점토지반에 근입된 송전철탑 연결형 말뚝기초의 저항력증가계수

경두현,백규호,김대홍,이준환 한국지반공학회 2012 한국지반공학회논문집 Vol.28 No.8

Pile foundation for transmission tower constructed in weak ground can cause the damage of the tower due to the different settlement between the foundations. In Japan and USA, connected-pile foundations whose 4 foundations are connected each other by beams were used for transmission tower (TEPCO 1988, IEEE 2001). Resistance increasing factor for connected-pile foundation signify increasing amount of resistance due to the effect of connected-pile material. In this study, we performed model lateral load tests of connected-pile foundations for transmission tower and found the resistance increasing factors for connected-pile foundation. The tests were performed in silty clay, the resistance increasing factors were founded in various conditions that lateral load directions and height, the stiffness of beams in the connected-pile foundations were changed. The resistance increasing factors from our research were presented as a function of normal lateral loading height and normal stiffness of the connected-pile material. The resistances which were estimated from the resistance increasing factors were similar to measured values.

전기화학적 기법에 의한 미생물연료전지 내부저항 특성 파악 및 전력관리시스템 연계 전압 변화와 유기물 저감에 미치는 영향

장재경,박혜민,김태영,양윤석,여정진,강석원,백이,권진경,Jang, Jae Kyung,Park, Hyemin,Kim, Taeyoung,Yang, Yoonseok,Yeo, Jeongjin,Kang, Sukwon,Paek, Yee,Kwon, Jin Kyung 대한의용생체공학회 2018 의공학회지 Vol.39 No.5

The internal resistance of microbial fuel cell (MFC) using stainless steel skein for oxidizing electrode was investigated and the factors affecting the voltage generation were identified. We also investigated the effect of power management system (PMS) on the usability for MFC and the removal efficiency of organic pollutants. The performance of a stack microbial fuel cell connected with (PMS) or PMS+LED was analyzed by the voltage generation and organic matter reduction. The maximum power density of the unit cells was found to be $5.82W/m^3$ at $200{\Omega}$. The maximum current density was $47.53A/m^3$ without power overshoot even under $1{\Omega}$. The ohmic resistance ($R_s$) and the charge transfer resistance ($R_{ct}$) of the oxidation electrode using stainless steel skein electrode, were $0.56{\Omega}$ and $0.02{\Omega}$, respectively. However, the sum of internal resistance for reduction electrode using graphite felts loaded Pt/C catalyst was $6.64{\Omega}$. Also, in order to understand the internal resistance, the current interruption method was used by changing the external resistance as $50{\Omega}$, $300{\Omega}$, $5k{\Omega}$. It has been shown that the ohm resistance ($R_s$) decreased with the external resistance. In the case of a series-connected microbial fuel cell, the reversal phenomenon occurred even though two cells having the similar performance. However, the output of the PMS constantly remained for 20 hours even when voltage reversal occurred. Also the removal ability of organic pollutants (SCOD) was not reduced. As a result of this study, it was found that buffering effect for a certain period of time when the voltage reversal occurred during the operation of the microbial fuel cell did not have a serious effect on the energy loss or the operation of the microbial fuel cell.

Presenting a New Detail for the Rigid Connection Between I-Shaped Beam and Concrete-Filled Steel Tube Column with Stiffened Channel Link

Mehrzad Tahamouli Roudsari,Shohreh Sohaei,Morteza Torkaman,Seyed Ali Safaee,Salar Tahmasebi,Saleh Mohammadi,Mohammad Mehdi Ghiasvand 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.2

Connections play an important role in the response of steel moment resisting frames to seismic loading. Prequalified rigid connections are applicable to I-shaped or box columns. In I-shape beam to concrete-filled tube (CFT) column connections, continuity and doubler plates cannot be added to the column. Various details have been proposed to address this issue, many of which are not constructionally convenient to implement. The aim of this study is to present a simple and suitable detailing for I-shape beam to concrete-filled tube column connections. To that end, six full-scale experimental samples were built and subjected to cyclic quasi-static loading. In the samples, stiffened and un-stiffened channel links were used to connect the beam to the column. In each sample, the stiffeners were installed on a different position on the channel link. The results showed that compared to the connection in which the beam is directly connected to the column, using the stiffened channel link with stiffeners along the beam’s flange increases the strength and ductility of the connection by 12% and 72%, respectively. Considering their desirable performance and easy implementation, these connections can be considered as a suitable detailing for I-shape beam to CFT column connections in seismic regions.

다방향 접합철물 삽입형 기둥-기초 접합부 모멘트 저항성능평가

김건호,이상준 한국가구학회 2014 한국가구학회지 Vol.25 No.4

The purpose of this paper is to evaluate the moment resistance of glulam post-to-baseconnections by applying quasi-static cyclic loads. The connectors consisted of inserted platesand drifted pins according to the load direction. The connection types employed in this studywere total three including two unidirectional types (H, V) and the multi-directional type (M). The moment resistance of 8 mm-plate M-type is compared to 6 mm plate. Total four types ofPost-to-base connection are prepared and tested under pseudo-static reversed cyclic loading. Testresults showed that the yield moment of multi-directional connection is about 2 times higherthan that uni-directional connections. The ductility ratio of multi-directional connection determinedby EEEP was higher that that of uni-directional connection. It was becoming higheras the thickness of plate is increased. The Finite Element Analysis was conducted to estimatethe stress distribution behavior of tested connections. Results showed the failure of multi-directionaltype were caused by the split of pined hole and the shear failure of lifted part of post.

Parametric Study on Eff ect of Adding Stiff ener to Post-tensioned Steel Connection

M.R. Shiravand,A. Torabipour,S. Mahboubi 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.2

Beam-to-column connections with post-tensioned (PT) elements are used in steel moment-resisting frames to provide adequate stiff ness, strength, and ductility and to eliminate residual displacements under seismic loads. A steel PT connection has recently been developed with top and seat angles. In this connection, angles are used to dissipate energy under cyclic loading. This paper aims to investigate the infl uence of adding stiff eners to the top and seat angles on the cyclic responses of PT connections. To this end, a parametric study is performed to compare the eff ectiveness of stiff eners and some design parameters in the cyclic behavior of the PT connections. The design parameters are the angle thickness, the distance between the bolt line passing through the column and the heel of the angle (g 2 ), the PT force of the strands, and number of strands. First, the results of fi nite element analyses are compared to previously conducted experiments on PT connections with top and seat angles through a verifi cation study. In this way, fi nite element models of 23 PT connections are developed and analyzed under cyclic loading. Results indicate that adding the stiff eners to the angles, enhances the energy dissipation capacity, moment capacity, stiff ness and ductility of the PT connection much higher than improving other design parameters.

Thermal Resistance of Insulated Precast Concrete Sandwich Panels

Sani Mohammed Bida,Farah Nora Aznieta Abdul Aziz,Mohd Saleh Jaafar,Farzad Hejazi,Nabilah Abu Bakar 한국콘크리트학회 2021 International Journal of Concrete Structures and M Vol.15 No.6

Many nations are already working toward full implementation of energy efficiency in buildings known as Green Building. In line with this perspective, this paper aims to develop a thermally efficient precast concrete sandwich panels (PCSP) for structural applications. Therefore, an experimental investigation was carried out to determine the thermal resistance of the proposed PCSP using Hotbox method and the results were validated using finite element method (FEM) in COMSOL Multiphysics Software. The PCSP were designed with staggered shear connectors to avoid thermal bridges between the successive layers. The staggered connectors are spaced at 200 mm, 300 mm and 400 mm on each concrete layer, while the control panel is designed with 200 mm direct shear connection. In the experimental test, four (4) panels of 500 mm × 500 mm and 150 mm thick were subjected to Hotbox Test to determine the thermal resistance. The result shows that thermal resistance of the PCSP with staggered shear connection increases with increase in spacing. The PCSP with 400 mm staggered shear connectors indicates the best thermal efficiency with a thermal resistance (R value) of 2.48 m²K/W. The thermal performance was verified by FEA which shows less than 5% error coupled with a precise prediction of surface temperature gradient. This indicates that, with conventional materials, thermal path approach can be used to develop a precast concrete building with better thermal resistant properties. Hopefully, stakeholders in the green building industry would find this proposed PCSP as an alternative energy efficient load bearing panel towards sustainable and greener buildings.

Column-Tree 접합부 철골구조물의 연쇄붕괴 저항성능 평가

이업(Li, Ye),노삼영(Noh, Sam-Young),나영수(Na, Young-Soo) 대한건축학회 2022 대한건축학회 학술발표대회 논문집 Vol.42 No.2

The Column-Tree connection is widely used as a typical beam-column joint in Korea and Japan. However, there has been no studies on the progressive collapse resistance performance of an entire structure using this connection. In this study, a 5bayx8bayx7-story building was used to analyze the progressive collapse resistance performance of the column-tree connection, which was designed as an intermediate moment resisting frame. Subsequently, the one-dimensional column-tree connection model has been developed, which were then used to simulate three-dimensional behavior under column loss while considering the bolt slip effect and sub-assemblage structure model. Finally, energy-based approximate analysis has been used to efficiently evaluate progressive collapse resistance performance. Research findings has proven that the progressive collapse resistance performance of the target building satisfies the acceptance criteria, specified by the current progressive collapse guidelines of the General Services Administration.

Racking shear resistance of steel frames with corner connected precast concrete infill panels

J.C.D. Hoenderkamp,H.H. Snijder,H. Hofmeyer 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.6

When precast concrete infill panels are connected to steel frames at discrete locations, interaction at the structural interface is neither complete nor absent. The contribution of precast concrete infill panels to the lateral stiffness and strength of steel frames can be significant depending on the quality, quantity and location of the discrete interface connections. This paper presents preliminary experimental and finite element results of an investigation into the composite behaviour of a square steel frame with a precast concrete infill panel subject to lateral loading. The panel is connected at the corners to the ends of the top and bottom beams. The Frame-to-Panel-Connection, FPC4 between steel beam and concrete panel consists of two parts. A T-section with five achor bars welded to the top of the flange is cast in at the panel corner at a forty five degree angle. The triangularly shaped web of the T-section is reinforced against local buckling with a stiffener plate. The second part consists of a triangular gusset plate which is welded to the beam flange. Two bolts acting in shear connect the gusset plate to the web of the T-section. This way the connection can act in tension or compression. Experimental pull-out tests on individual connections allowed their load deflection characteristics to be established. A full scale experiment was performed on a one-storey one-bay 3 by 3 m infilled frame structure which was horizontally loaded at the top. With the characteristics of the frame-to-panel connections obtained from the experiments on individual connections, finite element analyses were performed on the infilled frame structures taking geometric and material non-linear behaviour of the structural components into account. The finite element model yields reasonably accurate results. This allows the model to be used for further parametric studies.

고연성 엔드플레이트 항복형 철골기둥-보 접합부의 설계 개념과 절차

김선희(Kim Sun-Hee),이성희(Lee Seong-Hui),채홍석(Chae Heung-Seok),김용환(Kim Yong-Hwan),최성모(Choi Sung-Mo) 대한건축학회 2007 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.27 No.1

Recently, Studies on end plate connection for beam yield have been active progressed in USA, Japan and Euro etc. These connections are widely used in European countries and USA, and its design and connection details are proposed in Eurocode 3, AISC LRFD, and FEMA 350. Further introduction of the US connection details is expected in the design criteria for beam - column connections to ensure and establish a better seismic performance. In the US criteria detail for end-plate connection, the size of the beam is controlled by guiding failure type of the beam for connections and thicker end-plate is used. FEMA 355D proposed that plastic deformation in the end-plate make ductile capacity and structural resistance. In this study, we proposed that selection of steel type make end-plate column to beam connections of better seismic performance.

철골보-기둥 용접 접합부의 초기강성에 관한 연구

손상해,김순태,유병억,안형준 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(구조계)

The purpose of this study was to propose the initial stiffness of steel welded beam-to-column connection. To simplify the analysis, neglect the influence of welding and fillet of H-section beam. According to the parameter(ζ), initial stiffness(K_(i)) increased by ratio of section modulus(Z_(b)/Z_(c)) and decreased by ratio of width/thickness. Result of analysis, range of moment resistance is 0.50M_(F)~1.00M_(F) (Unstiffened Welded Connection), 0.77M_(F)~1.00M_(F) (Continuity Plates Welded Connection) and initial stiffness(K_(i)) is 1.36×10^(8)~24.5×10^(8)(kgf·cm)(Unstiffened Welded Connection) 3.79×10^(8)~33.3x10^(8)(kgf·cm)(Continuity Plates Welded Connection).