Corus Special Profiles
Bulb flats For plate stiffening
Introduction
Plate stiffening
Introduction
Bulb flats are tailor made for plate stiffening applications. Their special shape provides significant benefits when compared with other types of stiffener.
Corus Special Profiles is part
Customer service
of Corus, the international metals
Our priority at Special Profiles is
company.
staying close to the customer. Daily contact is maintained through
Our business is a leading producer
Corus’ network of overseas offices
of bulb flat profiles. We have been
and agents.
supplying the shipbuilding and bridge building industries for over
Bulb flats sales are co-ordinated
40 years from our rolling mill facility
from Corus’ Skinningrove sales
at Skinningrove, in the North East
office. A rolling guideline is regularly
of England. We are certified to
produced, providing details of when
ISO 9002.
each bulb flat size will be rolled and despatched. An electronic version is
Bulb flats are tailor made for plate
also available on our website:
stiffening applications. Their special
www.corus-specialprofiles.com
shape provides significant benefits compared with other types of
Customer service for bulb flats is
stiffener. Bulb flats provide benefits
co-ordinated from the Skinningrove
during the initial steel construction
office. The team at the mill utilises
phase, and also during the working
Corus’ shipping and distribution
life of a ship or other products on
organisation to meet customer
which they are used.
delivery requirements on a world-wide basis.
Recognition of the advantages that bulb flats provide is resulting in their increased usage for shipbuilding and bridge building.
Shipbuilding
At Special Profiles, we recognise that reducing building time and costs and minimising “through life costs” during a vessel’s life are major issues.
Bulb flats offer many unique benefits
•
for achieving these objectives: •
•
Bulb flats are easier and quicker
with no sharp corners, assists
to clean in ballast tanks and
effective and efficient painting.
cargo holds. Material is less
They are “ready to use” plate stiffeners. Compared with
•
The rounded profile of a bulb flat,
likely to become trapped in •
Bulb flats can also reduce
“blind corners” and require
welded or fabricated stiffeners,
coating material costs because
extended time in port for removal.
bulb flats are more cost effective.
they have a smaller surface area
This can dramatically reduce the
than other stiffeners with the
lifetime maintenance cost.
The unique shape of a bulb
same section modulus.
flat distributes steel to maximise
•
Access for inspection and
resistance to buckling. This
The advantages of bulb flats stretch
welding is easier, and the
results in a more efficient
beyond the initial building phase
compact shape of a bulb flat
strength to weight ratio compared
to provide benefits during the
also results in less welding,
with other stiffeners such as flat
working life of a ship. Their shape
if damaged profiles need to
bars or structural angles.
has inherent corrosion resistance
be replaced.
features, and they are more “user •
The compact shape of a bulb
friendly” for repair and maintenance,
Please contact our sales office for
flat offers easy access for
compared with other stiffeners:
further information or a copy of our
welding and painting.
rolling guideline. •
•
The curved surface of a bulb
The asymmetric bulb flat shape
flat is less likely to trap moisture
lends itself to simplified collar
or pollutants which can initiate
connection when compared to
corrosion.
alternative stiffeners such as ‘T’s and angles.
Shipbuilding
Shipbuilding
Bridge building
Recognition of the benefits which
•
The rounded shape of a bulb flat
bulb flats provide is resulting in
provides inherent corrosion
increased usage in bridges around
resistance features. It enhances
the world, both large and small.
drainage, and minimises dirt
The Jiangyin and Øresund bridges
and moisture traps.
are the most well known developments in recent years
Corus offers advice to consultant
incorporating bulb flats.
engineers and designers on how to incorporate bulb flats in bridges. We
The advantages that bulb flats offer
have conducted research in
assist both the initial construction
conjunction with Imperial College,
phase as well as the working life of
London and the Bridge Engineering
the bridge:
Division of the UK Department of the Environment. This work investigated
•
Bulb flats can save weight
the buckling capacity of plate and
compared with flat bars and
bulb flat stiffener arrangements.
angles which offer equivalent buckling resistance.
Please contact our sales office for further information.
•
Bulb flats are more cost effective than fabricated plate stiffeners.
•
Bulb flats reduce painting costs, by having a smaller surface area than other stiffener arrangements
•
The compact shape of a bulb flat provides easy access for welding, painting and inspection.
Bulb flats fulfil a range of applications in bridges, such as stiffening of box girders and plate girders, and stiffening of steel decks on small br idges.
Bridge building
Bridge building
Dimensions and properties
Dimensions and properties Width
Thickness
b [mm]
[mm]
120
140
160
180
200
220
240
260
280
300
320
340
370
400
430
t
6 7 8 6.5 7 8 10 7 8 9 11.5 8 9 10 11.5 8.5 9 10 11 12 9 10 11 12 9.5 10 11 12 10 11 12 10.5 11 12 13 11 12 13 11.5 12 13 14 12 13 14 15 12.5 13 14 15 16 13 14 15 16 14 15 17 20
Mass per Unit Length G [kg/m]
Bulb Height c
d
r
[mm]
[mm]
7.31 8.25 9.19 9.21 9.74 10.8 13.0 11.4 12.7 14.0 17.3 14.8 16.2 17.6 19.7 17.8 18.5 20.1 21.7 23.2 21.0 22.8 24.5 26.2 24.4 25.4 27.4 29.3 28.3 30.3 32.4 32.4 33.5 35.7 37.9 36.7 39.0 41.5 41.2 42.5 45.0 47.5 46.1 48.8 51.5 54.2 53.1 54.6 57.5 60.5 63.5 60.8 63.9 67.0 70.2 70.6 73.9 80.6 90.8
17 17 17 19 19 19 19 22 22 22 22 25 25 25 25 28 28 28 28 28 31 31 31 31 34 34 34 34 37 37 37 40 40 40 40 43 43 43 46 46 46 46 49 49 49 49 53.5 53.5 53.5 53.5 53.5 58 58 58 58 62.5 62.5 62.5 62.5
17.7 17.7 17.7 19.7 19.7 19.7 19.7 22.2 22.2 22.2 22.2 25.5 25.5 25.5 25.5 28.8 28.8 28.8 28.8 28.8 32.1 32.1 32.1 32.1 35.4 35.4 35.4 35.4 38.7 38.7 38.7 42.0 42.0 42.0 42.0 45.3 45.3 45.3 48.6 48.6 48.6 48.6 52.0 52.0 52.0 52.0 56.9 56.9 56.9 56.9 56.9 61.9 61.9 61.9 61.9 66.8 66.8 66.8 66.8
Additional sizes may be available by agreement:
Bulb Width
Bulb Radius
80 & 100 DIN range 180, 200, 230 and 250 JIS range
* Values for H are taken about the line of attachment.
Surface Area
[mm]
Area of crosssection F [cm 2]
5 5 5 5.5 5.5 5.5 5.5 6 6 6 6 7 7 7 7 8 8 8 8 8 9 9 9 9 10 10 10 10 11 11 11 12 12 12 12 13 13 13 14 14 14 14 15 15 15 15 16.5 16.5 16.5 16.5 16.5 18 18 18 18 19.5 19.5 19.5 19.5
9.31 10.5 11.7 11.7 12.4 13.8 16.6 14.6 16.2 17.8 21.8 18.9 20.7 22.5 25.2 22.6 23.6 25.6 27.6 29.6 26.8 29.0 31.2 33.4 31.2 32.4 34.9 37.3 36.1 38.7 41.3 41.2 42.6 45.5 48.4 46.7 49.7 52.8 52.6 54.2 57.4 60.6 58.8 62.2 65.5 69.0 67.8 69.6 73.3 77.0 80.7 77.4 81.4 85.4 89.4 89.7 94.1 103.0 115.0
0.276 0.278 0.280 0.319 0.320 0.322 0.326 0.365 0.367 0.369 0.374 0.411 0.413 0.415 0.418 0.456 0.457 0.459 0.461 0.463 0.501 0.503 0.505 0.507 0.546 0.547 0.549 0.551 0.593 0.593 0.595 0.636 0.637 0.639 0.641 0.681 0.683 0.685 0.727 0.728 0.730 0.732 0.772 0.774 0.776 0.778 0.839 0.840 0.842 0.844 0.846 0.907 0.908 0.910 0.912 0.975 0.976 0.980 0.986
U [m2 /m]
Dimensions and properties
Distance of Centre of Gravity dx [mm]
72.0 70.7 69.6 83.7 83.1 81.8 79.2 96.6 94.9 93.6 91.1 109 107 106 104 122 121 119 118 117 136 134 132 130 148 147 146 144 162 160 158 175 174 172 170 189 187 185 202 201 199 197 215 213 211 209 236 235 232 230 228 258 255 252 250 277 274 269 263
d y [mm]
5.3 5.6 6.0 5.8 5.9 6.3 7.0 6.4 6.8 7.1 8.1 7.4 7.7 8.1 8.6 8.2 8.4 8.7 9.0 9.4 9.1 9.3 9.6 10.0 9.9 10.0 10.3 10.6 10.7 11.0 11.3 11.6 11.7 11.9 12.2 12.4 12.6 12.9 13.3 13.4 13.6 13.9 14.1 14.3 14.6 14.8 15.4 15.4 15.6 15.9 16.1 16.6 16.8 17.0 17.2 17.9 18.1 18.5 19.3
Second Moment of Area Axis x-x [cm4] 133 148 164 228 241 266 316 373 411 448 544 609 665 717 799 902 941 1020 1090 1160 1296 1400 1500 1590 1800 1860 2000 2130 2477 2610 2770 3223 3330 3550 3760 4190 4460 4720 5370 5530 5850 6170 6760 7160 7540 7920 9213 9470 9980 10490 10980 12280 12930 13580 14220 16460 17260 18860 21180
Axis y-y [cm4] 2.34 2.70 3.10 3.57 3.80 4.32 5.56 5.86 6.55 7.32 9.62 9.90 10.93 12.05 13.93 15.07 15.76 17.21 18.77 20.46 22.03 23.89 25.86 27.98 31.15 32.34 34.81 37.43 42.84 45.90 49.11 57.55 59.44 63.34 67.42 75.74 80.44 85.33 97.92 100.8 106.6 112.6 124.6 131.5 138.6 145.9 172.3 176.7 185.7 194.8 204.3 232.4 243.6 255.0 266.6 313.9 327.9 356.7 402.6
Elastic Modulus
Axis x-x [cm3] 18.4 21.0 23.6 27.3 29.0 32.5 39.9 38.6 43.3 47.9 59.8 55.9 62.1 67.8 76.8 74.0 77.7 85.0 92.3 99.6 95.3 105 113 122 123 126 137 148 153 162 175 184 191 206 221 222 239 256 266 274 294 313 313 335 357 379 390 402 428 455 481 476 507 537 568 594 628 700 804
Radius of Gyration
Warping Constant
Torsional Constant
Axis y-y [cm3]
Axis x-x [cm]
Axis y-y [cm]
H* [cm6(x103)]
J [cm4]
4.42 4.82 5.17 6.16 6.44 6.86 7.94 9.16 9.63 10.3 11.9 13.4 14.2 14.9 16.2 18.4 18.8 19.8 20.9 21.8 24.2 25.7 26.9 28.0 31.5 32.3 33.8 35.3 40.0 41.7 43.5 49.6 50.8 53.2 55.3 61.1 63.8 66.1 73.6 75.2 78.6 81.0 88.4 92.0 94.9 98.6 112 115 119 123 127 140 145 150 155 175 181 193 209
3.78 3.75 3.74 4.41 4.41 4.39 4.36 5.05 5.04 5.02 5.00 5.68 5.67 5.65 5.63 6.32 6.31 6.31 6.28 6.26 6.95 6.95 6.93 6.90 7.60 7.58 7.57 7.56 8.28 8.21 8.19 8.84 8.84 8.83 8.81 9.47 9.47 9.45 10.10 10.10 10.10 10.09 10.72 10.73 10.73 10.71 11.66 11.66 11.67 11.67 11.66 12.60 12.60 12.61 12.61 13.55 13.54 13.53 13.57
0.50 0.51 0.51 0.55 0.55 0.56 0.58 0.63 0.64 0.64 0.66 0.72 0.73 0.73 0.74 0.82 0.82 0.82 0.82 0.83 0.91 0 .91 0 .91 0.92 1 .00 1.00 1.00 1.00 1.09 1.09 1.09 1.18 1.18 1.18 1.18 1.27 1.27 1.27 1.36 1.36 1.36 1.36 1.46 1.45 1.45 1.45 1.59 1.59 1.59 1.59 1.59 1.73 1.73 1.73 1.73 1.87 1.87 1.86 1.87
0.242 0.251 0.263 0.504 0.508 0.528 0.575 1.12 1.16 1.20 1.31 2.45 2.51 2.58 2.71 4.67 4.72 4.83 4.93 5.09 8.64 8.80 8.98 9.18 14.8 14.9 15.3 15.6 24.7 25.0 25.4 39.0 39.2 40.1 41.0 59.9 60.5 61.8 89.9 90.3 91.2 92.3 131 132 133 135 221 221 223 225 227 357 359 362 364 557 562 576 570
1.595 2.100 2.773 2.383 2.708 3.501 5.752 3.681 4.600 5.763 9.936 6.352 7.686 9.328 12.44 9.129 9.924 11.70 14.00 16.65 13.24 15.31 17.81 20.76 18.16 19.37 22.46 25.73 25.03 28.09 31.68 33.05 34.80 39.19 44.25 43.25 47.55 53.06 56.02 58.45 63.86 70.06 71.17 77.02 83.00 91.30 97.66 100.7 108.1 116.6 126.0 131.0 139.3 148.7 159.6 176.6 187.9 215.6 252.6
Technical data
Tolerances & Steel Specifications Tolerances (In accordance with BS EN 10067:1997)
1. Dimensional Variation - All Dimensions in mm Width b
Thickness t
Ove r
Up to
Pe rmit ted Var iat ion
From
Up to
Permit ted Va riation
-
120
±1.5
-
8
+ 0.7 - 0.3
120
180
±2.0
7
11
+ 1.0 - 0.3
180
300
±3.0
9
13
+ 1.0 - 0.4
300
430
±4.0
12
20
+ 1.2 - 0.4
Improved tolerances may be available by agreement
Radius of curvature of corners r1 for thicknesses Over Up to Max. -
5
1.5
5
9
2.0
9
13
3.0
13
20
4.0
2. Weight Variation The weights shown in the tables have been calculated from the cross section with a density of 0.785 kilogram per square centimetre per metre run. Permitted weight variations: +6.0% - 2.0% of the total weight for consignments of 5 tonnes and over. +8.0% - 2.7% of the total weight for consignments under 5 tonnes.
3. Straightness Variation in Accordance with BS EN 10067: 1997 Straightness tolerance q shall be 0.0035 L (the entire length of the bar) Improved straightness tolerances may be available by agreement
Steel specifications
1. Shipbuilding Classification Society
A
B
D
A32/36*
D32/36*
Lloyds
F
F
F
F
F
DNV
F
F
O
F
F
ABS
F
F
F
F
F
BV
F
F
F
F
F
GL
F
F
F
F
F
Class NK
F
F
F
F
F
RINA
F
F
F
F
F
D40
F**
F = Full approval O = Approval obtained on an order by order basis * = Equivalent to AH32/36 and DH 32/36 for Lloyds Register. Equivalent to KA 32/36 and KD 32/36 for class NK. ** up to 12m m th ickness
2. Construction Bulb flats are available in a range of steel grades suitable for bridge construction in accordance with BS EN 10025: 1993 and BS EN 10113-3 S420M (upto 12mm thickness)
www.corus-specialprofiles.com Care has been taken to ensure that this information is accurate, but Corus Group plc, including its subsidiaries, does not accept responsibility or liability for errors or information which is found to be misleading.
Designed and produced by Orchard Corporate Ltd. Copyright Corus 2002
Corus Special Profiles PO Box 1 Skinningrove Saltburn TS13 4ET United Kingdom T +44 (0) 1287 640212 F +44 (0) 1287 593071
