1

Steel floor with a RC slab

Part

1 – Steel beam

TUTORIALS AND PROJECT

COMPLEX STEEL

STRUCTURES

PROJECT DESCRIPTION

System of floor beams (2) and plate girders (1) creates grid supported
on external walls (4) and column (4).

Typical use: industrial buildings – heavy loads.

2

FLOOR BEAM

(1)

(2)

(4)

(3)

floor beam

girder

column

3

FLOOR BEAM

Cement floor

RC slab

STEEL FLOOR BEAM

Initial height of a beam:

o

L

h

⋅

÷

=

)

20

1

25

1

(

L

L

o

⋅

= 025

,

1

Design span of the beam

:

L

L

o

05

,

1

=

– beams supported on both sides on walls

– for beams supported on one side on a wall
(e.g. cantilever beams, beam supported by girder and wall)

but

beam

o

h

L

L

⋅

+

≥

5

,

0

L – distance between walls or between wall and support (bearing)

4

FLOOR BEAM

1.0.

Floor beam

1.1.

Static scheme – single span, simply supported beam

1.2.

Loads

1.2.1.

Dead Lods „g”

Load taken from a width of RC slab supported by floor beam „a” [kN/m]

Lp.

Load type

Characteristic Load

g

k

1

Cement floor
0,02m · a · 21kN/m

3

2

RC slab
0,08m · a · 24kN/m

3

3

Floor beam

Σ =

g+p

5

FLOOR BEAM

Characteristic value of a live load:

2

kN/m

7,5

p

=

acc. to EN 1991-1-1, surface load E1 (storage area)

1.2.2.

Live (imposed) load „p”

a

p

p

k

⋅

=

1.2.3. Design load for

ULS (STR):

∑

∑

≥

≥

+

+

1

j

k,1

Q,1

j

k,

j

G,

j

1

j

k,1

0,1

Q,1

j

k,

j

G,

p

γ

g

γ

ξ

p

Ψ

γ

g

γ

q

max

6

FLOOR BEAM

1.3. Internal forces (bending moment and shear force):

where:

0,85

ξ

0,7

Ψ

1,5

γ

1,35

γ

0,1

Q1

j

G,

=

=

=

=

8

L

q

M

2

max

max

0

⋅

=

2

L

q

V

0

max

max

⋅

=

7

FLOOR BEAM

1.4.

Dimensioning - capacity check of the beam (acc. to PN-EN 1993-1-1)

1.4.1.

Section parameters

Initial profile

y

x

max

f

W

M

σ

≤

=

Profile section parameters can be found at:
„Tablic do projektowania konstrukcji metalowych”

→ I-section: „IN”, „IPE”
→ profile dimensions: h, b

f

, t

w

, t

f

, R, R

1

→ section properties of beam: A, W

y

, I

y

1.4.2.

Section class

o

L

h

⋅

÷

=

)

20

1

25

1

(

8

FLOOR BEAM

1.4.3.

ULS (Ultimate Limit State) check

1.4.3.1.

Bending moment capacity

1.4.3.2.

Shear capacity

1.4.4.

SLS (Serviceability Limit State) check

1.4.3.2.

Deflection at mid-span of beam

We assume the floor beam is restrained against LTB
(Lateral Torsional Buckling) by RC slab

9

FLOOR BEAM

1.5.

Beam support on wall

Beam can be supported on „concrete cushion”
or additional steel plate.

10

FLOOR BEAM

1.6.

Beam support on plate girder (acc. to PN-EN 1993-1-8)

The nominally pinned, bolted joint is designed. The beam in connected to the plate
girder by transverse stiffener.

11

FLOOR BEAM

12

FLOOR BEAM