scholarly journals Analysis of Equivalent Flexural Stiffness of Steel–Concrete Composite Beams in Frame Structures

2021 ◽  
Vol 11 (21) ◽  
pp. 10305
Author(s):  
Mu-Xuan Tao ◽  
Zi-Ang Li ◽  
Qi-Liang Zhou ◽  
Li-Yan Xu
Keyword(s):  
Limit State ◽  
Internal Force ◽  
Composite Beams ◽  
Frame Structures ◽  
Flexural Stiffness ◽  
Beam Model ◽  
Vertical Deflection ◽  
Important Indicator ◽  
Vertical Loading ◽  
Negative Moment

Vertical deflection of a frame beam is an important indicator in the limit-state analysis of frame structures, particularly for steel–concrete composite beams, which are usually designed with large spans and heavy loads. In this study, the equivalent flexural stiffness of composite frame beams is analysed to evaluate their vertical deflection. A theoretical beam model with a spring constraint boundary and varied stiffness segments is established to consider the influence of both the rotation restraint stiffness at the beam ends and the cracked section in the negative moment region, such that the inelastic bending deformation of the composite beams can be elaborately described. By an extensive parametric analysis, a fitting formula for evaluating the equivalent flexural stiffness of the composite beams, including the effects of the rotational constraint and the concrete cracking, is obtained. The validity of the proposed formula is demonstrated by comparing its calculation accuracy with those of existing design formulas for analysing the equivalent flexural stiffness of the composite beam members. Moreover, its utility is further verified by conducting non-linear finite element simulations of structural systems to examine the serviceability limit state and the entire process evolution of beam deflections under vertical loading. Finally, to facilitate the practical application of the proposed formula in engineering design, a simplified method to calculate the deflection of composite beams, which utilises the internal force distribution of elastic analysis, is presented based on the concept of equivalent flexural stiffness.

scholarly journals Lateral distortional buckling of cellular composite-beams

2018 ◽  
Vol 11 (2) ◽  
pp. 331-356 ◽  
Author(s):  
A. D. PIASSI ◽  
J. V. DIAS ◽  
A. F. G. CALENZANI ◽  
F. C. C. MENANDRO
Keyword(s):  
Flexural Rigidity ◽  
Lateral Displacement ◽  
Limit State ◽  
Composite Beams ◽  
Bottom Flange ◽  
Distortional Buckling ◽  
Critical Moment ◽  
Negative Moment ◽  
Resistant Moment ◽  
Negative Bending

Abstract In the region of negative bending moments of continuous and semi-continuous steel and concrete composite beams, the inferior portion of the steel section is subjected to compression while the top flange is restricted by the slab, which may cause a global instability limit state know as lateral distortional buckling (LDB) characterized by a lateral displacement and rotation of the bottom flange with a distortion of the section’s web when it doesn’t have enough flexural rigidity. The ABNT NBR 8800:2008 provides an approximate procedure for the verification of this limit state, in which the resistant moment to LDB is obtained from the elastic critical moment in the negative moment region. One of the essential parameters for the evaluation of the critical moment is the composite beam’s rotational rigidity. This procedure is restricted only to to steel and concrete composite beams with sections that have plane webs. In this paper, an equation for the calculation of the rotational rigidity of cellular sections was developed in order to determine the LDB elastic critical moment. The formulation was verified by numerical analyses performed in ANSYS and its efficiency was confirmed. Finally, the procedure described in ABNT NBR 8800:2008 for the calculation of the critical LDB moment was expanded to composite beams with cellular sections in a numerical example with the appropriate modifications in geometric properties and rotational rigidity.

BEHAVIORS OF CAS AND CUS THICK-WALLED CHANNEL COMPOSITE BEAMS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4016-4021 ◽  
Author(s):  
HEOUNG-JAE CHUN ◽  
MI-JUNG PARK ◽  
JOON-HYUNG BYUN
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Beams ◽  
Beam Model ◽  
Suggested Model ◽  
Element Analysis ◽  
Vertical Loading ◽  
Open Section ◽  
Load Carrying ◽  
Walled Channel

Recently the thick open section composite beams are extensively used to replace conventional metal load carrying members and stiffeners of structural elements. However, most of studies on the open section composite beams are confined to the thin composite beams. There are some works focused on the thick composite beams but they are limited only to closed section beams. Therefore, it is required to develop an appropriate model to analyze the thick open section composite beams. In this study, the cantilever beams of two specific lay-up configurations are considered which are the circumferentially asymmetric stiffness (CAS) and circumferentially uniform stiffness (CUS) beams. Under the vertical loading at the free end, loading induced deformations are obtained for the thick beams using the suggested model. The model includes coupled stiffness and secondary warping effects. The results are compared with those obtained using thin beam model to observe the thickness effects. Those results are also compared with the finite element analysis results for the verification of the suggested model. A good agreement is obtained between the results from the suggested model and those from finite element analysis.

Flexural Bearing Capacity Research of Composite Beams with Edge Constraint Component

2013 ◽  
Vol 639-640 ◽  
pp. 807-811
Author(s):  
Yang Wang ◽  
Tian Li
Keyword(s):  
Bearing Capacity ◽  
Steel Structure ◽  
Composite Beams ◽  
Deformation And Failure ◽  
Finite Element Software ◽  
Composite Frame ◽  
Negative Moment ◽  
Flexural Bearing Capacity ◽  
Simulation Results ◽  
Current Code

To investigate the flexural bearing capacity in negative moment region of composite beams，we examined different ends constraint components. The modeling of the beam ends connected framework has been done by the finite element software ANSYS. The concrete thickness, slab reinforcement ratio and different component at the edge of the composite framework in the negative moment region are taken into account. The performance during the process of deformation and failure are got by nonlinear analysis. The flexural bearing capacity was reported, with the negative moment region of the composite frame beam, it revealed great differences when the beams are different component. Simulation results show that the concrete thickness take the biggest influence on bearing capacity. The results showed the behaviors of the composite frame beams are different with positive moment region, and calculation based on current code for design of steel structure (GB50017-2003) would be a big deviation.

The Fatigue Behavior of Negative Moment Regions of Continuous Composite Beams at Low Temperatures

1975 ◽  
Vol 2 (1) ◽  
pp. 98-115
Author(s):  
A. E. Long ◽  
K. Van Dalen ◽  
P. Csagoly
Keyword(s):  
Fatigue Behavior ◽  
Bending Moment ◽  
Composite Beams ◽  
Horizontal Shear ◽  
Shear Connectors ◽  
Significant Difference ◽  
Show Evidence ◽  
Negative Moment ◽  
Central Support ◽  
Push Out

The fatigue behavior of the negative moment region of continuous steel–concrete composite beams under Canadian temperature conditions was studied. Tests were conducted on three 26 ft 0 in. (7.92 m) long beams, continuous over a central support, and on 11 conventional push-out specimens. These were supplemented by a theoretical study of the internal forces in the beams using an iterative method of analysis.The close agreement between measured and theoretical strains and deflections indicated that good interaction was achieved throughout the length of the beams. The beams sustained 500 000 cycles of loading with no serious deterioration of composite action. The pattern of stud failures was consistent from beam to beam and reflected closely the calculated distribution of horizontal shear force at the steel–concrete interface. Stud shear connectors in the negative moment region where the slab had cracked in tension were found to be slightly less effective than studs in the positive bending moment regions.Neither the detailed study of individual connectors in the beams nor the results of the push-out tests show evidence of a reduction in the fatigue life of studs at −20 °F (−29 °C) relative to room temperature. The beams also exhibited no significant difference in their overall performance at these two temperatures.

Dynamic Analysis of Steel-Concrete Composite Frames with Partial Interaction

2012 ◽  
Vol 594-597 ◽  
pp. 904-907 ◽  
Author(s):  
Jun Xia ◽  
Z. Shen ◽  
Bin Chen
Keyword(s):  
Boundary Condition ◽  
Free Vibration ◽  
Dynamic Analysis ◽  
Free Vibration Analysis ◽  
Slip Boundary Condition ◽  
Composite Beams ◽  
Free Vibrations ◽  
Frame Structures ◽  
Shear Connection ◽  
Slip Boundary

The finite element formulations of steel-concrete composite (SCC) beams considering interlayer slip with end shear restraint were established. Free vibrations of SCC beams and frame structures under different slip boundary conditions were examined. The influences of the shear connection stiffness and the slip boundary condition on dynamic characteristics were analyzed. It is shown that the low order 8-DOF element may exhibit slip locking phenomenon in free vibration analysis for very stiff connection. The free vibration frequencies of composite beams and frame structures increase with the shear connection stiffness increasing. Besides, it is found that the natural vibration properties of SCC frame structures are significantly affected by the slip boundary condition, and it should be suitably imposed on all composite beams in dynamic analysis.

Research on Extending Span of Box Girder Bridge with Corrugated Steel Webs up to 300m

2019 ◽  
Author(s):  
Dong Xu ◽  
Xiangyong Duanmu ◽  
Yafan Zhou
Keyword(s):  
Limit State ◽  
Ultimate Limit State ◽  
Beam Model ◽  
Box Girder ◽  
Single Beam ◽  
Stability Performance ◽  
Rigid Frame ◽  
Box Girder Bridge ◽  
Girder Bridge ◽  
Under Construction

<p>In order to promote the application of steel-concrete composite structure in mountainous areas in China, a conceptual design for a PC continuous rigid frame box-girder bridge with corrugated steel webs and main span of 300 m was performed in the present paper. The combined corrugated steel web was proposed to increase the compressive area and improve the stability performance; thus, the self-weight of the composite box-girder bridge is significantly reduced. Flexural capacity of the whole section had been calculated with a single-beam model for the ultimate limit state (ULS). For the service limit state (SLS) design, the calculation for the composite box-girder bridge was conducted with the spatial grid model (SGM), from which 27 complete checking stresses in three layers (i.e. outside, inside and middle planes) of concrete plates and steel webs in every cross-section could be obtained. The stress history under construction stage was incorporated into the results obtained by SGM. Moreover, the stress states and stability performance for the composite box-girder bridge constructed were evaluated. The present investigation can provide references for the design and construction of the composite box-girder bridge with corrugated steel webs for long spans.</p>

scholarly journals Investigation of the Deformation State of a Composite Cable Space Frame Structures with a Photogrammetric Method

2018 ◽  
Vol 7 (3.2) ◽  
pp. 442
Author(s):  
Leonid Storozhenko ◽  
Dmytro Yermolenko ◽  
Grygorii Gasii
Keyword(s):  
Limit State ◽  
Three Dimensional ◽  
Frame Structures ◽  
Steel Cable ◽  
Space Frame ◽  
Long Span ◽  
Study Results ◽  
Deformation State ◽  
Vertical Displacements ◽  
Composite Steel

The article presents experimental study results of the deformation state of composite cable space frame structures, including composite steel-concrete structures. Composite cable space frame structures are three-dimensional roof framing of long-span buildings. The designed constructions are a new type of roof framing structures and consist of typical composite steel-concrete modules connected with steel cable elements. The operation of composite cable space frame structures under load is characterised by geometric nonlinearity. The aim of the research is to study the deformation state and changing the geometric shape of experimental structures under the influence of external load. The technique of studying the deformation state of the composite cable space frame structures is based on the principles of digital photogrammetry. At the limit state the composite cable space frame structures change their regular shape. In this case, the central vertical points get the greatest vertical displacements, and the displacement value decreases closer to the supports. It is defined that the investigated construction has demonstrated combined action of all its components during the test, which indicates its effectiveness. The application of the photogrammetry method made possible to determine the moment of reaching the limit state of the composite cable space frame structures concretely.  

Experimental and analytical behavior of sandwich composite beams: Comparison of natural and synthetic materials

2016 ◽  
Vol 20 (3) ◽  
pp. 287-307 ◽  
Author(s):  
Pedram Sadeghian ◽  
Dimo Hristozov ◽  
Laura Wroblewski
Keyword(s):  
Composite Beams ◽  
Bending Test ◽  
Synthetic Fiber ◽  
Sandwich Composite ◽  
Flexural Stiffness ◽  
Fiber Types ◽  
Shear Rigidity ◽  
Sandwich Composites ◽  
Core Materials ◽  
Natural And Synthetic

In this study, the flexural behavior of sandwich composite beams made of fiber-reinforced polymer (FRP) skins and light-weight cores are studied. The focus is on the comparison of natural and synthetic fiber and core materials. Two types of fiber materials, namely glass and flax fibers, as well as two types of core materials, namely polypropylene honeycomb and cork, are considered. A total of 105 small-scale sandwich beam specimens (50 mm wide) were prepared and tested under four-point bending. Test parameters were fiber types (flax and glass fibers), core materials (cork ad honeycomb), skin layers (0, 1, and 2 layers), core thicknesses (6–25 mm), and beam spans (150 and 300 mm). The load–deflection behavior, peak load, initial stiffness, and failure mode of the specimens are evaluated. Moreover, the flexural stiffness, shear rigidity, and core shear modulus of the sandwich composites are computed based on the test results of the two spans. An analytical model is also implemented to compute the flexural stiffness, core shear strength, and skin normal stress of the sandwich composites. Overall, the natural fiber and cork materials showed a promising and comparable structural performance with their synthetic counterparts.

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