• Title, Summary, Keyword: Semi-Rigid Behavior

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Design and analysis of non-linear space frames with semi-rigid connections

  • Sagiroglu, Merve;Aydin, Abdulkadir Cuneyt
    • Steel and Composite Structures
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    • v.18 no.6
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    • pp.1405-1421
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    • 2015
  • Semi-rigid connections are the actual behavior of beam-to-column connections in steel frames. However, the behavior of semi-rigid connections is not taken into account for the simplicity in the conventional analysis and design of steel frames. A computer-based analysis and design has been studied for the three-dimensional steel frames with semi-rigid connections. The nonlinear analysis which includes the effects of the flexibility of connections is used for this study. It is designed according to the buckling and combined stress constraints under the present loading after the joint deformations and the member end forces of the space frame are determined by the stiffness matrix method. The semi-rigid connection type is limited to the top and bottom angles with a double web angle connection. The Frye-Morris polynomial model is used to describe the non-linear behavior of semi-rigid connections. Various design examples are presented to demonstrate the efficiency of the method. The results of design and analysis of unbraced semi-rigid frames are compared to the results of unbraced rigid frames under the same design requirements.

Behavior of semi-rigid steel frames under near- and far-field earthquakes

  • Sharma, Vijay;Shrimali, Mahendra K.;Bharti, Shiv D.;Datta, Tushar K.
    • Steel and Composite Structures
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    • v.34 no.5
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    • pp.625-641
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    • 2020
  • The realistic modeling of the beam-column semi-rigid connection in steel frames attracted the attention of many researchers in the past for the seismic analysis of semi-rigid frames. Comparatively less studies have been made to investigate the behavior of steel frames with semi-rigid connections under different types of earthquake. Herein, the seismic behavior of semi-rigid steel frames is investigated under both far and near-field earthquakes. The semi-rigid connection is modeled by the multilinear plastic link element consisting of rotational springs. The kinematic hysteresis model is used to define the dynamic behavior of the rotational spring, describing the nonlinearity of the semi-rigid connection as defined in SAP2000. The nonlinear time history analysis (NTHA) is performed to obtain response time histories of the frame under scaled earthquakes at three PGA levels denoting the low, medium and high-level earthquakes. The other important parameters varied are the stiffness and strength parameters of the connections, defining the degree of semi-rigidity. For studying the behavior of the semi-rigid frame, a large number of seismic demand parameters are considered. The benchmark for comparison is taken as those of the corresponding rigid frame. Two different frames, namely, a five-story frame and a ten-story frame are considered as the numerical examples. It is shown that semi-rigid frames prove to be effective and beneficial in resisting the seismic forces for near-field earthquakes (PGA ≈ 0.2g), especially in reducing the base shear to a considerable extent for the moderate level of earthquake. Further, the semi-rigid frame with a relatively weaker beam and less connection stiffness may withstand a moderately strong earthquake without having much damage in the beams.

Dynamic analysis of steel frames with semi-rigid connections

  • Zohra, Djouaher Fatma;Nacer, Ihaddoudene Touati Abd
    • Structural Engineering and Mechanics
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    • v.65 no.3
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    • pp.327-334
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    • 2018
  • In the steel structures design, beam-to-column connections are usually considered either rigid or pinned, while their actual behavior lies between these two ideal cases. This consideration has a major influence on the results of the local and the global behavior of steel structures. This influence is noticed in the case of a static analysis, and has an important effect in the case of a dynamic analysis. In fact, pinned and rigid nodes can be considered as two specific cases of a semi-rigid behavior. To study the efficiency of the classification adopted in Eurocode 3, a numerical simulation of semi-rigid nodes has been carried out using the software ANSYS. In the aim to validate this simulation, the numerical results are compared to those of an analytical approach. After that, the validated numerical simulation has been used, to evaluate the efficiency of the classification adopted by the Eurocode 3, regarding semi-rigid connections. Finally, a new method is proposed to define a more accurate evaluation about semi-rigid connections.

A Study on the Flexibility of Semi-Rigid Steel Frames under Lateral Loadings( II ) (횡하중을 받는 반강접 철골 골조의 유연도에 관한 연구( II ) -골조 해석모형을 중심으로-)

  • Kang, Cheol Kyu;Han, Young Cheol;Lee, Gab Jo
    • Journal of Korean Society of Steel Construction
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    • v.8 no.4
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    • pp.121-131
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    • 1996
  • Semi-rigid frames are frames for whcih the connections joining the beam and column are neither fully rigid nor perfectly pinned. In reality, all steel frames are semi-rigid in nature as all connections exhibit a certain degree of flexibility under loads. For semi-rigid frmaed structures, it is tended to reduce more rigidity of the member for the nonlinear behavior of connections and the P-delta effects of framed structure. To predict the actual behavior of semi-rigid steel frames, a more realistic analysis methods which explicitly takes into account the effect of connection flexibility should be used. In this research, the effect of connection flexibility in the semi-rigid structure has been investigated. To predict the response of flexibility connected frames, the algorithm of semi-rigid steel frame is developed using connection model having nonlinear spring on end of beam.

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Analysis of the Behavior of Bolt Jointed Wood Connections by Applying Semi-Rigid Theory

  • Kim, Gwang-Chul;Lee, Jun-Jae
    • Journal of the Korean Wood Science and Technology
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    • v.28 no.4
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    • pp.72-82
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    • 2000
  • Attempts were made to analyze the behavior of single and multiple-bolted connections through theoretical methods such as European yield theory, empirical approaching method, and semi-rigid theory instead of many experimental methods that have been actually inefficient and non-economical. In the case of a single-bolted connection, if accurate characteristic values of a material could be guaranteed, it would be more convenient and economical to perform the behavior analysis using a model based on the semi-rigid theory, instead of the existing complex yield model, or the empirical formula which produces errors, giving different results from the actual ones. If the variables of equation determining the load and deformation could be appropriately controlled, the analytical method in conjunction with a semi-rigid theory could be effectively applied to obtain the desirably predicted value, considering that the appropriate solution could be derived through a simpler equation using a less difficult method compared to the existing yield model. It is concluded that analytical method with semi-rigid theory can be used in the behavior analysis of bolted connection because our developed method showed excellent analysis ability of behavior until number of bolt is two. Although our analytical method has the disadvantage that the number of bolt is limited to two, it is concluded that it has the advantage than numerical method which complicated and time-consuming.

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The Structural Behavior of Semi-Rigid Connections with Reformed T-stub by Using of SS400 Steel (SS400 강재를 사용한 개량 T-stub 반강접합부의 역학적 거동)

  • Lee, Myung Jae;Yang, Myung Sook;Cho, Won Hyuk
    • Journal of Korean Society of Steel Construction
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    • v.11 no.2
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    • pp.241-241
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    • 1999
  • The analysis and design of steel frames are usually carried out under the assumption that the connections of beam-to-column are either fully rigid or ideally pinned. However the connections actually show semi-rigid behavior in many cases. The authors investigated the structural behavior of simi-rigid connection with reformed T-stub by using of SM490 steel. The objective of the study is to investigate the structural behavior of the beam-to-column semi-rigid connection with reformed T-stub, which is made of SS400 steel. The beam-to-column connections by using reformed T-stubs were tested under monotonic loading and cyclic loading condition. The possibility of application of semi-rigid connections with reformed T-stubs was ascertained from test results.

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Development of the Nonlinear Structural Analysis Model for the Light-Weight Framed Structures (II) (경량형강 시설물의 비선형 구조해석 모델개발(II) -반강결 뼈대구조물의 해석에 대하여-)

  • 김한중;이정재
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.40 no.1
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    • pp.78-87
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    • 1998
  • In this study, semi-rigid light-weight framed structures analysis model (SERIFS) was developed by advancing the LEIFS model. This model enables us to analyze simultaneous effects of large deflection and semi-rigid connection by computing unbalanced load occurring in the process of repeated loading through equalization of bending moments and torsion. This model is also able to handle the effect of the semi-rigid connection and large deflection by modifying the elastic stiffness matrix using moment-rotation behavior of connection. Moment-rotation behavior of the semi-rigid connection was adopted from the experimental results of load-vertical displacement of frame element In conclusion, this model achieves to analyze the nonlinear and large deflection behavior on the semi-rigid and light-weight steel frame connection.

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A Study on the Behavior of Frame with Connections between H-Beams and S . H . S Columns considering Joint Flexibility (H형강보.각형강관기둥 접합부의 연성도를 고려한 골조의 거동에 관한 연구)

  • 강석봉;김이두;박순규;김재훈
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.211-218
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    • 1997
  • Analysis of structures are usually executed under the assumption that connections are either ideally pinned joint or fully rigid joint. But in general all structures is connected under the semi-rigid connections. Semi-rigid connect ions have demerits that is simplification work on connection's behavior, moment-rotation relationships of connect ions , apprehension of nonlinear analysis etc. On the other hand there is merits that is improvements of serviceability, economic efficiency, construction in predicting real behavior frames. This study is to make model of connect ions by based on experimental study and after analysis on frames considering characteristics of semi-rigid connections. semi-rigid connection's influence on the behavior of structures and fundamental data on application of structures that is connected between S H S column and H beam is exhibited.

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Effect of semi-rigid connections in improvement of seismic performance of steel moment-resisting frames

  • Feizi, M. Gholipour;Mojtahedi, A.;Nourani, V.
    • Steel and Composite Structures
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    • v.19 no.2
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    • pp.467-484
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    • 2015
  • Seismic performances of dual steel moment-resisting frames with mixed use of rigid and semi-rigid connections were investigated to control of the base shear, story drifts and the ductility demand of the elements. To this end, nonlinear seismic responses of three groups of frames with three, eight and fifteen story were evaluated. These frames with rigid, semi-rigid and combined configuration of rigid and semi-rigid connections were analyzed under five earthquake records and their responses were compared in ultimate limit state of rigid frame. This study showed that in all frames, it could be found a state of semi-rigidity and connections configuration which behaved better than rigid frame, with consideration of the base shear and story drifts criterion. Finally, some criteria were suggested to locate the best place of the semi-rigid connections for improvement of the seismic performance of steel moment-resisting frames.

Finite Elements Analysis Application to the Structural Design of the Frame Type Furniture (골조형(骨造型) 가구구조설계(家具構造設計)에의 유한요소해석 응용)

  • Chung, Woo-Yang;Eckelman, Carl A.
    • Journal of the Korean Wood Science and Technology
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    • v.23 no.3
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    • pp.8-15
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    • 1995
  • This analytical study was carried out to make quality and productivity up in designing the frame-type furniture with semi-rigid joint by understanding the mechanical and structural behavior of the joint and by evaluating the validity of application of the time-saving Finite Element Method to its structural analysis. Slope deflection equation for rigid joint was modified to describe the moment-rotation behavior of semi-rigid joint and the joint stiffness factor(Z) could be calculated to lessen the experimental expense. It was proved that Finite Element Analysis with imaginary elements having equivalent MOE to the semi-rigid joint could be the alternative method for the structural analysis of the frame-type furniture, comparing the internal rotation of the 2-dimensional beam-to-column model with two-pin(wooden dowel) from the finite element method with other available theoretical and experimental rotation value.

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