfy the dual criteria of shear strength and rotational ductility. An experimental program was undertaken to evaluate seismic behavior of single plate shear connection. The main test variable is the reinforcing detail of connection. Through the experimental program, the cyclic behavior of typical and reinforcing single plate shear connection was established.