Limit States Design and Partial Factors γM0 and γM1 in Metal Eurocodes

2016 ◽  
Vol 821 ◽  
pp. 774-781
Author(s):  
Ivan Balaz ◽  
Yvona Kolekova
Keyword(s):  
Steel Structures ◽  
Limit States ◽  
Current Value

Overview of values and definitions of material partial factors γM0 and γM1 used in all 20 parts of Eurocodes EN 1993 Design of steel structures [1] and in all 5 parts of EN 1999 Design of aluminium structures [2]. Applications of the γM0 and γM1 partial factors values and definitions in all clauses of EN 1993. Comparison of safety levels of former Czechoslovak standards (ČSN) with current Eurocodes. Proposals for correction of definitions and applications of γM0 and γM1 partial factors in all clauses of EN 1993. The overview and corrections enable to do better choice from five official options aiming to change current value γM1 = 1,0 valid in EN 1993-1-1 for buildings, which were presented at CEN/TC250 SC3 meetings in October 24th 2014 and in March 19th 2015 in Berlin.

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.

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 Calibrating Partial Factors – Methodology, Input Data and Case Study of Steel Structures

2019 ◽  
Author(s):  
Vitali Nadolski ◽  
Árpád Rózsás ◽  
Miroslav Sýkora
Keyword(s):  
Input Data ◽  
Structural Reliability ◽  
Construction Materials ◽  
Steel Structures ◽  
Structural Performance ◽  
Limit States ◽  
Different Types ◽  
Load Effects ◽  
Previous Design

Partial factors are commonly based on expert judgements and on calibration to previous design formats. This inevitably results in unbalanced structural reliability for different types of construction materials, loads and limit states. Probabilistic calibration makes it possible to account for plentiful requirements on structural performance, environmental conditions, production and execution quality etc. In the light of ongoing revisions of Eurocodes and the development of National Annexes, the study overviews the methodology of probabilistic calibration, provides input data for models of basic variables and illustrates the application by a case study. It appears that the partial factors recommended in the current standards provide for a lower reliability level than that indicated in EN 1990. Different values should be considered for the partial factors for imposed, wind and snow loads, appreciating the distinct nature of uncertainties in their load effects.

Seismic retrofit of structures using rotational friction dampers with restoring force

2020 ◽  
Vol 23 (16) ◽  
pp. 3525-3540
Author(s):  
Asad Naeem ◽  
Jinkoo Kim
Keyword(s):  
Ground Motions ◽  
Design Procedure ◽  
Steel Structures ◽  
Friction Damper ◽  
Heavy Duty ◽  
Limit States ◽  
Restoring Force ◽  
Friction Dampers ◽  
Torsional Spring ◽  
Capacity Spectrum

In this study, the seismic performance of a rotational friction damper with restoring force is presented. The torsional spring friction damper consists of rotational friction pads with the heavy duty torsional springs attached on both sides of the friction damper. An analytical model and a design procedure for the damper are developed using capacity spectrum method. A parametric study is carried out to investigate the influence of the torsional spring in the response of the structure when subjected to ground motions. The seismic performances of steel structures retrofitted with the torsional spring friction damper and conventional rotational friction dampers are evaluated using fragility analysis, which shows that the structure retrofitted with the torsional spring friction damper has the smallest probability of reaching the specific limit states.

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.

DESIGN OF BOLTED CONNECTIONS SUBJECT TO TORSION AND SHEAR IN THE ULTIMATE LIMIT STRESS STATE

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Mohamed S. Abu-Yosef ◽  
Ezzeldin Y. Sayed-Ahmed ◽  
Emam A. Soliman
Keyword(s):  
Failure Modes ◽  
Focal Point ◽  
Design Method ◽  
Limit State ◽  
Bending Moment ◽  
Steel Structures ◽  
Ultimate Limit State ◽  
Shear Forces ◽  
Limit States ◽  
Ultimate Limit

Steel connections transferring axial and shear forces in addition to bending moment and/or torsional moment are widely used in steel structures. Thus, design of such eccentric connections has become the focal point of any researches. Nonetheless, behavior of eccentric connections subjected to shear forces and torsion in the ultimate limit state is still ambiguous. Most design codes of practice still conservatively use the common elastic analysis for design of the said connections even in the ultimate limit states. Yet, there are some exceptions such as the design method proposed by CAN/CSA-S16-14 which gives tabulated design aid for the ultimate limit state design of these connections based on an empirical equation that is derived for ¾ inch diameter A325 bearing type bolts and A36 steel plates. It was argued that results can also be used with a margin of error for other grade bolts of different sizes and steel of other grades. As such, in this paper, the performance of bolted connection subject to shear and torsion is experimentally investigated. The behavior, failure modes and factors affecting both are scrutinized. Twelve connections subject to shear and torsion with different bolts configurations and diameters are experimentally tested to failure. The accuracy of the currently available design equations proposed is compared to the outcomes of these tests.

Damage to buildings due to the 1989 Loma Prieta earthquake — a Canadian code perspective

1990 ◽  
Vol 17 (5) ◽  
pp. 813-834 ◽  
Author(s):  
Denis Mitchell ◽  
René Tinawi ◽  
Richard G. Redwood
Keyword(s):  
Seismic Design ◽  
Soft Soil ◽  
Steel Structures ◽  
Building Structures ◽  
Limit States ◽  
Loma Prieta Earthquake ◽  
Loma Prieta ◽  
October 17 ◽  
Design Earthquake ◽  
Observed Damage

Damage to building structures during the October 17, 1989, Loma Prieta earthquake prompted site visits by the authors. This paper presents examples of damage to buildings constructed with reinforced concrete, steel, masonry, and timber. The observed damage is used to illustrate some of the seismic design clauses in the 1990 National Building Code of Canada, the 1984 Canadian Standards Association (CSA) Standard for the Design of Concrete Structures for Buildings, and the 1989 CSA Standard for the Limit States Design of Steel Structures. The important roles played by the presence of soft soil, poor structural layouts, inadequate detailing, the lack of reinforcement in masonry, as well as inadequate connections to foundations are highlighted. Examples of the performance of upgraded structures are also given, and the concern over the presence of existing hazardous buildings in significant seismic zones in Canada is emphasized. Key words: seismic design, earthquake, Loma Prieta, structures, codes, concrete, steel, masonry, timber, upgrading.

New Canadian provisions for the design of steel beam–columns

1990 ◽  
Vol 17 (6) ◽  
pp. 873-893 ◽  
Author(s):  
D. J. L. Kennedy ◽  
A. Picard ◽  
D. Beaulieu
Keyword(s):  
Traditional Method ◽  
Geometric Analysis ◽  
Steel Structures ◽  
Second Order ◽  
Effective Length ◽  
Order Effects ◽  
Limit States ◽  
Cross Sectional ◽  
Out Of Plane ◽  
Areas Of Concern

The beam–column interaction equations of the Canadian Standards Association Standard CAN3-S16.1-M84 "Steel structures for buildings — limit states design" are reviewed and areas of concern in the formulations are addressed. The interaction equations developed for the 1989 edition of the standard, CAN3-S16.1-M89 "Limit states design of steel structures," and the methods of dealing with the areas of concern in the previous standard are presented. The new standard requires that at least an approximate second-order geometric analysis be carried out. For frames dependent on the frame stiffness for lateral stability, no longer is the traditional method, using effective length factors greater than one, allowed. Unlike the current American Institute of Steel Construction "Load and resistance factor design'' (AISC LRFD) specification, two sets of interaction equations, one for in-plane member strength and the other for out-of-plane stability, are used. This results in considerably less unnecessary conservatism. In both sets of interaction equations, the component of the moment due to translation is increased by the second-order effects. The "double ω" problem has been resolved and the minimum sway effects for the gravity loading case have been increased substantially to guard against sidesway buckling. A design example using the new standard is given. By means of a series of analytical examples, the requirements of S16.1-M89 are compared with the traditional method of S16.1-M84. For frames with direct-acting bracing, S16.1-M89 gives interaction values about 1.15 times those of the previous standard with a coefficient of variation of 0.08, while for unbraced frames the corresponding values are 0.98 and 0.07. The S16.1-M89 values reflecting greater rigor in a number of areas are considered the more valid. The S16.1-M89 standard would give comparable results to the AISC LRFD specification for class 1 sections when out-of-plane behaviour governs. The latter specification does not specifically cover cross-sectional strength and in-plane behaviour as does S16.1-M89. Key words: beam–column, stability, strength, bending, compression, standards.

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