Civil Engineering Reference
In-Depth Information
approximated. This has been done in the
Designers' Guide to EN 1994-1-1
[17]. The data used here are given below and in Fig. 3.9.
Guaranteed minimum yield strength,
f
yp
=
350 N/mm
2
Design thickness, allowing for zinc coating,
t
p
=
0.86 mm
Effective area of cross-section,
A
p
=
1178 mm
2
/m
Second moment of area,
I
p
=
0.548
×
10
6
mm
4
/m
Characteristic plastic moment of resistance,
M
pa
=
6.18 kN m/m
Distance of centroid above base,
e
=
30 mm
Distance of plastic neutral axis above base,
e
p
=
33 mm
Characteristic resistance to vertical shear,
V
pa
=
60 kN/m (approx.)
For resistance to longitudinal shear,
m
=
184 N/mm
2
k
=
0.0530 N/mm
2
For partial-interaction design,
τ
u,Rd
=
0.144 N/mm
2
Volume of concrete, 0.125 m
3
per sq. m of floor
Weight of sheeting, 0.10 kN/m
2
Weight of composite slab at 19.5 kN/m
3
,
g
k
=
0.10
+
0.125
×
19.5
=
2.54 kN/m
2
These data are illustrative only, and should not be relied upon in engineer-
ing practice.
3.4.1
Profiled steel sheeting as shuttering
In EN 1991-1-1, the density of 'unhardened concrete' is increased by
1 kN/m
3
to allow for its higher moisture content, and the imposed load
during construction is 1.0 kN/m
2
(Section 3.3), so the design loads for the
sheeting are:
•
permanent:
g
d
=
(2.54
+
0.125)
×
1.35
=
3.60 kN/m
2
(3.35)
•
variable:
q
d
=
1.0
×
1.5
=
1.5 kN/m
2
(3.36)
The top flanges of the supporting steel beams are assumed to be at least
150 mm wide. The bearing length for the sheeting should be at least
50 mm. Assuming that the sheeting is supported 25 mm from the flange
tip (Fig. 3.10) gives the effective length of each of the two spans as
L
e
=
(4000
−
150
+
50)/2
=
1950 mm
(3.37)
