Plates

A form of steel widely used in a range of bridge types. Plates may be cut, shaped and welded to offer cost-effective, aesthetic and durable solutions in a variety of applications.

Plates account for about 90% of the steel used in bridges in the UK. The most common forms are fabricated 'I' girders, box girders, and all steel orthotropic decks. Plate girders in the form of multi-beam composite bridges are particularly economic for highway bridge spans ranging from 25m to 100m. Box girders may be used singly or in multiples, and can be economic for highway bridge spans ranging from 45m to 180m. Plate girders and box girders may be used for rail bridges in all span ranges. One of the main advantages of box girders is torsional rigidity, which makes them ideal for curved structures and for construction by launching. Girders may be of either constant depth or varied to suit using haunches or tapers, and girders can be made either straight or curved in plan. All steel decks using plates are frequently used in linkspans and moveable bridges where their light weight reduces requirements for operating machinery and counterweights. Plates are also used to form the orthotropic decks of cable-stay and suspension bridges, where the high strength to weight ratio of steel facilitates spans ranging to 850m and 2000m respectively.

Bridge Type	Schematic	Span range	Use of Plates
Multi-Beam		25 - 100m	Webs and flanges of main girders and diaphragm beams.  Bearing and intermediate stiffeners
Box-Girder		45 - 180m	Webs and flanges of box girders.  Internal stiffeners and diaphragms.
Truss		40 - 500m	Fabricated truss elements, gusset plates etc.
Arch		Up to 500m	Fabricated arch elements.
Cable-Stay		Up to 850m	Webs, flanges, stiffeners and diaphragms for orthotropic decks.  Elements for truss decks.
Suspension		Up to 2000m	Webs, flanges, stiffeners and diaphragms for orthotropic decks. Elements for truss members.

Product Range

Tata Steel have the capability to manufacture plates to British, European and international standards, and have an annual capacity of one million tonnes. Plate sizes are determined by the size and weight of slab used, when rolling from slab to plate the width/thickness ratio determines the plate length. In general, reversing mill plate can be supplied in lengths up to 18.3m and widths up to 3.25m. However, longer lengths may be available by agreement. Alternatively, plate may be cut from coil for gauges up to 20mm and widths up to 2m.

Grades

Steels of 355N/mm² yield strength are predominantly used in bridgeworks applications in the UK because the cost to strength ratio is lower than for other grades. Grades S420 and S460 offer benefits in terms of reduced flange thickness, construction depth and overall weight, but the benefits are reduced in applications which are fatigue critical or where stability governs. Plates may be supplied in the Normalised, Normalised Rolled, or Thermomechanically Rolled condition. Higher grades in the Quenched and Tempered condition are available but are rarely used on bridges.

Additional Services

• Tata Steel also have the facilities to offer the following services: Shot blasting and priming
• Ultrasonic testing
• Edge preparation to strict tolerances
• Profiling to shape
• Laser cutting to tight tolerances
• Slit plate.   

Plate Thickness Range