BS NA EN 1993-1-5: UK National Annex to Eurocode 3. Design of steel structures. Plated structural elements

2006·0.77 MB·English

by  British Standards Institution (BSI)

United Kingdom of Great
Britain and Northern Ireland
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BS NA EN 1993-1-5 (2006) (English): UK National
Annex to Eurocode 3. Design of steel structures.
Plated structural elements
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NA to BS EN 1993-1-5:2006
NATIONAL ANNEX
UK National Annex to
Eurocode 3: Design of
steel structures -
Part 1-5: Plated structural elements
res 91.010.30; 91.080.10
----_®
British Standards
NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW
NA to BS EN 1993-1-5:2006
Publishing and copyright information
The BSI copyright notice displayed in this document indicates when the
document was last issued.
© BSI 2008
ISBN 978 0 580 54964 9
The following BSI references relate to the work on this standard:
Committee reference B/525/l 0
Draft for comment 07/30128103 DC
Publication history
First published May 2008
Amendments issued since publication
Amd. no. Date Text affected
NA to BS EN 1993-1-5:2006
Contents
Introduction 1
NA.l Scope 1
NA.2 Nationally Determined Parameters 2
NA.3 References to non-contradictory complementary
information 4
Bibliography 5
Summary of pages
This document comprises a front cover, an inside front cover,
pages i and ii, pages 1 to 5 and a back cover.
© BSI 2008 •
NA to BS EN 1993-1-5:2006
ii • © BSI 2008 This page deliberately left blank
NA to BS EN 1993-1-5:2006
National Annex (inforInative) to
BS EN 1993-1-5:2006, Eurocode 3 - Design of
steel structures - Part 1-5: Plated structural
eleInents
Introduction
This National Annex has been prepared by BSI Subcommittee B/525/1 0,
Bridges, in consultation with B/525/31, Structural use ojsteel.
NA.l Scope
This National Annex gives:
a) the UK decisions for the Nationally Determined Parameters
described in the following subclauses of BS EN 1993-1-5:2006:
• 2.2(5)
• 3.3(1)
• 4.3(6)
• 5.1(2)
• 6.4(2)
• 8(2)
• 9.1(1)
• 9.2.1(9)
• 10(1)
• 10(5)
• C.2(1)
• C.5(2)
• C.8(1)
• C.9(3)
• D.2.2(2)
b) References to non-contradictory complementary information
(see NA.3).
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NA to BS EN 1993-1-5:2006
NA.2 Nationally Determined Parameters
NA.2.1 Effective width models for global analysis
[BS EN 1993-1-5:2006, 2.2(5)]
The recommended value of effective width parameter Aim should be
used.
NA.2.2 Shear lag at the ultimate limit state
[BS EN 1993-1-5:2006, 3.3(1)]
The recommended method in NOTE 3 should be used.
NA.2.3 Effective cross section
[BS EN 1993-1-5:2006, 4.3(6)]
The recommended value of 91l should be used.
NA.2.4 Basis [BS EN 1993-1-5:2006, 5.1(2)]
The value of 1] should be taken as 1,0 for all steels.
NA.2.5 Reduction factor kF for effective length for
resistance [BS EN 1993-1-5:2006, 6.4(2)]
NA.2.5.1 Equation (6.6) should be used for patch loading Types (a)
and (c) from Figure 6.1 for beams with longitudinal stiffeners. At
locations beyond the limits for which equation (6.6) in 6.4(2) is valid,
the treatment of such patch loading will be as for an unstiffened web.
NA.2.5.2 Equation (6.6) should not be used for patch loading
types (b) from Figure 6.1 for beams with longitudinal stiffeners. Patch
loading Type (b) from Figure 6.1 may be treated as for an unstiffened
web or may be subject to a special buckling analysis.
NA.2.6 Flange induced buckling
[BS EN 1993-1-5:2006, 8(2)]
NA.2.6.1 The design for flange induced buckling should take account
of the possible collapse of the web due to radial forces from a flange in
compression or tension curved in elevation, whether or not a beam as a
whole is curved.
NA.2.6.2 For nominally horizontal flanges, Clause 8(2) may be
applied, but the adequacy of the web should be checked using the same
analysis as for beams with flanges curved in elevation with a radius of
curvature corresponding to an out-of-flatness equal to the span/625.
NA.2.6.3 The adequacy of the web with curved flanges should be
verified by analysis of the buckling strength of the web, whether
stiffened or not, under radial forces induced by the tlanges and
associated webs in addition to any coincident global shear and
longitudinal forces. The adequacy of the web should also be verified by
use of the rules in Clause 6 in conjunction with 7.2(1).
2 • © BSI 2008
NA to BS EN 1993-1-5:2006
NA.2.6.4 For beams with only the compression flange curved the
buckling coefficients, Type (a) in Figure 6.1 should be used. For beams
with both flanges curved, the Type (b) coefficients should be used. For
nn
such a method of verification, should be taken as 2,0 in deriving 172.
NA.2.7 Stiffeners and detailing
[BS EN 1993-1-5:2006, 9.1(1)]
NA.2.7.1 Where the web of a beam is subjected to a net compressive
force, whether due to externally applied compressive force or due to
the flexural neutral axis not being at the mid-height of the web, the
effect of the net compressive force should be considered in the design
of rigid transverse stiffeners resisting shear.
NA.2.7.2 When applying 9.3.3(3), the design force in the NOTE
should not be used. Instead, intermediate rigid stiffeners should be
designed for an axial force, PEd' acting in the mid-plane of the web in
addition to any externally applied loads, where:
°
CF
PE d = T" TE d - hw t x ,8,-,r 1 - x,Ed 1-f"o'r: ;a. ->-- h w
0,8CFcr,x
CFx'Ed]~
h t 0 8 1 for a < h
PEd = TIIT E d - w X , rcr
[ 0,8CFcr,x hw w
where:
rcr is the elastic critical shear buckling stress determined in accordance
with 5.3;
O"cr,x is the elastic critical plate buckling stress for direct stress
determined in accordance with 4.4 or 4.5 for sub-panel buckling and
overall stiffened plate buckling respectively; and
O"x,Ed is the greatest longitudinal compressive stress in the web panel
under consideration.
O"x,Ed is taken as positive when compressive and should not be taken as
being greater than 0,80"cr,x'
NA.2.7.3 When applying 9.2.1, O"cr,c and O"cr,p should generally be
calculated for a panel length of a + a2 with Wo taken as the lesser
l
of b/300, a/300 and azl300. However, to safeguard against a mode of
buckling with adjacent transverse stiffeners bowing in alternate
directions, 9.2.1 should also be applied with O"cr,c and O"cr,p calculated
for a panel length of 0,5 Cal + a2). In this case, Wo should be taken as
the lesser of b/150, a/150 and a /150.
2
For panels with longitu°di nal stiffeners, the ratio O"cr,JO"cr,p should be
taken to be equal to 1, unless an alternative value can be justified by
calculations which can also be supported by either test evidence or
non-linear analysis.
NA.2.8 Minimum requirements for transverse
stiffeners [BS EN 1993-1-5:2006, 9.2.1(9)]
The value of () should be taken as 2,0.
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NA to BS EN 1993-1-5:2006
NA.2.9 Reduced stress method
[BS EN 1993-1-5:2006, 10(1)]
There are no limits of application to the methods.
NA.2.10 Reduced stress method
[BS EN 1993-1-5:2006, 10(5)]
For panels with tension and compression, equations (10.4) and (10.5)
should be applied only to the compressive parts.
NA.2.11 Use [BS EN 1993-1-5:2006, C.2(1)]
Conditions for the use of FEM analysis in design should be specified for
the particular project.
NA.2.12 Use of imperfections
[BS EN 1993-1-5:2006, C.5(2)]
The recommended approach should be adopted.
NA.2.13 Limit state criteria
[BS EN 1993-1-5:2006, C.8(1)]
The limit to principal strain for regions subjected to tensile stresses
should be 5%.
NA.2.14 Partial factors [BS EN 1993-1-5:2006, C.9(3)]
NA.2.14.1 For bridges, IMI and 1M2 as specified in the National Annex
to BS EN 1993-2 should be used.
NA.2.14.2 For buildings, IMI and 1M2 as specified in the National
Annex to BS EN 1993-1-1 should be used.
NA.2.15 Shear resistance
[BS EN 1993-1-5:2006, D.2.2(2)]
No additional information is provided.
NA.3 References to non-contradictory
complementary information
PD 6695-2, Recommendationsjor the design ojbridges to
BS EN 19931).
1) In preparation.
4 • © BSI 2008