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7/17/2019 Simply Supported Secondary Composite Beam
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SX014a-EN-EU Sheet 1
of 10Document Ref:
Title
CALCULATION SHEET
Example: Simply supported secondary composite beam
Eurocode Ref EN 1994-1-1
Made by Arnaud LEMAIRE Date Au ust 2005
Checked by Alain Bureau Date August 2005
Example: Simply supported secondarycomposite beam
This example deals with a simply supported secondary composite beam
under a uniformly distributed loading.
The following distributed loads are applied to the beam.
• self-weight of the beam
• concrete slab
• imposed load
The beam is a I-rolled profile in bending about the strong axis. This example
includes :
- the classification of the cross-section,
- the calculation of the effective width of the concrete flange,
- the calculation of shear resistance of a headed stud,- the calculation of the degree of shear connection,
- the calculation of bending resistance,
- the calculation of shear resistance,
- the calculation of longitudinal shear resistance of the slab,
- the calculation of deflection at serviceability limit state.
This example does not include any shear buckling verification of the web.
Partial factors
• γ G = 1,35 (permanent loads)
• γ Q = 1,50 (variable loads)
• γ M0 = 1,0
• γ M1 = 1,0
• γ V = 1,25
• γ C = 1,5
EN 1990
EN 1993-1-1
§ 6.1 (1)
EN 1994-1-1
§ 6.6.3.1
EN 1992-1-1
Example: Simply supported secondary composite beam
C r e a t e d o n W e d n e s d a y ,
M a y 1 5 ,
2 0 1 3
T h i s m a t e r i a l i s c o p y r i g h t - a l l r i g h t s r e s e r v e d .
U s e o f t h i s d o c u m e n t i s s u
b j e c t t o t h e t e r m s a n d c o n d i t i o n s o f t h e A c c e s s S t e e l L i c e n c e A g r e e m e n t
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SX014a-EN-EU Sheet 2
of 10Document Ref:
Title
CALCULATION SHEET
Example: Simply supported secondary composite beam
Eurocode Ref EN 1994-1-1
Made by Arnaud LEMAIRE Date Au ust 2005
Checked by Alain Bureau Date August 2005
Basic data
Design a composite floor beam of a multi-storey building according to the
data given below. The beam is assumed to be fully propped during
construction.
The profiled steel sheeting is transverse to the beam.
• Span length : 7,50 m
• Bay width : 3,00 m
• Slab depth : 12 cm
• Partitions : 0,75 kN/m2
• Imposed load : 2,50 kN/m2
• Reinforced Concrete density : 25 kN/m3
• Steel grade : S355
Try IPE 270
Depth ha = 270 mm
Width b = 135 mm
Web thickness t w = 6,6 mm
Flange thickness t f = 10,2 mm
Fillet r = 15 mm
Mass 36,1 kg/m
z
z
y y
t f
t w
b
ha
Euronorm
19-57
Section area Aa = 45,95 cm2
Second moment of area /yy I y = 5790 cm4
Elastic modulus /yy W el,y = 428,9 cm3
Plastic modulus /yy W pl.y = 484,0 cm3
Modulus of elasticity of steel E a= 210000 N/mm2
Example: Simply supported secondary composite beam
C r e a t e d o n W e d n e s d a y ,
M a y 1 5 ,
2 0 1 3
T h i s m a t e r i a l i s c o p y r i g h t - a l l r i g h t s r e s e r v e d .
U s e o f t h i s d o c u m e n t i s s u
b j e c t t o t h e t e r m s a n d c o n d i t i o n s o f t h e A c c e s s S t e e l L i c e n c e A g r e e m e n t
7/17/2019 Simply Supported Secondary Composite Beam
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SX014a-EN-EU Sheet 3
of 10Document Ref:
Title
CALCULATION SHEET
Example: Simply supported secondary composite beam
Eurocode Ref EN 1994-1-1
Made by Arnaud LEMAIRE Date Au ust 2005
Checked by Alain Bureau Date August 2005
Profiled steel sheeting
Thickness of sheet t = 0,75 mm
Slab depth h = 120 mm
Overall depth of the profiled steel sheeting h p = 58 mm
b1 = 62 mm b2 = 101 mm e = 207 mm
Connectors
Diameter d = 19 mm
Overall nominal height hsc = 100 mm
Ultimate tensile strength f u = 450 N/mm2
Number of shear connectors studs n = 7500 / e = 36
Number of studs per rib nr = 1
0,5hp
hp
hsc
h
h0
b1
b2
e
Concrete parameters : C 25/30
Value of the compressive strength at 28 days f ck = 25 N/mm2
Secant modulus of elasticity of concrete E cm = 33 000 N/mm2
EN 1992-1-1
§ 3.1.3
Table 3.1
To take into account the troughs of the profiled steel sheeting, the weight of
the slab is taken as :
25 × 3,0 × (0,12 – 5 ×2
06201010 , , +× 0,058) = 7,2 kN/m
Self weight of the beam : (36,1 × 9,81) × 10-3 =0,354 kN/m
Example: Simply supported secondary composite beam
C r e a t e d o n W e d n e s d a y ,
M a y 1 5 ,
2 0 1 3
T h i s m a t e r i a l i s c o p y r i g h t - a l l r i g h t s r e s e r v e d .
U s e o f t h i s d o c u m e n t i s s u
b j e c t t o t h e t e r m s a n d c o n d i t i o n s o f t h e A c c e s s S t e e l L i c e n c e A g r e e m e n t
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SX014a-EN-EU Sheet 4
of 10Document Ref:
Title
CALCULATION SHEET
Example: Simply supported secondary composite beam
Eurocode Ref EN 1994-1-1
Made by Arnaud LEMAIRE Date Au ust 2005
Checked by Alain Bureau Date August 2005
Permanent load :
G = 0,354 + 7,2 + 0,75 × 3,0 = 9,80 kN/m
Variable load (Imposed load) :
Q = 2,5 × 3,0 = 7,50 kN/m
ULS Combination :
γ G G + γ Q Q = 1,35 × 9,80 + 1,50 ×7,50 = 24,48 kN/m
EN 1990
§ 6.4.3.2
Moment diagram
M
172,13 kNm
Maximum moment at mid span :
M y,Ed = 0,125 × 24,48 × 7,502 = 172,13 kNm
Shear force diagram
V
91,80 kN
Maximum shear force at supports :
V z,Ed = 0,5 × 24,48 × 7,50 = 91,80 kN
Yield strength
Steel grade S355
The maximum thickness is 10,2 mm < 40 mm, so : f y = 355 N/mm2
Note : The National Annex may impose either the values of f y from the
Table 3.1 or the values from the product standard.
EN 1993-1-1
Table 3.1
Example: Simply supported secondary composite beam
C r e a t e d o n W e d n e s d a y ,
M a y 1 5 ,
2 0 1 3
T h i s m a t e r i a l i s c o p y r i g h t - a l l r i g h t s r e s e r v e d .
U s e o f t h i s d o c u m e n t i s s u
b j e c t t o t h e t e r m s a n d c o n d i t i o n s o f t h e A c c e s s S t e e l L i c e n c e A g r e e m e n t
7/17/2019 Simply Supported Secondary Composite Beam
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SX014a-EN-EU Sheet 5
of 10Document Ref:
Title
CALCULATION SHEET
Example: Simply supported secondary composite beam
Eurocode Ref EN 1994-1-1
Made by Arnaud LEMAIRE Date Au ust 2005
Checked by Alain Bureau Date August 2005
Section classification :
The parameter ε is derived from the yield strength : 0,81][N/mm
235
2
y
== f
ε
Note : The classification is made for the non composite beam. For the
composite beam the classification is more favourable.
EN 1993-1-1
Table 5.2
(sheet 2 of 3)
Outstand flange : flange under uniform compression
c = (b – t w – 2 r ) / 2 = (135 – 6,6 – 2 × 15)/2 = 49,2 mm
c/tf = 49,2 / 10,2 = 4,82 ≤ 9 ε = 7,29 Class 1
Internal compression part :
c = h – 2 t f – 2 r = 270 – 2 × 10,2 – 2 × 15 = 219,6 mm
c / tw = 219,6 / 6,6 = 33,3 < 72 ε = 58,3 Class 1
The class of the cross-section is the highest class (i.e the least favourable)
between the flange and the web, here : Class 1
So the ULS verifications should be based on the plastic resistance of the
cross-section since the Class is 1.
EN 1993-1-1
Table 5.2
(sheet 1 of 3)
Effective width of concrete flange
At mid-span, the total effective width may be determined by :
∑+= ei0eff,1 bbb
b0 is the distance between the centres of the outstand shear connectors, here
b0 = 0 ;
bei is the value of the effective width of the concrete flange on each side of the
web and taken as bei = Le / 8 but ≤ bi = 3,0 mbeff,1 = 0 + 7,5 / 8 = 0,9375 m, then beff = 2 × 0,9375 = 1,875 m < 3,0 m
EN 1994-1-1
Figure 5.1
At the ends, the total effective width is determined by :
∑+= eii0eff,0 bbb β
With β i = (0,55 + 0,025 Le / bei) but ≤ 1,0
= (0,55 + 0,025 × 7,5 / 0,9375) = 0,75
beff,0 = 0 + 0,75 × 7,5 / 8 = 0,703 m, then beff = 2 × 0,703 = 1,406 m < 3,0 m
EN 1994-1-1
Figure 5.1
Example: Simply supported secondary composite beam
C r e a t e d o n W e d n e s d a y ,
M a y 1 5 ,
2 0 1 3
T h i s m a t e r i a l i s c o p y r i g h t - a l l r i g h t s r e s e r v e d .
U s e o f t h i s d o c u m e n t i s s u
b j e c t t o t h e t e r m s a n d c o n d i t i o n s o f t h e A c c e s s S t e e l L i c e n c e A g r e e m e n t
7/17/2019 Simply Supported Secondary Composite Beam
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SX014a-EN-EU Sheet 6 of 10Document Ref:
Title
CALCULATION SHEET
Example: Simply supported secondary composite beam
Eurocode Ref EN 1994-1-1
Made by Arnaud LEMAIRE Date Au ust 2005
Checked by Alain Bureau Date August 2005
Design shear resistance of a headed stud
The shear resistance should be determined by :
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛ ×=
V
cmck
2
V
2
utRd
29,0;
4/8,0Min
γ
α
γ
π E f d d f k P
hsc / d = 100 / 19 = 5,26 > 4, so α = 1
EN 1994-1-1
§ 6.6.3.1
Reduction factor (k t)
For sheeting with ribs transverse to the supporting beam, the reduction factor
for shear resistance is calculated by :
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛ −= 1
7,0
p
sc
p
0
r
th
h
h
b
nk but ≤ k tmax
EN 1994-1-1
§ 6.6.4.2
Table 6.2
Where : nr = 1
h p = 58 mm
b0 = 82 mm
hsc = 100 mm
So, 717,0158
100
58
82
1
7,0t =⎟
⎠
⎞⎜⎝
⎛ −=k ≤ k tmax = 0,75
for profiled sheeting with holes.
⎟⎟ ⎠
⎞⎜⎜⎝
⎛ ×××××××=
25,1
310002519129,0;
25,1
4/194508,0Min717,0
22
Rd
π P 3
.10−
kN73,73;kN66,81Min717,0 ×=
P Rd = 52,86 kN
Example: Simply supported secondary composite beam
C r e a t e d o n W e d n e s d a y ,
M a y 1 5 ,
2 0 1 3
T h i s m a t e r i a l i s c o p y r i g h t - a l l r i g h t s r e s e r v e d .
U s e o f t h i s d o c u m e n t i s s u
b j e c t t o t h e t e r m s a n d c o n d i t i o n s o f t h e A c c e s s S t e e l L i c e n c e A g r e e m e n t
7/17/2019 Simply Supported Secondary Composite Beam
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SX014a-EN-EU Sheet 7 of 10Document Ref:
Title
CALCULATION SHEET
Example: Simply supported secondary composite beam
Eurocode Ref EN 1994-1-1
Made by Arnaud LEMAIRE Date Au ust 2005
Checked by Alain Bureau Date August 2005
Degree of shear connection
The degree of shear connection is defined by :
f c,
c
N
N =η
Where : N c is the design value of the compressive normal force in the
concrete flange
N c,f is the design value of the compressive normal force in the
concrete flange with full shear connection
EN 1994-1-1
§ 6.2.1.3 (3)
At mid-span :
The compressive normal force in the concrete flange represents the total
connection.
Ac is the cross-sectional area of concrete, so at mid-span Ac = beff hc
with hc = h - h p = 120 – 58 = 72 mm, Ac = 1875 × 62 = 116300 mm2
So, =××=== −3
c
ck ccdcf c, 10
5,1
2511630085,085,085,0
γ
f A f A N 1647 kN
The resistance of the shear connectors limits the normal force to not more
than :
N c = 0,5 n P Rd = 0,5 × 36 × 52,86 = 952 kN
So, 578,01647
952
f c,
c === N
N η
The ratio η is less than 1,0 so the connection is partial.
Verification of bending resistance
Minimum degree of shear connection
The minimum degree of shear connection for a steel section with equal
flanges is given by :
( e
y
min 030750355
-1 L ,- , f ⎟
⎟
⎠
⎞
⎜⎜
⎝
⎛ =η ) with Le ≤ 25
EN 1994-1-1
§ 6.6.1.2
Example: Simply supported secondary composite beam
C r e a t e d o n W e d n e s d a y ,
M a y 1 5 ,
2 0 1 3
T h i s m a t e r i a l i s c o p y r i g h t - a l l r i g h t s r e s e r v e d .
U s e o f t h i s d o c u m e n t i s s u
b j e c t t o t h e t e r m s a n d c o n d i t i o n s o f t h e A c c e s s S t e e l L i c e n c e A g r e e m e n t
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SX014a-EN-EU Sheet 8
of 10Document Ref:
Title
CALCULATION SHEET
Example: Simply supported secondary composite beam
Eurocode Ref EN 1994-1-1
Made by Arnaud LEMAIRE Date Au ust 2005
Checked by Alain Bureau Date August 2005
Le is the distance in sagging bending between points of zero bending momentin metres, for our example : Le = 7,5 m
So, η min = 1 – (355 / 355) (0,75 – 0,03 × 7,50) = 0,475
Then, η min = 0,475 < η = 0,578 OK
Plastic Resistance Moment at mid span
The design value of the normal force in the structural steel section is given
by :
N pl,a
= Aa f
y / γ
M0 = 4595 × 355 × 10-3 / 1,0 = 1631 kN
So, N pl,a > N c = η N c,f = 952 kN
EN 1994-1-1
§ 6.6.1.2 and
§ 6.2.1.3
With the ductile shear connectors and the cross-section of the steel beam in
Class 1, the resistance moment of the critical cross-section of the beam M Rd at
mid span is calculated by means of rigid-plastic theory except that a reduced
value of the compressive force in the concrete flange N c is used in place of
the force N cf .
Here, the plastic stress distribution is given below :
MRd
+
-
Nc=η Nc,f = 952 kN
Na = 1291 kNhn
hp 339 kN
The position of neutral axis is : hn = 263 mm
Then the design resistance for bending of the composite cross section is :
M Rd = 301,7 kNm
So, M y,Ed / M Rd = 172,2 / 301,7 = 0,57 < 1 OK
Example: Simply supported secondary composite beam
C r e a t e d o n W e d n e s d a y ,
M a y 1 5 ,
2 0 1 3
T h i s m a t e r i a l i s c o p y r i g h t - a l l r i g h t s r e s e r v e d .
U s e o f t h i s d o c u m e n t i s s u
b j e c t t o t h e t e r m s a n d c o n d i t i o n s o f t h e A c c e s s S t e e l L i c e n c e A g r e e m e n t
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SX014a-EN-EU Sheet 9
of 10Document Ref:
Title
CALCULATION SHEET
Example: Simply supported secondary composite beam
Eurocode Ref EN 1994-1-1
Made by Arnaud LEMAIRE Date Au ust 2005
Checked by Alain Bureau Date August 2005
Shear Resistance
The shear plastic resistance depends on the shear area of the steel beam,
which is given by:
Av,z = A – 2 b t f + (t w + 2 r ) t f
Av,z = 4595 – 2 × 135 × 10,2 + (6,6 + 2 × 15) × 10,2 = 2214 mm2
EN 1993-1-1
§ 6.2.6 (3)
Shear plastic resistance
845310
01
)3/355(2214
)3/( 3
M0
yzv,Rdz, pl, ,
,
f AV - =
×==
γ
kN
V z,Ed / V pl,z,Rd = 91,80 / 453,8 = 0,202 < 1 OK
EN 1994-1-1
§ 6.2.2.2
Verification to shear buckling is not required when :
hw / t w ≤ 72 ε / η
η may be conservatively taken as 1,0
hw / t w = (270 – 2 × 10,2) / 6,6 = 37,8 < 72 × 0,81 / 1,0 = 58,3 OK
EN 1993-1-1
§ 6.2.6 (6)
Longitudinal Shear Resistance of the Slab The plastic longitudinal shear stresses is given by :
xh
F v
Δ
Δ=
f
dEd
Where Δx = 7,5 / 2 = 3,75 m
EN 1992-1-1
§ 6.2.4
Figure 6.7
The value for Δ x is half the distance between the section where the moment is
zero and the section where the moment is maximum and we have two areas
for the shear resistance.
Δ F d = N c / 2 = 951,56 / 2 = 475,8 kN
hf = h - h p = 120 – 58 = 62 mm
=×
×==
375062
108,475 3
f
dEd
xh
F v
Δ
Δ2,05 N/mm2
To prevent crushing of the compression struts in the concrete flange, the
following condition should be satisfied :
f f cdEd cossin θ θ ν f v < with [ ]250/16,0 ck f −=ν and θ f = 45°
Example: Simply supported secondary composite beam
C r e a t e d o n W e d n e s d a y ,
M a y 1 5 ,
2 0 1 3
T h i s m a t e r i a l i s c o p y r i g h t - a l l r i g h t s r e s e r v e d .
U s e o f t h i s d o c u m e n t i s s u
b j e c t t o t h e t e r m s a n d c o n d i t i o n s o f t h e A c c e s s S t e e l L i c e n c e A g r e e m e n t
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SX014a-EN-EU Sheet 10
of 10Document Ref:
Title
CALCULATION SHEET
Example: Simply supported secondary composite beam
Eurocode Ref EN 1994-1-1
Made by Arnaud LEMAIRE Date Au ust 2005
Checked by Alain Bureau Date August 2005
5,45,05,1
25
250
2516,0Ed =××⎥⎦
⎤⎢⎣⎡ −×<v N/mm2 OK
The following inequality should be satisfied for the transverse reinforcement :
Asf f yd / sf ≥ vEd hf / cot θ f where f yd = 500 / 1,15 = 435 N/mm2
Assume the spacing of the bars sf = 250 mm and there is no contribution from
the profiled steel sheeting
Asf ≥ =×
××
0,1435
2506205,2
73,05 mm2
We can take 10 mm diameter bars (78,5 mm2) at 250 mm cross-centres
extending over the effective concrete breadth.
Serviceability Limit State verification
SLS Combination
G + Q = 9,80 + 7,50 = 17,30 kN/m
Deflection due to G+Q :384
)(5
y
4
I E
LQG
w
+=
EN 1990
§ 6.5.3
Where I y depends on the modular ratio (n) depending on the type of loading.
By simplification, we can take :
n0 = E a / E cm = 210 000 / 33 000 = 6,36 for primary effects (Q)
So I y = 24 540 cm4 at mid span
And n = 3 E a / E cm = 19,08 for permanent loads (G)
So I y = 18 900 cm4
1024540
507
1018900
809
210000384
575
88
4
=⎟ ⎠
⎞⎜⎝
⎛
×+
××
×=
−−
, ,
,w 16 mm
The deflection under (G+Q) is L/469
Note 1: The limits of deflection should be specified by the client. The
National Annex may specify some limits. Here the result may be
considered as fully satisfactory.
Note 2 : The National Annex may specify limits concerning the frequency of
vibration. Here the total deflection is low and the mass fairly high
and by experience there is no problem of vibration.
EN 1994-1-1
§ 7.3.1
EN 1994-1-1
§ 7.3.2
Example: Simply supported secondary composite beam
C r e a t e d o n W e d n e s d a y ,
M a y 1 5 ,
2 0 1 3
T h i s m a t e r i a l i s c o p y r i g h t - a l l r i g h t s r e s e r v e d .
U s e o f t h i s d o c u m e n t i s s u
b j e c t t o t h e t e r m s a n d c o n d i t i o n s o f t h e A c c e s s S t e e l L i c e n c e A g r e e m e n t
7/17/2019 Simply Supported Secondary Composite Beam
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Example: Simply supported secondary composite beam
SX014a-EN-EU
Quality Record
RESOURCE TITLE Example: Simply supported secondary composite beam
Reference(s)
ORIGINAL DOCUMENT
Name Company Date
Created by Arnaud LEMAIRE CTICM 14/06/05
Technical content checked by Alain BUREAU CTICM 14/06/05
Editorial content checked by D C Iles SCI 16/9/05
Technical content endorsed by the
following STEEL Partners:
1. UK G W Owens SCI 16/9/05
2. France A Bureau CTICM 16/9/05
3. Germany A Olsson SBI 15/9/05
4. Sweden C Müller RWTH 14/9/05
5. Spain J Chica Labein 16/9/05
Resource approved by TechnicalCoordinator
G W Owens SCI 10/7/06
TRANSLATED DOCUMENT
This Translation made and checked by:
Translated resource approved by:
Example: Simply supported secondary composite beam
C r e a t e d o n W e d n e s d a y ,
M a y 1 5 ,
2 0 1 3
T h i s m a t e r i a l i s c o p y r i g h t - a l l r i g h t s r e s e r v e d .
U s e o f t h i s d o c u m e n t i s s u
b j e c t t o t h e t e r m s a n d c o n d i t i o n s o f t h e A c c e s s S t e e l L i c e n c e A g r e e m e n t