Resistance factors for laterally unsupported steel beams and biaxially loaded steel beam columns

1984 ◽  
Vol 11 (4) ◽  
pp. 1008-1019 ◽  
Author(s):  
Karen A. Baker ◽  
D. J. Laurie Kennedy
Keyword(s):  
Key Words ◽  
Steel Structures ◽  
Resistance Factor ◽  
Steel Beams ◽  
Steel Beam ◽  
Limit States ◽  
Beam Columns ◽  
Resistance Factors ◽  
Design Resistance

Data from 30 tests conducted on laterally unsupported steel beams, and 148 tests on biaxially loaded steel beam columns conducted by others are statistically analyzed to determine resistance factors appropriate for use with the design equations given in CSA Standard CAN3-S16.1-M84 (Steel structures for buildings—limit states design). The general value of 0.90 currently given in that standard for the resistance factor is shown to be conservative by 1 –6% for both laterally unsupported beams and biaxially loaded beam columns. Key words: beam columns, beams, biaxially loaded, laterally unsupported, limit states design, resistance factors, steel.

Behaviour and ultimate tensile strength of partial joint penetration groove welds

1989 ◽  
Vol 16 (3) ◽  
pp. 384-399 ◽  
Author(s):  
Darrel P. Gagnon ◽  
D. J. Laurie Kennedy
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Key Words ◽  
Cross Section ◽  
Resistance Factor ◽  
Steel Plates ◽  
Limit States ◽  
Resistance Factors ◽  
Lateral Deflections

Partial joint penetration groove welds may be used in columns, for example, when it is not necessary to develop the full tensile capacity of the cross section. Also, where it is not feasible to make a full joint penetration groove weld because welding can be done from one side only, the strength of a partial joint penetration groove weld may be adequate. Limited experimental data have shown that the strength of partial penetration welds are proportional to their areas.A series of 75 tests on 25 mm thick, grade 300W and grade 350A steel plates, with welds made with matching electrodes and with 20–100% penetration, were conducted. The overall behaviour, the effects of percent penetration, plate strength, and the eccentricity of the load were investigated. The inherent ductility of the welds allows lateral deflections and straining to take place so that eccentrically loaded welds are as strong as concentrically loaded welds. The strength of welds is greater than the strength of the plate multiplied by the percent penetration and increases with the increasing lateral restraint that occurs with decreasing penetration. Design equations and resistance factors, based on weld strengths at least equal to the percent penetration multiplied by the ultimate tensile resistance of the plate, are proposed. Recommendations for fabrication are presented. Key words: behaviour, groove weld, limit states, partial joint penetration, strength, resistance factor, tension, ultimate.

scholarly journals Partial factors for cross-section resistance of elements in steel structures

2013 ◽  
Vol 12 (2) ◽  
pp. 213-220
Author(s):  
Marian Giżejowski ◽  
Zbigniew Stachura
Keyword(s):  
Cross Section ◽  
Steel Structures ◽  
Partial Cross Section ◽  
Live Load ◽  
Practical Application ◽  
Limit States ◽  
Resistance Factors ◽  
Safety Requirements ◽  
Permanent Load ◽  
Load Component

Issues related to safety requirements for steel elements subjected to different stress resultants in reference to limit states design philosophy according to Structural Eurocodes PN-EN and national codes PN-B are dealt with in the paper. The calibration of partial cross-section resistance factors is discussed on the basis of elements of steel floor structures where the permanent load component and the live load component of variable actions are the only components of load combinations. Final conclusions for their practical application in the codification process are formulated and values of partial factors for cross section resistance are proposed.

scholarly journals A comparative study of beam design curves against lateral torsional buckling using AISC, EC and SP

2019 ◽  
Vol 15 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Vera V Galishnikova ◽  
Tesfaldet H Gebre
Keyword(s):  
Steel Structures ◽  
Reduction Factor ◽  
Steel Beams ◽  
Steel Beam ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Vertical Loading ◽  
Beam Design ◽  
Overall Stability

Introduction. Structural stability is an essential part of design process for steel structures and checking the overall stability is very important for the determination of the optimum steel beams section. Lateral torsional buckling (LTB) normally associated with beams subject to vertical loading, buckling out of the plane of the applied loads and it is a primary consideration in the design of steel structures, consequently it may reduce the load currying capacity. Methods. There are several national codes to verify the steel beam against LTB. All specifications have different approach for the treatment of LTB and this paper is concentrated on three different methods: America Institute of Steel Construction (AISC), Eurocode (EC) and Russian Code (SP). The attention is focused to the methods of developing LTB curves and their characteristics. Results. AISC specification identifies three regimes of buckling depending on the unbraced length of the member ( Lb ). However, EC and SP utilize a reduction factor (χ LT ) to treat lateral torsional buckling problem. In general, flexural capacities according to AISC are higher than those of EC and SP for non-compact sections.

An assessment of CSA standard equations for beam column design

1981 ◽  
Vol 8 (2) ◽  
pp. 130-136 ◽  
Author(s):  
S. U. Pillai
Keyword(s):  
Steel Structures ◽  
Limit States ◽  
Beam Columns ◽  
Detailed Procedure ◽  
Standard Lead ◽  
Column Design

Comparisons are made between results of 81 recent tests on beam columns subjected to unsymmetrical and biaxially eccentric loads and the capacities predicted by design equations recommended by CSA standard S16.1-M78 — Steel Structures for Buildings — Limit States Design. It is concluded that the general provisions of the standard lead to satisfactory designs whereas the detailed procedure given in the Appendix of the standard may lead to a higher proportion of unsafe results.

scholarly journals Investigation and numerical analysis of steel beams strengthened with CFRP

2021 ◽  
Vol 37 (3) ◽  
Author(s):  
M. Khanloo ◽  
H. Dashti-Naserabadi ◽  
M. Jamshidi
Keyword(s):  
Concrete Structures ◽  
Steel Structures ◽  
High Strength ◽  
Steel Beams ◽  
Steel Beam ◽  
Reinforced Concrete Structures ◽  
Ansys Software ◽  
Variable Parameters ◽  
Design Engineers ◽  
Composite Layers

One of the most common methods of strengthening concrete structures is the use of composite fibers such as FRP. These fibers have found a special place in structural retrofitting methods due to a number of specific ability including lightness and ease of performance. Reinforced concrete structures have long been considered by design engineers for the possibility of retrofitting high strength composite steel structures. In this study, twenty-two steel beam models were modeled by ANSYS software. Variable parameters studied in the modeled steel beams can be referred to the number, orientation and thickness of composite layers.

Effective lengths of laterally continuous, laterally unsupported steel beams

1985 ◽  
Vol 12 (3) ◽  
pp. 603-616 ◽  
Author(s):  
Calvin D. Schmitke ◽  
D. J. Laurie Kennedy
Keyword(s):  
Bending Moment ◽  
Effective Length ◽  
Steel Beams ◽  
Lateral Torsional Buckling ◽  
Limit States ◽  
Torsional Buckling ◽  
Resistance Factors ◽  
New Methods ◽  
Fundamental Equations ◽  
Effective Length Method

Laterally unsupported steel beams of sufficient length may fail by elastic or inelastic lateral–torsional buckling. The fundamental equations governing elastic lateral–torsional buckling, taking into account such parameters as the shape of the bending moment diagram, the level of application of the load, and the effect of end restraints to lateral movement and to twist, are reviewed. Provisions in the current CSA Standard CAN3-S16.1-M84 are discussed. The methods currently available for dealing with the interactive lateral–torsional buckling of laterally continuous beams are evaluated statistically. Two new methods for considering this interaction, called the iterated effective length method and the equivalent beam method, are presented. A statistical evaluation of these methods shows that they are in reasonable agreement with available test data. Resistance factors for use in limit-states design are developed for the existing methods discussed as well as for the new methods. Key words: beam, bending moment, buckling, effective lengths, elastic, inelastic, lateral–torsional buckling, laterally continuous, steel.

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 buckling of Class 2 beam-column flanges

1993 ◽  
Vol 20 (6) ◽  
pp. 931-939 ◽  
Author(s):  
J. L. Dawe ◽  
T. S. Lee
Keyword(s):  
Key Words ◽  
Axial Load ◽  
Analytical Study ◽  
Local Buckling ◽  
Steel Structures ◽  
Experimental Results ◽  
Test Results ◽  
Limit States ◽  
Column Buckling ◽  
Compact Class

Test results are presented and discussed for 18 beam-column specimens subjected to flange local buckling resulting from applied axial and flexural forces. Flanges classified as Class 2 by CAN3-S16.1-M84 “Steel structures for buildings (limit states design)” are investigated. Three different sizes of W shape with different height and web thickness ratios within the Class 2 range were used in this investigation. The flange width-to-thickness ratio was kept constant at the current Class 2 limit [Formula: see text]. Results of this investigation show that the conventional value of plastic moment reduced in the presence of axial load, as based on studies in the late 1950s, does not apply to Class 2 sections. This discrepancy had previously been predicted by an analytical study using an extended Rayleigh–Ritz technique and presented in 1980. Experimental results presented herein verify these predictions. Key words: axial, beam-column, buckling, compact, Class 2, interaction, slenderness.

Review of resistance factor for steel: resistance distributions and resistance factor calibration

2002 ◽  
Vol 29 (1) ◽  
pp. 109-118 ◽  
Author(s):  
B J Schmidt ◽  
F M Bartlett
Keyword(s):  
Steel Structures ◽  
Companion Paper ◽  
Resistance Factor ◽  
Statistical Parameters ◽  
Limit States ◽  
Code Calibration ◽  
Load Combination ◽  
Current Value ◽  
Tension Members ◽  
Landmark Study

Changes in the Canadian steel industry warrant a review of the steel resistance factor in CSA Standard S16 (formerly S16.1) "Limit states design of steel structures", originally calibrated in the landmark study by Kennedy and Gad Aly in 1980. This paper presents statistical parameters for the bending, compression, and tension resistances of W, WWF, and HSS components produced since 1999 that have been derived from geometric and material properties presented in a companion paper. The resistance factor for steel was recalibrated for the live and dead load combination in the 1995 National Building Code of Canada. A resistance factor of 0.95 is suitable for laterally supported beams, stocky columns, and tension members failing by yield of the gross section, whereas the current value of 0.90 is appropriate for intermediate columns and tension members failing by fracture of the net section.Key words: code calibration, member resistance, reliability, resistance factor, safety, structural steel.

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