Slenderness ratio of main members between interconnectors of built-up compression members

1996 ◽  
Vol 23 (6) ◽  
pp. 1295-1304 ◽  
Author(s):  
Murray C. Temple ◽  
Ghada M. Elmahdy
Keyword(s):  
Slenderness Ratio ◽  
Steel Structures ◽  
Imperfection Sensitivity ◽  
Design Standards ◽  
Limit States ◽  
Compression Members ◽  
Equivalent Slenderness Ratio ◽  
The Individual ◽  
Compressive Resistance ◽  
Steel Design

Many steel design standards, including CAN/CSA-S16.1-M89 "Limit states design of steel structures," specify maximum slenderness ratios for the individual main members between the interconnectors of built-up compression members. Previous research on which these requirements are based is reviewed. It is shown that the imperfection sensitivity due to coupled instabilities is measured from bifurcation critical loads. However, steel standards are based on a compressive resistance determined for a member with an initial out-of-straightness and a suitable residual stress pattern. It is shown that the use of an equivalent slenderness ratio equation is sufficient to predict the compressive resistance of these built-up members. Further restrictions on the slenderness ratio of built-up members between interconnectors are not warranted. Thus, the elimination of these requirements from S16.1-94 is justified. Key words: built-up members, codes, compressive resistance, coupled instabilities, equivalent slenderness ratio, interconnectors.

scholarly journals Buckling of built-up compression members in the plane of the connectors

1993 ◽  
Vol 20 (6) ◽  
pp. 895-909 ◽  
Author(s):  
Murray C. Temple ◽  
Ghada Elmahdy
Keyword(s):  
Finite Element Analysis ◽  
Slenderness Ratio ◽  
Element Analysis ◽  
The North ◽  
Compression Members ◽  
Compressive Loads ◽  
European Standards ◽  
Equivalent Slenderness Ratio ◽  
Compressive Resistance

An examination of the requirements for the design of built-up compression members in the North American and European standards and specifications reveals a great variation in the allowable maximum slenderness ratio for an individual main member, and also in the determination of an equivalent slenderness ratio. The requirements of the Canadian standard with regard to the determination of the maximum allowable slenderness ratio of a main member between points of connection can be a bit confusing.This research involved a study of model built-up members that buckled about an axis perpendicular to the plane of the connectors. Twenty-four tests were conducted on model built-up members. The theoretical analysis consisted of a finite element analysis of the model built-up struts. In addition, an equivalent slenderness ratio was calculated by several methods. These equivalent slenderness ratios were then used in conjunction with the requirements of the Canadian standard to calculate a compressive resistance, which was compared with the experimental failure load.From this research on built-up members that buckle about an axis perpendicular to the plane of the connectors it was found that at least two connectors should be used, that the slenderness ratio of the main member between points of connection has a significant effect on the compressive resistance, and that Timoshenko's equivalent slenderness ratio when used in conjunction with the Canadian standard gives results that are in the best agreement with the experimental results. Key words: battens, built-up members, compressive loads, connectors, equivalent slenderness ratio.

Limit states design of steel structures—performance factors

1980 ◽  
Vol 7 (1) ◽  
pp. 45-77 ◽  
Author(s):  
D. J. L. Kennedy ◽  
M. Gad Aly
Keyword(s):  
Slenderness Ratio ◽  
Steel Structures ◽  
Steel Beams ◽  
Limit States ◽  
Steel Columns ◽  
Performance Factors ◽  
Coefficients Of Variation ◽  
Detailed Statistical Analysis ◽  
Physical Tests ◽  
Hollow Structural Sections

A detailed statistical analysis to give ratios of mean to nominal values and associated coefficients of variation (based on raw data collected from Canadian mills on the strength and geometric properties of rolled W shapes, welded W shapes, and class H hollow structural sections) is presented. By relating the tested capacity (based on physical tests performed by others) to the predicted capacity (based on the design equations in CSA standard S16.1-1974, Steel Structures for Buildings—Limit States Design), the professional ratio and its associated coefficient of variation were determined for steel columns as a function of the slenderness ratio, as well as for laterally supported and laterally unsupported steel beams, enabling the performance factor to be determined for these members over the entire range of behaviour. A serviceability criterion for steel bridges is presented.

Local effective length factor in the equivalent slenderness ratio

1995 ◽  
Vol 22 (6) ◽  
pp. 1164-1170 ◽  
Author(s):  
Murray C. Temple ◽  
Ghada Elmahdy
Keyword(s):  
Key Words ◽  
Slenderness Ratio ◽  
Effective Length ◽  
Component Part ◽  
Square Root ◽  
Ratio Equation ◽  
Effective Length Factor ◽  
Equivalent Slenderness Ratio ◽  
Compressive Resistance

The Canadian Standard S16.1 specifies an equivalent slenderness ratio to be used when determining the compressive resistance of a built-up member when buckling occurs about an axis perpendicular to the interconnectors. This equivalent slenderness ratio is the square root of the sum of the squares of the slenderness ratio of the built-up member acting as a unit and the maximum slenderness ratio of a component part between fasteners. The Standard specifies for this second component that an effective length factor be used, the magnitude of which depends on the type of connection. An effective length factor of 0.65 is specified when welds are used. This is of concern to the authors. It is pointed out that the derivation of this equation by Bleich, and by Timoshenko and Gere, does not contain an effective length factor in the second term. The effective length factor of 0.65 comes from a paper by Duan and Chen. Results of tests on five built-up members, channels arranged in the toe-to-toe configuration, indicate that the use of an effective length factor of 0.65 gives unconservative results, especially when the member is slender. It is recommended that a factor of 1.0 be used in the second term of the equivalent slenderness ratio equation. Key words: battens, built-up members, equivalent slenderness ratio, interconnectors, standards.

scholarly journals Comparison of Design Guidelines for Hot-Rolled I-Shaped Steel Compression Members according to AISC 360-16 and EC3

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
S. Pinarbasi ◽  
T. Genc ◽  
E. Akpinar ◽  
F. Okay
Keyword(s):  
Axial Compression ◽  
Cross Section ◽  
Steel Structures ◽  
Design Guidelines ◽  
Design Specification ◽  
Steel Members ◽  
Compression Members ◽  
Steel Grades ◽  
Hot Rolled ◽  
Steel Design

Thirty-six years after its publication, Turkish Building Code for Steel Structures was replaced with a more rational specification, Specification of Design and Construction of Steel Structures (SDCSS), which was prepared almost entirely based on the current American steel design specification (AISC 360-16). European steel design specification (EC3) is also widely used in Turkey for the design of steel structures constructed with the collaboration of Turkish and European companies. It is essential for a steel designer using both SDCSS and EC3 to comprehend the basic differences between these specifications. This study aims to compare the design guidelines defined in AISC 360-16 (so in SDCSS) and EC3 for rolled I-shaped steel members subjected to axial compression thoroughly. For various steel grades, member lengths, and 153 different European I/H sections, design buckling resistances and design compressive strengths are computed and compared. It is shown that there are at most 3% difference between the effective areas computed using both specifications. It is highly recommended that the change of cross section class be allowed while calculating design buckling resistances. For the studied sections and steel grades, the resistance-to-strength ratios are found to be as high as 1.24 but not smaller than 0.907.

Study of shear provisions for stiffened plate girders

2004 ◽  
Vol 31 (1) ◽  
pp. 160-167 ◽  
Author(s):  
Robert Loov ◽  
Narayana Parthasarathi
Keyword(s):  
Steel Structures ◽  
Stiffened Plate ◽  
Limit States ◽  
Plate Girders ◽  
Shear Design ◽  
Panel Shear ◽  
Typical Design ◽  
Steel Design ◽  
Plate Girder

Steel design in Canada generally follows the provisions of CSA-S16-01 "Limit states design of steel structures" (CSA 2001). The provisions in this standard governing the shear design of stiffened plate girders set limits to the choice of web thickness, girder depth, and the spacing of intermediate stiffeners. This paper reviews the influence of each of the equations that govern the shear design of stiffened plate girders. The study reveals that many of the equations are unlikely to have any effect. Of the 13 equations that could restrict the design, only 3 are likely to have any influence on a typical design. This reveals avenues for possible simplification of design procedures.Key words: anchor panel, shear design, stiffened plate girder, tension field panel.

Limit States Design—An Innovation in Design Standards for Steel Structures

1974 ◽  
Vol 1 (1) ◽  
pp. 1-13 ◽  
Author(s):  
D. J. Laurie Kennedy
Keyword(s):  
Design Method ◽  
Steel Structures ◽  
Probability Of Failure ◽  
Simple Design ◽  
Design Standards ◽  
Limit States ◽  
Working Stress ◽  
Wide Range ◽  
Ultimate Resistance ◽  
Two Sides

The greater rationality of limit states design as compared to working stress design is developed to show that limit states design leads to a more consistent probability of failure and that neither overly safe and therefore uneconomic structures nor structures with insufficient safety should result from this design methodology.This rationality is extended in the limit states design method in that the performance of the structure and its components is checked against the various limit states at the appropriate load levels. Thus the limit states of serviceability are checked at specified load levels and of strength and stability at the factored load levels.Functions are presented for the two sides of the inequality:[Formula: see text]A comparative design of a 20-storey structure selected to provide a wide range of variables shows that limit states design as proposed results in a structure comparable to that designed by working stress method with a moderate saving in the weight of steel. Some simple design examples are worked out to show the basic similarities between working stress design and limit states design and that the two methods are of about equal complexity or simplicity. It is believed, because the designer will have to check the ultimate resistance against the effect of the factored loads, that he will develop a greater awareness of the behavior of the material and members with which he is working.

Combined flexure and torsion of I-shaped steel beams

1989 ◽  
Vol 16 (2) ◽  
pp. 124-139 ◽  
Author(s):  
Robert G. Driver ◽  
D. J. Laurie Kennedy
Keyword(s):  
Limit State ◽  
Bending Moment ◽  
Phase Behaviour ◽  
Inelastic Interaction ◽  
Steel Beams ◽  
Ultimate Limit State ◽  
Second Phase ◽  
Design Standards ◽  
Limit States ◽  
Interaction Diagram

Design standards provide little information for the design of I-shaped steel beams not loaded through the shear centre and therefore subjected to combined flexure and torsion. In particular, methods for determining the ultimate capacity, as is required in limit states design standards, are not presented. The literature on elastic analysis is extensive, but only limited experimental and analytical work has been conducted in the inelastic region. No comprehensive design procedures, applicable to limit states design standards, have been developed.From four tests conducted on cantilever beams, with varying moment–torque ratios, it is established that the torsional behaviour has two distinct phases, with the second dominated by second-order geometric effects. This second phase is nonutilizable because the added torsional restraint developed is path dependent and, if deflections had been restricted, would not have been significant. Based on the first-phase behaviour, a normal and shearing stress distribution on the cross section is proposed. From this, a moment–torque ultimate strength interaction diagram is developed, applicable to a number of different end and loading conditions. This ultimate limit state interaction diagram and serviceability limit states, based on first yield and on distortion limitations, provide a comprehensive design approach for these members. Key words: beams, bending moment, flexure, inelastic, interaction diagram, I-shaped, limit states, serviceability, steel, torsion, torque, ultimate.

Buckling Load Estimation of Two-way Grid Domes Stiffened by Diagonal Braces Under Vertical Load

2021 ◽  
Vol 62 (1) ◽  
pp. 7-23
Author(s):  
Shiro Kato ◽  
Shoji Nakazawa ◽  
Yoichi Mukaiyama ◽  
Takayuki Iwamoto
Keyword(s):  
Slenderness Ratio ◽  
Fem Analysis ◽  
Buckling Load ◽  
Vertical Load ◽  
Imperfection Sensitivity ◽  
Plastic Buckling ◽  
Elastic Plastic ◽  
Alternative Formula ◽  
Efficient Scheme ◽  
Estimation Scheme

The present study proposes an efficient scheme to estimate elastic-plastic buckling load of a shallow grid dome stiffened by diagonal braces. The dome is circular in plan. It is assumed to be subject to a uniform vertical load and to be supported by a substructure composed of columns and anti-earthquake braces. Based on FEM parametric studies considering various configurations and degrees of local imperfections, a set of formulations are presented to estimate the elastic-plastic buckling load. In the scheme, the linear buckling load, elastic buckling load, and imperfection sensitivity are first presented in terms of related parameters, and the elasticplastic buckling load is then estimated by a semi-empirical formula in terms of generalized slenderness ratio using a corresponding plastic load. For the plastic load, the present scheme adopts a procedure that it is calculated by a linear elastic FEM analysis, while an alternative formula for the plastic load is also proposed based on a shell membrane theory. The validity of the estimation scheme is finally confirmed through comparison with the results based on FEM nonlinear analysis. The formulations are so efficient and simple that the estimation may be conducted for preliminary design purposes almost with a calculator. .

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