부모멘트를 받는 합성보의 전단합성 거동에 대한 유한요소해석

신현섭(Shin, Hyun-Seop) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.8

부모멘트를 받는 합성보 슬래브에서 인장균열 발생과 균열의 진행에 따른 슬래브의 강성저하가 전단연결부 의 합성거동에 미치는 영향을 실험적으로 분석하기는 매우 어렵다. 본 논문에서는 부모멘트를 받는 합성보에서 콘크 리트 슬래브 및 강재 보, 스터드를 포함한 전단연결부 등의 형상과 물성을 최대한 실제와 유사하게 모델링하는 기법 을 이용함으로써, 부재 간 합성작용을 해석할 수 있는 3차원 유한요소모델을 개발하였다. 개발된 3차원 유한요소모델 을 이용하여 부모멘트 구간에 설치되는 합성보의 전체 휨거동 및 기존의 1차원 또는 2차원 모델로는 해석이 어려운 전단합성작용을 분석할 수 있었다. 해석결과에 따르면 부모멘트를 받는 합성보에서의 전단연결부 거동은 철근콘크리 트 슬래브의 철근비 및 인장 균열거동에 지배를 받게 됨을 알 수 있었다. 전단연결부의 하중-슬립 관계를 검토해 본 결과, 전단연결부의 슬립강성은 슬래브의 초기균열 및 철근의 항복이 발생한 시점을 기준으로 변화됨을 알 수 있었 다. 또한, 구간별로 합성율이 100% 미만으로 설계되는 부분합성 설계가 합성설계의 효율성 측면에서 더 유리할 수 있다는 기존의 실험적 연구결과를 간접적으로 확인할 수 있었다. In the composite beam subjected to the hogging moment it is very difficult to evaluate the influence of the reduction of slab stiffness due to cracks and their development on the horizontal shear behavior of shear connection. In this study, a 3D FE model is developed by which one can analyze the composite action in the composite beam subjected to the hogging moment. In this FE model, each structural member and shear connection are modeled as similar as possible to details of the composite beam. Bending behaviour, and composite action which could not be analyzed using the existing 1D or 2D FE model are investigated by the 3D model. Analysis results show that the reinforcement ratio and crack behaviour of the slab are main factors which exert a strong influence on the composite action. According to the analysis results about load-slip behavior, initial crack of slab and yielding of rebars have a influence on the slip stiffness of shear connection. The existing experimental results, that the design of partial interaction can be more efficient in designing of shear connection of the composite beams, are indirectly verified by the FE analysis.

Composite Behavior of Sandwich Panels with W-Shaped SGFRP Connectors

Huanzhi Jiang,Zhengxing Guo,Jiabin Liu 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.5

The composite behavior and structural behavior of four full-scale precast concrete sandwich panels (PCSPs) with different numberand distribution of W-shaped steel glass fiber reinforced polymer (SGFRP) shear connectors were investigated both experimentallyand theoretically in this paper. Test results showed that the number of W-shaped SGFRP connectors in the panel ends a third ratherthan in the middle section has a significant impact on the flexural capacity and the composite action of PCSPs. The ultimate loadincreased in proportion to the number of W-Connectors in both panel ends a third approximately. The shear connectors could transfera large level of shear from one wythe to the other to enable the two concrete wythes to exhibit partially composite behavior. Thedegree of partially composite action of the tested PCSPs achieved obviously different depending on the number of connectors in theends a third. Good correlation was found between experimental obtained results and the theoretical calculation results of the degreeof composite action.

Experimental and numerical studies on concrete encased embossments of steel strips under shear action for composite slabs with profiled steel decking

Noémi Seres,László Dunai 국제구조공학회 2011 Steel and Composite Structures, An International J Vol.11 No.1

The subject of the ongoing research work is to analyze the composite action of the structural elements of composite slabs with profiled steel decking by experimental and numerical studies. The mechanical and frictional interlocks result in a complex behaviour and failure under horizontal shear action. This is why the design characteristics can be determined only by standardized experiments. The aim of the current research is to develop a computational method which can predict the behaviour of embossed mechanical bond under shear actions, in order to derive the design characteristics of composite slabs with profiled steel decking. In the first phase of the research a novel experimental analysis is completed on an individual concrete encased embossment of steel strip under shear action. The experimental behaviour modes and failure mechanisms are determined. In parallel with the tests a finite element model is developed to follow the ultimate behaviour of this type of embossment, assuming that the phenomenon is governed by the failure of the steel part. The model is verified and applied to analyse the effect of embossment’s parameters on the behaviour. In the extended investigation different friction coefficients, plate thicknesses, heights and the size effects are studied. On the basis of the results the tendencies of the ultimate behaviour and resistance by the studied embossment’s characteristics are concluded.

Behaviour and design of composite beams subjected to flexure and axial load

Brendan Kirkland,Brian Uy 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.3

Composite steel-concrete beams are used frequently in situations where axial forces are introduced. Some examples include the use in cable-stayed bridges or inclined members in stadia and bridge approach spans. In these situations, the beam may be subjected to any combination of flexure and axial load. However, modern steel and composite construction codes currently do not address the effects of these combined actions. This study presents an analysis of composite beams subjected to combined loadings. An analytical model is developed based on a cross-sectional analysis method using a strategy of successive iterations. Results derived from the model show an excellent agreement with existing experimental results. A parametric study is conducted to investigate the effect of axial load on the flexural strength of composite beams. The parametric study is then extended to a number of section sizes and employs various degrees of shear connection. Design models are proposed for estimating the flexural strength of an axially loaded member with full and partial shear connection.

Numerical analysis of partially fire protected composite slabs

R. Zaharia,C. Vulcu,O. Vassart,J.-M. Franssen 국제구조공학회 2013 Steel and Composite Structures, An International J Vol.14 No.1

The paper presents a numerical investigation, done with the computer program SAFIR, in order to obtain simpler finite element models for representing the behaviour of the partially protected composite steel concrete slabs in fire situations, considering the membrane action. Appropriate understanding and modelling of the particular behaviour of composite slabs allows a safe approach, but also substantial savings on the thermal insulation that has to be applied on the underlying steel structure. The influence of some critical parameters on the behaviour and fire resistance of composite slabs such as the amount of reinforcing steel, the thickness of the slab and the edge conditions is al so highlighted. The results of the numerical analyses are compared with the results of three full scale fire tests on composite slabs that have been performed in recent years.

루프이음 반단면 프리캐스트 패널을 이용한 PSC 바닥판의 강도평가

정철헌(Chung Chul Hun),김유석(Kim Yu Seok),현병학(Hyun Byung Hak),김인규(Kim In Gyu) 대한토목학회 2009 대한토목학회논문집 A Vol.29 No.5A

프리캐스트 패널은 교량바닥판의 합성 구조부재로서 사용된다. 프리캐스트 패널의 횡방향 강재는 교량바닥판의 주철근 역할을 하며, 또한, 패널은 상부의 현장타설 콘크리트 시공시 거푸집 대용으로 적용된다. 이 연구에서는 프리캐스트 패널과 현장타설 바닥판의 합성효과를 위해 패널 상부에 도입되는 전단철근 필요성을 확인하였다. 또한, 프리캐스트 패널을 갖는 합성 바닥판에서 패널간에는 횡방향 이음부의 연속적인 거동이 요구된다. 본 연구에서는 전단철근과 루프이음을 갖는 합성바닥판의 정적실험을 수행하였다. 실험결과로부터 바닥판의 연속성 확보를 위한 루프철근 이음부의 연속성을 확인하고, 패널과 현장타설 바닥판 사이의 합성효과를 확인하였다. 전단철근이 있는 합성바닥판은 합성효과의 증가로 인해 전단철근이 없는 바닥판에 비해 약 140~164%의 극한내력을 보인다. 따라서 접합면에 도입되는 전단철근은 파괴시까지 합성거동을 확보해주는 역할을 하는 것으로 판단된다. The panels are used as a composite part of the completed deck. They replace the main bottom transverse deck reinforcement and also serve as a form surface for the cast-in-place concrete upper layer that contains the top of deck reinforcement. Research has also demonstrated that mechanical shear ties on the top of the panels are required. In a composite deck with precast panels, it is required to notice behavior of transverse joints between panels. In this paper, static tests of composite deck with shear ties and loop joints were conducted. From the results, the validity of loop joints for continuity of deck was observed. Also, a composite behavior was abserved between precast panel and slab concrete. Tested composite decks with shear ties have 140~164% ultimate strength than have no shear ties due to the increase of composite action. Therefore, the shear ties between the slabs were sufficient to enforce composite flexural behavior to failure.

Moment ratio considering composite beam action for steel special moment frames

Sang Whan Han,Soo Ik Cho,Taeo Kim,Kihak Lee 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.47 No.4

The strong column-weak beam (SCWB) moment ratio is specified in AISC 341 to prevent an abrupt column sway in steel special moment frames (SMFs) during earthquakes. Even when the SCWB requirement is satisfied for an SMF, a column-sway can develop in the SMF. This is because the contribution of the composite beam action developed in the concrete floor slab and its supporting beams was not included while calculating the SCWB moment ratio. In this study, we developed a new method for calculating the SCWB moment ratio that included the contribution of composite beam action. We evaluated the seismic collapse performance of the SMFs considering various risk categories and building heights. We demonstrated that the collapse performance of the SMFs was significantly improved by using the proposed SCWB equation that also satisfied the target performance specified in ASCE 7.

Predicting the Demand of Shear Tab Connections with Composite Beams in Fire

Mohammad A. Hajjar,Elie G. Hantouche 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.3

Shear tab connections are one of the most commonly used simple beam-end framing connections. Simple connections are designed to resist shear forces at ambient temperature. This study aims at identifying the key parameters that aff ect the behavior of composite beams with shear tab connections under fi re. Large axial forces are generated during a fi re event due to the thermal expansion of the materials. These forces, which are not considered in the design, could lead to connection failure. In this study, fi nite element (FE) models are developed in Abaqus and validated against experimental data available in the literature. The strength degradation of the steel material at elevated temperatures is accounted for using retention factors. Concrete damage plasticity is implemented to model the concrete behavior at high temperatures. FE simulations are then performed to investigate the eff ect of diff erent parameters on the behavior of shear tab connections in composite beams subjected to fi re. The main parameters are: load ratio, concrete slab temperature, shear tab thickness, setback distance, bolt diameter, in addition to the creep in the concrete and the partial composite action. This proposed research provides more guidance on the eff ect of thermally induced forces and deformations of shear tab connections with composite beams. It also provides the basis for developing simple methods of analysis.

유리 섬유복합체(GFRP) 전단연결재로 보강된 중단열 콘크리트 월 패널의 단열재 종류에 따른 휨 거동 분석

유영찬(You, Young-Chan),김준희(Kim, Jun-Hee),김호룡(Kim, Ho-Ryong),최기선(Choi, Ki-Sun) 대한건축학회 2011 大韓建築學會論文集 : 構造系 Vol.27 No.11

This paper describes a full-scale experimental program to investigate the structural behavior of insulated concrete sandwich wall panels (SWPs). Main test variables are types of insulation and the number of glass fiber reinforced polymer (GFRP) shear grids. Expanded polystyrene (EPS) and extruded polystyrene (XPS) with the same thickness of 100 ㎜ and Vacuum Insulation panel(VIP) with the thickness of 60 ㎜ are used to satisfy the building insulation requirement in Korea. Various number of GFRP shear grids are used to examine the degree of composite action of two concrete wythes. Each test result is compared with a fully-composite wall panel specimen, which has solid concrete core between concrete wythes. Fifteen SWPs were tested under displacement control subjected to four point concentrated loads. According to the test results, the specimens with EPS exhibit an enhanced load-displacement behavior in comparison with the specimens with XPS because of the relatively high surface roughness of EPS form. Most of specimen failed in the loss of shear-frictional capacity between concrete and insulation followed by rupture of GFRP shear grids. The specimen reinforced with four GFRP shear grids along the shear spans, however, exhibited a full composite behavior up to flexural failure. Based on the test results, the SWPs reinforced with GFRP grids as shear connectors hold an enhanced flexural capacity by developing a high degree of composite action.

유리 섬유복합체(GFRP) 전단연결재로 보강된 중단열 콘크리트 월 패널의 단열재 종류에 따른 휨 거동 분석

유영찬,김준희,김호룡,최기선,You, Young-Chan,Kim, Jun-Hee,Kim, Ho-Ryong,Choi, Ki-Sun 대한건축학회 2011 대한건축학회논문집 Vol.27 No.11

This paper describes a full-scale experimental program to investigate the structural behavior of insulated concrete sandwich wall panels (SWPs). Main test variables are types of insulation and the number of glass fiber reinforced polymer (GFRP) shear grids. Expanded polystyrene (EPS) and extruded polystyrene (XPS) with the same thickness of 100 mm and Vacuum Insulation panel(VIP) with the thickness of 60 mm are used to satisfy the building insulation requirement in Korea. Various number of GFRP shear grids are used to examine the degree of composite action of two concrete wythes. Each test result is compared with a fully-composite wall panel specimen, which has solid concrete core between concrete wythes. Fifteen SWPs were tested under displacement control subjected to four point concentrated loads. According to the test results, the specimens with EPS exhibit an enhanced load-displacement behavior in comparison with the specimens with XPS because of the relatively high surface roughness of EPS form. Most of specimen failed in the loss of shear-frictional capacity between concrete and insulation followed by rupture of GFRP shear grids. The specimen reinforced with four GFRP shear grids along the shear spans, however, exhibited a full composite behavior up to flexural failure. Based on the test results, the SWPs reinforced with GFRP grids as shear connectors hold an enhanced flexural capacity by developing a high degree of composite action.