lecture-6
DESCRIPTION
Steel Design University NotesTRANSCRIPT
11
University of Sheffield
Department of Civil & Structural Engineering
4. Design of Steel Structures to Eurocode 3
22
University of Sheffield
Department of Civil & Structural Engineering
Introduction to Eurocode 3
Eurocode 3 applies to the design of buildings and civil engineering works in steel
It is based on limit state principles and comes in several parts as shown in following:
EN 1993-1 Design of Steel Structures: General rules and rules for buildings.
EN 1993-2 Design of Steel Structures: Steel bridges.
EN 1993-3 Design of Steel Structures: Towers, masts and chimneys. EN 1993-4 Design of Steel Structures: Silos, tanks and pipelines.
33
University of Sheffield
Department of Civil & Structural Engineering
EN 1993-5 Design of Steel Structures: Piling.
EN 1993-6 Design of Steel Structures: Crane supporting structures.
EN 1993-1 “General rules and rules for buildings” comprises of 12 parts.
44
University of Sheffield
Department of Civil & Structural Engineering
EN 1993-1-1, (EC3) gives a general basis for the design of buildings and civil engineering works in steel
The arrangement of sections within EC3 is based on design criteria such as deflection, tension, compression, bending, shear, buckling etc, rather than on individual element types, such as beams, columns, etc
EC3 is organised into seven chapters.
There are a number of Annexes within EC3
These may be ‘normative’, in which case they have the same status as the chapters of EC3 to which they relate, or ‘informative’
Informative annexes are not mandatory but provide useful information
55
University of Sheffield
Department of Civil & Structural Engineering
Principles and application rules (clause 1.4, EC3)
The clauses in EC3 have been divided into principles and application rules
Principles encompass statements, definitions, requirements and analytical methods for which there is no permitted alternative
Application rules are generally recognized rules which follow the principles, but for which EC3 permits the use of alternative techniques
66
University of Sheffield
Department of Civil & Structural Engineering
Symbols (clause 1.6, EC3)
A complete list of symbols is included in EC3
Subscripts can be arranged in sequence as necessary, separated by a comma – for example:
Npl,Rd design plastic resistance to normal forces of the gross cross-section
77
University of Sheffield
Department of Civil & Structural Engineering
Basis of design
Serviceability limit state
Ultimate limit state
EC3 uses limit state principles and for design purposes considers the two principal categories of limit states:
The ultimate limit state is concerned with the resistance of the structure to collapse
This is generally checked by considering the strength of individual elements subject to forces determined from a suitable analysis
The overall stability of the structure must be checked
88
University of Sheffield
Department of Civil & Structural Engineering
The ultimate limit state is examined under factored load conditions
The effects on individual structural elements will be determined by analysis, and each element then treated as an isolated component for design
99
University of Sheffield
Department of Civil & Structural Engineering
Serviceability limit state
The calculated deflection is valuable as an index of the stiffness of a member or structure.
Calculations of deflection should relate to elastic behaviour of the structure.
Calculated deflections should be compared with specified maximum values.
The dynamic effects to be considered at the serviceability limit state are vibration caused by machinery and self-induced vibrations.
Resonance can be avoided by ensuring that the natural frequencies of the structure (or any part of it) are sufficiently different from those of the excitation source.
1010
University of Sheffield
Department of Civil & Structural Engineering
Actions (clause 2.3.1, EC3) Actions is the Eurocode terminology for loads and
imposed deformations
Dead and imposed loads are generally referred to in EC3 as permanent and variable actions respectively
The design values of actions (Fd) are obtained by
kFd FF Fk is the characteristic actions
is partial safety factor for actions (1.35 for permanent and 1.5 for variable actions)
F
1111
University of Sheffield
Department of Civil & Structural Engineering
Design strength (clause 2.4.1, EC3)
Design strengths, , are obtained by dX
mkd XX /kX is the characteristic strengths
m is the partial safety factor for materials
dRDesign resistance, for the member is given by
Mkd RR /is the cross-section resistance kR
M is the partial safety factor for the resistance
1212
University of Sheffield
Department of Civil & Structural Engineering
Characteristic strength (clause 3.2.1, EC3)
Nominal values of yield strength, for hot rolled structural steel yf
1313
University of Sheffield
Department of Civil & Structural Engineering
In EC3 the partial safety factor, is applied to structures and components
MPartial safety factors (clause 2.4.3 and 6.1(1), EC3)
The values for partial safety factors should be those given below:
Resistance of cross-section, 0.10 M
0.11 M Resistance of member to buckling (assessed by
checks in clause 6.3),
Resistance of cross-sections in tension to fracture,
25.12 M
1414
University of Sheffield
Department of Civil & Structural Engineering
Material coefficients (clause 3.2.6, EC3)
The material coefficients to be adopted in EC3 are as following:
Modulus of elasticity 2/210000 mmNE
Shear modulus 2/81000)1(2
mmNE
G
Poisson’s ratio 3.0
Coefficient of linear thermal expansion C /1012 6
Density 3/7850 mk g
.
1515
University of Sheffield
Department of Civil & Structural Engineering
Section classification (clause 5.5 and 6.2, EC3)
Outstand
WebInternal
Web
Flange
Internal
Flange
Rolled I-section Hollow section
Flange
Welded box section
InternalOutstand
InternalWeb
Some are internal- webs of open beams - flanges of boxes
Some are outstand- flanges of I beams- legs of angles and Tees
Rolled or welded sections may be considered an assembly of individual plate elements
1616
University of Sheffield
Department of Civil & Structural Engineering
Basis of section classification
Outstand
WebInternal
Web
Flange
Internal
Flange Rolled I-section Hollow section
Flange
Welded box section
InternalOutstand
InternalWeb
As the plate elements are relatively thin, when loaded in compression they may buckle locally.
The tendency of any plate element within the cross section to buckle may limit the axial load carrying capacity, or the bending resistance of the section, by preventing the attainment of yield.
Avoidance of premature failure arising from the effects of local buckling may be achieved by limiting the width-to-thickness ratio for individual elements within the cross section.
1717
University of Sheffield
Department of Civil & Structural Engineering
Classification of cross-sections
EC3 defines four classesfour classes of cross section.
The class into which a particular cross section falls depends upon: slendernessslenderness of each element (defined by a
width-to-thickness ratio). the compressive stress distributionstress distribution.
Classes are defined in terms of performanceperformance requirementsrequirements for resistance of bending bending momentsmoments..
1818
University of Sheffield
Department of Civil & Structural Engineering
Class 1 cross sectionsClass 1 cross sections
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
Mel
fy
Moment
LocalBuckling
Mel
Model ofBehaviour
MomentResistance
Rotation Capacity Class
1
1
1
1
1
1
1
1
Sufficient
Limited
None
None
MMpl
MMpl
MMpl
MMpl
1
2
3
4
Plastic momenton gross section
Plastic momenton gross section
Elastic momenton gross section
Plastic moment oneffective section
Mpl
Mpl
Mpl
Mpl
Mel elastic moment resistance of cross-sectionMpl plastic moment resistance of cross-sectionM applied moment rotation (curvature) of section
rotation (curvature) of section required to generate fully plastic stress distribution across section
pl
pl
rot
pl
pl
pl
pl
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
Mel
fy
Moment
LocalBuckling
Mel
Model ofBehaviour
MomentResistance
Rotation Capacity Class
1
1
1
1
1
1
1
1
Sufficient
Limited
None
None
MMpl
MMpl
MMpl
MMpl
1
2
3
4
Plastic momenton gross section
Plastic momenton gross section
Elastic momenton gross section
Plastic moment oneffective section
Mpl
Mpl
Mpl
Mpl
Mel elastic moment resistance of cross-sectionMpl plastic moment resistance of cross-sectionM applied moment rotation (curvature) of section
rotation (curvature) of section required to generate fully plastic stress distribution across section
pl
pl
rot
pl
pl
pl
pl
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
Mel
fy
Moment
LocalBuckling
Mel
Model ofBehaviour
MomentResistance
Rotation Capacity Class
1
1
1
1
1
1
1
1
Sufficient
Limited
None
None
MMpl
MMpl
MMpl
MMpl
1
2
3
4
Plastic momenton gross section
Plastic momenton gross section
Elastic momenton gross section
Plastic moment oneffective section
Mpl
Mpl
Mpl
Mpl
Mel elastic moment resistance of cross-sectionMpl plastic moment resistance of cross-sectionM applied moment rotation (curvature) of section
rotation (curvature) of section required to generate fully plastic stress distribution across section
pl
pl
rot
pl
pl
pl
pl
1919
University of Sheffield
Department of Civil & Structural Engineering
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
Mel
fy
Moment
LocalBuckling
Mel
Model ofBehaviour
MomentResistance
Rotation Capacity Class
1
1
1
1
1
1
1
1
Sufficient
Limited
None
None
MMpl
MMpl
MMpl
MMpl
1
2
3
4
Plastic momenton gross section
Plastic momenton gross section
Elastic momenton gross section
Plastic moment oneffective section
Mpl
Mpl
Mpl
Mpl
Mel elastic moment resistance of cross-sectionMpl plastic moment resistance of cross-sectionM applied moment rotation (curvature) of section
rotation (curvature) of section required to generate fully plastic stress distribution across section
pl
pl
rot
pl
pl
pl
pl
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
Mel
fy
Moment
LocalBuckling
Mel
Model ofBehaviour
MomentResistance
Rotation Capacity Class
1
1
1
1
1
1
1
1
Sufficient
Limited
None
None
MMpl
MMpl
MMpl
MMpl
1
2
3
4
Plastic momenton gross section
Plastic momenton gross section
Elastic momenton gross section
Plastic moment oneffective section
Mpl
Mpl
Mpl
Mpl
Mel elastic moment resistance of cross-sectionMpl plastic moment resistance of cross-sectionM applied moment rotation (curvature) of section
rotation (curvature) of section required to generate fully plastic stress distribution across section
pl
pl
rot
pl
pl
pl
pl
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
Mel
fy
Moment
LocalBuckling
Mel
Model ofBehaviour
MomentResistance
Rotation Capacity Class
1
1
1
1
1
1
1
1
Sufficient
Limited
None
None
MMpl
MMpl
MMpl
MMpl
1
2
3
4
Plastic momenton gross section
Plastic momenton gross section
Elastic momenton gross section
Plastic moment oneffective section
Mpl
Mpl
Mpl
Mpl
Mel elastic moment resistance of cross-sectionMpl plastic moment resistance of cross-sectionM applied moment rotation (curvature) of section rotation (curvature) of section required to generate fully plastic stress distribution across section
pl
pl
rot
pl
pl
pl
pl
Class 2 cross sectionsClass 2 cross sections
2020
University of Sheffield
Department of Civil & Structural Engineering
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
Mel
fy
Moment
LocalBuckling
Mel
Model ofBehaviour
MomentResistance
Rotation Capacity Class
1
1
1
1
1
1
1
1
Sufficient
Limited
None
None
MMpl
MMpl
MMpl
MMpl
1
2
3
4
Plastic momenton gross section
Plastic momenton gross section
Elastic momenton gross section
Plastic moment oneffective section
Mpl
Mpl
Mpl
Mpl
Mel elastic moment resistance of cross-sectionMpl plastic moment resistance of cross-sectionM applied moment rotation (curvature) of section
rotation (curvature) of section required to generate fully plastic stress distribution across section
pl
pl
rot
pl
pl
pl
pl
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
Mel
fy
Moment
LocalBuckling
Mel
Model ofBehaviour
MomentResistance
Rotation Capacity Class
1
1
1
1
1
1
1
1
Sufficient
Limited
None
None
MMpl
MMpl
MMpl
MMpl
1
2
3
4
Plastic momenton gross section
Plastic momenton gross section
Elastic momenton gross section
Plastic moment oneffective section
Mpl
Mpl
Mpl
Mpl
Mel elastic moment resistance of cross-sectionMpl plastic moment resistance of cross-sectionM applied moment rotation (curvature) of section
rotation (curvature) of section required to generate fully plastic stress distribution across section
pl
pl
rot
pl
pl
pl
pl
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
Mel
fy
Moment
LocalBuckling
Mel
Model ofBehaviour
MomentResistance
Rotation Capacity Class
1
1
1
1
1
1
1
1
Sufficient
Limited
None
None
MMpl
MMpl
MMpl
MMpl
1
2
3
4
Plastic momenton gross section
Plastic momenton gross section
Elastic momenton gross section
Plastic moment oneffective section
Mpl
Mpl
Mpl
Mpl
Mel elastic moment resistance of cross-sectionMpl plastic moment resistance of cross-sectionM applied moment rotation (curvature) of section
rotation (curvature) of section required to generate fully plastic stress distribution across section
pl
pl
rot
pl
pl
pl
pl
Class 3 cross sectionsClass 3 cross sections
2121
University of Sheffield
Department of Civil & Structural Engineering
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
Mel
fy
Moment
LocalBuckling
Mel
Model ofBehaviour
MomentResistance
Rotation Capacity Class
1
1
1
1
1
1
1
1
Sufficient
Limited
None
None
MMpl
MMpl
MMpl
MMpl
1
2
3
4
Plastic momenton gross section
Plastic momenton gross section
Elastic momenton gross section
Plastic moment oneffective section
Mpl
Mpl
Mpl
Mpl
Mel elastic moment resistance of cross-sectionMpl plastic moment resistance of cross-sectionM applied moment rotation (curvature) of section
rotation (curvature) of section required to generate fully plastic stress distribution across section
pl
pl
rot
pl
pl
pl
pl
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
Mel
fy
Moment
LocalBuckling
Mel
Model ofBehaviour
MomentResistance
Rotation Capacity Class
1
1
1
1
1
1
1
1
Sufficient
Limited
None
None
MMpl
MMpl
MMpl
MMpl
1
2
3
4
Plastic momenton gross section
Plastic momenton gross section
Elastic momenton gross section
Plastic moment oneffective section
Mpl
Mpl
Mpl
Mpl
Mel elastic moment resistance of cross-sectionMpl plastic moment resistance of cross-sectionM applied moment rotation (curvature) of section
rotation (curvature) of section required to generate fully plastic stress distribution across section
pl
pl
rot
pl
pl
pl
pl
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
fy
Moment
LocalBuckling
Mel
fy
Moment
LocalBuckling
Mel
Model ofBehaviour
MomentResistance
Rotation Capacity Class
1
1
1
1
1
1
1
1
Sufficient
Limited
None
None
MMpl
MMpl
MMpl
MMpl
1
2
3
4
Plastic momenton gross section
Plastic momenton gross section
Elastic momenton gross section
Plastic moment oneffective section
Mpl
Mpl
Mpl
Mpl
Mel elastic moment resistance of cross-sectionMpl plastic moment resistance of cross-sectionM applied moment rotation (curvature) of section
rotation (curvature) of section required to generate fully plastic stress distribution across section
pl
pl
rot
pl
pl
pl
pl
Class 4 cross sectionsClass 4 cross sections
2222
University of Sheffield
Department of Civil & Structural Engineering
Assessment of individual parts
(d)
(c)
(b)(a)
Simply supported onall four edges
t
L
b
Simply supportededge
Freeedge
b
L1
2
3
4
5
1 2 30 4 5
Plate aspect ratio L / b
Buckling coefficient k
b
L Free
Exact
k = 0.425 + (b/L)2
0.425
Behaviour of plate elements in compression
2323
University of Sheffield
Department of Civil & Structural Engineering
Maximum width-to-thickness ratios for compression parts (Table 5.2, EC3)
In EC3 each compressed (or partially compressed) element is assessed individually against the limiting width-to-thickness ratios for Class 1, 2 and 3 elements defined in Table 5.2 of EC3 (see Table 4.4).
It should be noted that the factor is given by
5.0
235
yf
2424
University of Sheffield
Department of Civil & Structural Engineering
Definition of compression width c for common cases: (a) Outstand flanges. (b) Internal compression parts
The compression widths c defined in sheets 1 and 2 always adopt the dimensions of the flat portions of the cross-sections, i.e. root radii and welds are explicitly excluded from the measurement, this was not the case in the ENV version of EC3 or BS 5950
2525
University of Sheffield
Department of Civil & Structural Engineering
Overall cross-section classification Once the classification of the individual parts of the cross-
section is determined, EC3 allows the overall cross-section classification to be defined in one of two ways:
The overall classification is taken as the highest (least favourable) class of its component parts.
The overall classification is defined by quoting both the flange and the web classification.
2626
University of Sheffield
Department of Civil & Structural Engineering
Work example WE 6-1:
Classify the hot rolled sections, 406x178x54UB, assuming in S275 and S355 steel and subjected to bending only. The section properties are:
m mh 6.4 0 2 m mb 7.1 7 7 mmt f 9.10
mmt w 7.7 m mr 2.1 0
2727
University of Sheffield
Department of Civil & Structural Engineering
2828
University of Sheffield
Department of Civil & Structural Engineering
2929
University of Sheffield
Department of Civil & Structural Engineering
3030
University of Sheffield
Department of Civil & Structural Engineering
Introduction to Introduction to
Design ofDesign of
Restrained BeamsRestrained Beams
3131
University of Sheffield
Department of Civil & Structural Engineering
Fully laterally restrained beams
Beams which are unable to Beams which are unable to move laterally are termed move laterally are termed
"restrained""restrained"
Beams which are unable to Beams which are unable to move laterally are termed move laterally are termed
"restrained""restrained"
Unaffected by out-of-plane Unaffected by out-of-plane buckling buckling
(lateral-torsional instability)(lateral-torsional instability)
Unaffected by out-of-plane Unaffected by out-of-plane buckling buckling
(lateral-torsional instability)(lateral-torsional instability)
3232
3333
University of Sheffield
Department of Civil & Structural Engineering
Beams may be considered restrained if: Full lateral restraint is provided by positive attachmentpositive attachment of a
floor system to the top flange of a simply supported beam -Many designers consider the friction generated between a
concrete slab and steel beam to constitute a positive attachment -
adequate torsional restraint of the compression flange is provided, for example by profiled roof sheeting
closely spaced bracing elements are provided such that the minor axis slendernessminor axis slenderness is low
Sections bent about their minor axis cannot fail by lateral torsional instability and it is unlikely that sections with high torsional and lateral stiffness (eg RHS) will fail in this way.
Fully laterally restrained beams
3434
University of Sheffield
Department of Civil & Structural Engineering
In a simple single span, failure occurs when design value of the bending moment MMEdEd exceeds design moment resistance of the cross-section MMc,Rdc,Rd.
EC3 sets this limit as a shear force of 50% of the plastic shear resistance
Magnitude depends on section shapesection shape, material material strengthstrength and section classification.section classification.
Where shear force on cross-section is smallsmall its effecteffect on the resistance moment may be neglected.neglected.
RdcEd MM ,
3535
University of Sheffield
Department of Civil & Structural Engineering
Class 1 and 2 cross-sections: moment resistance is the design plastic resistance moment.
Class 3 cross-sections: moment resistance is the design elastic resistance moment.
0
,,,
M
yplRdplRdc
fWMM
0
.min,,,
M
yelRdelRdc
fWMM
class 4 cross-section, the design local buckling resistance.
0
.min,,
M
yeffRdc
fWM
maxmin,el d/IW
dmax = maximum distance from the centroid to the edge of the section
3636
University of Sheffield
Department of Civil & Structural Engineering
Work example WE 6-2:
Calculate the moment of resistance, , of the section 152x152x23UC in grade S355 steel (ignoring the influence of shear force), The section properties
are:
RdcM ,
m mh 4.1 5 2 m mb 2.1 5 2 mmt f 8.6
mmt w 8.5 m mr 6.73182 cmW p l
3164 cmW el
3737
University of Sheffield
Department of Civil & Structural Engineering
3838
University of Sheffield
Department of Civil & Structural Engineering
3939
University of Sheffield
Department of Civil & Structural Engineering
Beams with holes in the tension flange at the critical cross-sectionBeams with holes in the tension flange at the critical cross-section Check that ratio of net area/gross area of the flange is not
so small that the section would rupture on the net sectionrupture on the net section before the gross section yielded.gross section yielded.
Bolt holes in the tension zone of the web
should be considered similarly
Holes in the compression zone (both web and flange) may
be ignored unless oversized or slotted
02. ///9.0 MMuyfnetf ffAA
This check will be satisfied provided.
If not, a reduced flange area may be assumed which satisfies the limit.
02
.9.0
M
yf
M
unetf fAfA
4040
University of Sheffield
Department of Civil & Structural Engineering
Continuous (statically indeterminate) structures
The design moment resistance at the point of maximum moment obtained from an elastic analysis will not normally
lead to collapse
Redistribution of moments enables the structure to withstand loads beyond that which produces the first hinge until eventually sufficient hinges have formed to turn the structure into a mechanism
Load F Elastic - plasticF F
F F
L/2 L/2 L/2 L/2
Plastic
Behaviouraccording tosimple plastictheory
Actual behaviour
F F
Elastic
A B C
F F
L L
Fc
F1st hinge
Fyield
Deflection under load
Load deflection curve for a statically indeterminate beam
4141
University of Sheffield
Department of Civil & Structural Engineering
Resistance of cross-sections – shear (clause 6.2.6, EC3)
The pattern of shear stress in an I section assuming elastic behaviour
max
V
ht
3
2
h
Cross - section
b
h
Cross - section
Variation of shearstress
Variation of shearstress
t f
tw
Vhb
4I
max
Vhb
2I
h
4b
1
Vhb
2I
The design value of the shear force, , at each cross-section should satisfy
EdV
RdcEd VV ,
As almost all the shear force is carried by the web and since the variation in shear stress through the web is quite small it is sufficiently accurate for design to assume an average shear stress over the web.
4242
University of Sheffield
Department of Civil & Structural Engineering
MO
yvRdpl
fAV
)3/(
,
vAWhere is the shear area, for general structural cross-sections are given in clause 6.2.3(3). vA
Plastic shear resistance, of the shear area ( ) is given by:
RdplV , vA
The most common ones are shown below:
Rolled I and H sections, load parallel to the web:
wwfwfv thbuttrttbAA 22
Rolled channel sections, load parallel to the web:
fwfv trttbAA 2
4343
University of Sheffield
Department of Civil & Structural Engineering
Welded I, H and box sections, load parallel to the web:
wwv thA
Welded I, H, channel and box sections, load parallel to the flanges:
wwv thAA
Rolled rectangular hollow section of uniform thickness, load parallel to the depth:
hbAhAv /
4444
University of Sheffield
Department of Civil & Structural Engineering
Rolled rectangular hollow section of uniform thickness, load parallel to the width :
Circular hollow section and tubes of uniform thickness:
hbAbAv /
/2AAv
4545
University of Sheffield
Department of Civil & Structural Engineering
Shear buckling need not be considered provided:
for an unstiffened web
for a stiffened web
where is the buckling factor defined in Annex A.3 of EN 1993-1-5.
k
72w
w
t
h
kt
h
w
w 72
4646
University of Sheffield
Department of Civil & Structural Engineering
Calculate the plastic shear resistance, , for the class 1 section 610x229x101UB in grade S355 steel. The section properties are:
RdplV ,
Work example WE 6-3:
m mh 6.6 0 2 m mb 6.2 2 7 mmt f 8.14
mmtw 5.10 m mr 7.1 2212900 mmA
441075780 mmI
4747
University of Sheffield
Department of Civil & Structural Engineering
4848
University of Sheffield
Department of Civil & Structural Engineering
Resistance of cross-sections – bending and shear (clause 6.2.8, EC3)
If the design shear force exceeds 50% of the plastic exceeds 50% of the plastic shear resistanceshear resistance, the design moment resistance of the cross-section is reduced.
4949
University of Sheffield
Department of Civil & Structural Engineering
Design plastic moment is calculated using a reduced reduced strength for the shear area, strength for the shear area, given bygiven by:
yyr ff )1(
)5.0(12
,
2
,RdplEd
Rdpl
Ed VVforV
V
The reduced design plastic resistance moment allowing for the shear force may alternatively be obtained as follows for equal flanged section, bending about major axis:
RdVyM ,,
RdcyM
y
w
wyplRdVy M
f
t
AWM ,,
0
2
,,, 4
www thA where
5050
University of Sheffield
Department of Civil & Structural Engineering
Deflections (clause 7.2.1, EC3)
Deflections and vibrations must be limited to avoid: adverse affects to the appearance impaired use of the structure discomfort to the occupants damage to the finishes and contents of a building.
Acceptable limits for deflections should be agreed between the client, designer and competent authorities.
5151
University of Sheffield
Department of Civil & Structural Engineering
Vertical deflection limits
Numerical values for deflections limits are not provided in both EC3 and EN 1990.
The UK National Annex may define similar limits to those given in Table 4.6, and is likely to propose that permanent actions be taken as zero in serviceability checks, essentially reverting to the practice in BS 5950, which is to check deflections under unfactored imposed loading.
5252
University of Sheffield
Department of Civil & Structural Engineering
Design procedure for restrained beams:
(1) Perform structural analysis and calculate design loads on the beam for both ultimate limit state and serviceability limit state.
(2) Determinate maximum design bending moment and shear force along the beam for ultimate limit state.
(3) Select a suitable beam-section.
y
MEdupl f
MW 0.
5353
University of Sheffield
Department of Civil & Structural Engineering
Web Flange Flange WebAxisx-x
Axisy-y
Axis x-x Axis y-yAxisx-x
Axis y-yAxisx-x
Axis y-y
h b s t r d b/2t d/s Ix Iy rx ry Zx Zy Sx Sy u x H J A
kg/m mm mm mm mm mm mm cm4 cm4 cm cm cm3 cm3 cm3 cm3 dm6 cm4 cm2
838x292x176 175.9 834.9 291.7 14 18.8 17.8 761.7 7.76 54.4 246000 7799 33.1 5.9 5893 535 6808 842 0.856 46.5 13 221 224
762x267x197 196.8 769.8 268 15.6 25.4 16.5 686 5.28 44 240000 8175 30.9 5.71 6234 610 7167 959 0.869 33.2 11.3 404 251
762x267x173 173 762.2 266.7 14.3 21.6 16.5 686 6.17 48 205300 6850 30.5 5.58 5387 514 6198 807 0.864 38.1 9.39 267 220
762x267x147 146.9 754 265.2 12.8 17.5 16.5 686 7.58 53.6 168500 5455 30 5.4 4470 411 5156 647 0.858 45.2 7.4 159 187
762x267x134 133.9 750 264.4 12 15.5 16.5 686 8.53 57.2 150700 4788 29.7 5.3 4018 362 4644 570 0.854 49.8 6.46 119 171
686x254x170 170.2 692.9 255.8 14.5 23.7 15.2 615.1 5.4 42.4 170300 6630 28 5.53 4916 518 5631 811 0.872 31.8 7.42 308 217
686x254x152 152.4 687.5 254.5 13.2 21 15.2 615.1 6.06 46.6 150400 5784 27.8 5.46 4374 455 5000 710 0.871 35.5 6.42 220 194
686x254x140 140.1 683.5 253.7 12.4 19 15.2 615.1 6.68 49.6 136300 5183 27.6 5.39 3987 409 4558 638 0.868 38.7 5.72 169 178
686x254x125 125.2 677.9 253 11.7 16.2 15.2 615.1 7.81 52.6 118000 4383 27.2 5.24 3481 346 3994 542 0.862 43.9 4.8 116 159
610x305x238 238.1 635.8 311.4 18.4 31.4 16.5 540 4.96 29.3 209500 15840 26.3 7.23 6589 1017 7486 1574 0.886 21.3 14.5 785 303
610x305x179 179 620.2 307.1 14.1 23.6 16.5 540 6.51 38.3 153000 11410 25.9 7.07 4935 743 5547 1144 0.886 27.7 10.2 340 228
610x305x149 149.2 612.4 304.8 11.8 19.7 16.5 540 7.74 45.8 125900 9308 25.7 7 4111 611 4594 937 0.886 32.7 8.17 200 190
610x229x140 139.9 617.2 230.2 13.1 22.1 12.7 547.6 5.21 41.8 111800 4505 25 5.03 3622 391 4142 611 0.875 30.6 3.99 216 178
610x229x125 125.1 612.2 229 11.9 19.6 12.7 547.6 5.84 46 98610 3932 24.9 4.97 3221 343 3676 535 0.873 34.1 3.45 154 159
610x229x113 113 607.6 228.2 11.1 17.3 12.7 547.6 6.6 49.3 87320 3434 24.6 4.88 2874 301 3281 469 0.87 38 2.99 111 144
610x229x101 101.2 602.6 227.6 10.5 14.8 12.7 547.6 7.69 52.2 75780 2915 24.2 4.75 2515 256 2881 400 0.864 43.1 2.52 77 129
533x210x122 122 544.5 211.9 12.7 21.3 12.7 476.5 4.97 37.5 76040 3388 22.1 4.67 2793 320 3196 500 0.877 27.6 2.32 178 155
533x210x109 109 539.5 210.8 11.6 18.8 12.7 476.5 5.61 41.1 66820 2943 21.9 4.6 2477 279 2828 436 0.875 30.9 1.99 126 139
533x210x101 101 536.7 210 10.8 17.4 12.7 476.5 6.03 44.1 61520 2692 21.9 4.57 2292 256 2612 399 0.874 33.2 1.81 101 129
533x210x92 92.14 533.1 209.3 10.1 15.6 12.7 476.5 6.71 47.2 55230 2389 21.7 4.51 2072 228 2360 356 0.872 36.5 1.6 75.7 117
533x210x82 82.2 528.3 208.8 9.6 13.2 12.7 476.5 7.91 49.6 47540 2007 21.3 4.38 1800 192 2059 300 0.864 41.6 1.33 51.5 105
457x191x98 98.3 467.2 192.8 11.4 19.6 10.2 407.6 4.92 35.8 45730 2347 19.1 4.33 1957 243 2232 379 0.881 25.7 1.18 121 125
457x191x89 89.3 463.4 191.9 10.5 17.7 10.2 407.6 5.42 38.8 41020 2089 19 4.29 1770 218 2014 338 0.88 28.3 1.04 90.7 114
457x191x82 82 460 191.3 9.9 16 10.2 407.6 5.98 41.2 37050 1871 18.8 4.23 1611 196 1831 304 0.877 30.9 0.922 69.2 104
457x191x74 74.3 457 190.4 9 14.5 10.2 407.6 6.57 45.3 33320 1671 18.8 4.2 1458 176 1653 272 0.877 33.9 0.818 51.8 94.6
457x191x67 67.1 453.4 189.9 8.5 12.7 10.2 407.6 7.48 48 29380 1452 18.5 4.12 1296 153 1471 237 0.872 37.9 0.705 37.1 85.5
457x152x82 82.1 465.8 155.3 10.5 18.9 10.2 407.6 4.11 38.8 36590 1185 18.7 3.37 1571 153 1811 240 0.873 27.4 0.591 89.2 105
457x152x74 74.2 462 154.4 9.6 17 10.2 407.6 4.54 42.5 32670 1047 18.6 3.33 1414 136 1627 213 0.873 30.1 0.518 65.9 94.5
457x152x67 67.2 458 153.8 9 15 10.2 407.6 5.13 45.3 28930 913 18.4 3.27 1263 119 1453 187 0.869 33.6 0.448 47.7 85.6
457x152x60 59.8 454.6 152.9 8.1 13.3 10.2 407.6 5.75 50.3 25500 795 18.3 3.23 1122 104 1287 163 0.868 37.5 0.387 33.8 76.2
457x152x52 52.3 449.8 152.4 7.6 10.9 10.2 407.6 6.99 53.6 21370 645 17.9 3.11 950 84.6 1096 133 0.859 43.9 0.311 21.4 66.6
Torsional Constant
Area of section
Radius of Gyration Elastic Modulus Plastic ModulusBuckling
ParameterTorsional
IndexWarping Constant
Universal Beams to BS4 Part1 1993 - Dimensions & Properties
Designation
Mass Per metre
Depth of section
Width of section
ThicknessRoot radius
Depth betw een
f illets
Ratios for Local Buckling Second Moment of Area
Section table for some universal beams
5454
University of Sheffield
Department of Civil & Structural Engineering
(4) Cross-section classification.
(5) Check bending resistance of cross-section.
(6) Check shear resistance of cross-section.
(7) Check shear buckling.
(8) Check bending and shear.
(9) Check deflection: using design bending moment under serviceability limit state.