Beam connections
Maximum
moment
Beam and load
43
Deflection at centre
W
L/2
WL3
WL /4
L/2
48 EI
W/2
W/2
W
5 WL3
WL /8
L
W/2
384 EI
W/2
W
a
Wb
L
b
Wab/L
Wa
L
L
WL3
48 EI
3a 4 a
L
L
3
W
a
b
L
W/2
W/2
W(
Beams
A
(a)
B
1A
C
1B
A1
B1
1
3m
48
2A
3B
3m
2B
3A
2
3
5m
5m
Part floor plan and load distribution
(b)
9
24
9
13.5
36
13.5
Imposed
21
21
Dead
1.5 m
2.0 m
5.0 m
31.5
1.5 m
31.5
Working loads on beam 2A
238
Trusses and bracing
(2) Loads on bracing (see Figure 9.20)
Point E
Load from the wind on the end gable column EF
= 9.5 5 0.5 0.578 = 13.73 kN,
Reaction at E, top of the column = 6.86 kN,
Load at E
Trusses and bracing
d =100
b = 65
(b)
Y
X
30.1
(a)
33.6
228
X
X
X
2/22 mm
holes
10
Y
2 No.100 65 10
Top chord
Net section at site joint
40
(c)
2/100 65 10
75
75
40
20 mm
bolts
70 70 10 L
50 50 6 L
Bracing
233
Tension capacity Pt = py (Ae 0.5a2 )
= 275 (1080 0.5 650)/103
= 207.6 kN > 88.3 kN.
This is satisfactory.
Joints for Members 47, 67
Use 20 mm bolts in clearance holes.
Single shear value =
Bracing
Q
18.5 kN
T
P
R
15
kN
10.6 kN
19.2 kN
(a)
243
42
.1
kN
U
77
.3
kN
V
S
W
Transverse bracing
75
3.
7
12.07 H
D
3
.5
10
.5
10
19
.32
24.14 G
12.07
.32
C
19
9.25 kN
7.45
14.89 F
B
3
9.6 kN
2.65
3.
248
Portal frames
9.1.3 Foundations
The pinned-base portal is generally adopted because it is difcult to ensure
xity without piling and it is more economical to construct. It is also advantageous to p
Elastic design
(a)
253
(b)
4m
21.8
Wind
6m
40 m
20 m
w = 20 m
Portal
Plan
Figure 9.4 Pinned base portal
RoofDead load measured on slope:
Sheeting
Insulation
Purlins (Table 4.2, P145/170, 3.97 kg/m at
218
Trusses and bracing
When the heel of the angle is in tension,
Mb = py Zx (1350 LE /rv )/1625
where LE denotes effective length from section 4.3.5 of BS 5950, rv the least
radius of gyration about
Design of a roof truss for an industrial building
(a)
H
Wind angle
0
h
F
Roof angle
22
G
w = 20 m
6m
E
Wind angle
90
EF
GH
EG
FH
0.32
0.4
0.7
223
0.6
h < 1
w
2
Plan
Section
External pressure coefficie
Analysis of trusses
(a)
213
(b)
W
W
Loads applied between nodes
Primary analysis loads at nodes
(c)
N
N
N
N
N
N
W
N
Secondary analysis of top chord as a continuous beam
Figure 8.2 Loads applies betwee
208
Compression members
Problems
7.1 A Grade S275 steel column having 6.0 m effective length for both axes
is to carry pure axial loads from the oor above. If a 254 254 UB 89 is
available, check the u
Crane columns
203
(3) Column design
Try 406 140 UB 46, the properties of which are:
A = 59.0 cm2 ;
Sx = 888.4 cm3 ;
rx = 16.29 cm,
ry = 3.02 cm,
Zx = 777.8 cm3 ;
x = 38.8;
Ix = 15 647 cm4 .
Local capa
198
Compression members
and wind only the greater effect of either need be considered in any load
combination.
7.9.5 Example: design of a crane column
(1) Building frame and loading
The single-storey
188
Compression members
(2) Column with restraints:
The restraint provides lateral support against buckling about the weak axis:
xx axis LE = 1.5L
yy axis LE = 0.85L1 or L2 , whichever is the greater.
chap07 2003/11/24 page 178 #35
7.5 kN
6 kN
6 kN
Y 34.5 D
8.55 I
202
Y
X
Roof
8.55 I
36.1 D
Above
2nd floor
Position
Y 57.9 D
17.1 I
X
Base
2nd floor
62.7 D
17.1 I
46.2
17.1
17.1
Reduced
imp. load
331.
Plastic design
w
(a)
263
(b)
b
e
x
h
d
g
d
f
X
Hinge
H
L
wL / 2
Non-uniform portal
Haunch
Figure 9.11 Non-uniform portal frame
Section
Axial
load
Bending
Plastic stress
distribution
Figure 9.12 Stress
Portal frames
(a) Stays or
eaves tie
(b) Stays or
eaves tie
B
B
H
Lm
H
Hinge
Hinge
G
LE
L2
L1
G
LE
268
F
Check bucking
resistance
F
Check buckling
resistance
L1
X
Y
Y
X
A
A
No restraint to
tension fla
Design of joints
273
h
Z
g
H
M
T
Ridge joint
Figure 9.16 Ridge joint
(4) Haunch ange
Flange force F < py ange area. The haunch section is checked for axial
load and moment in the haunch stability chec
348
Steelwork detailing
A
B
C
D
Detail V
Flange (size)
Detail X
Flange (size)
Web
plate
(size)
Detail W
A
Detail V
Web
plate
(size)
B
C
Detail W
D
5
Part elevation of girder
1
Single V
butt weld
Detai
Bolts
343
12.5 Bolts
12.5.1 Specication
The types of bolts used in steel construction are:
Ordinary Grade 4.6 or black bolts,
High strength Grade 8.8 bolts,
Preloaded HSFG friction-grip bolts.
The Bri
Results of computer analysis
333
Table 11.5 Summary of member forces (kN) and moments (kN m) for columns and truss
member connected to them
Dead
load
(DL)
Member
12(M)
Top
Bottom
23(M)
Top
Bottom
34(M
12
Steelwork detailing
12.1 Drawings
Drawings are the means by which the requirements of architects and engineers
are communicated to the fabricators and erectors, and must be presented in an
acceptab
Problems
323
Flange plate (Top & bottom)
533 210 82 kg/m UB
2 web plates
Splice location
Figure 10.35
10.6 The arrangement for a preloaded bolt grip-connection provided for a tie
carrying an ultimate