21st century steel bridges
The bridges of today show the advancements in steel technology and design which have occurred over the last century. From the modest spans to the exciting cable stayed and suspension bridges, steel has a wide appeal. Products to meet the needs of the most demanding criteria are now readily available. This section illustrates the scope and versatility that steel can offer architects and engineers for all types of bridge construction.
Multi-beam
Multi-beam steel composite decks are very competitive for highway bridges in the span range of 15 – 100m. They comprise a reinforced concrete deck slab on top of several girders.
Box girder
Box girders are a particular form of plate girder, with two webs joined by common top and bottom flanges. Boxes may be used either singly or in multiples.
Truss bridges
A truss is a triangulated framework of elements that act primarily in tension and compression. It is a light-weight yet very stiff form of construction.
Arch bridges
In the traditional form, a steel arch has a similar structural action to old masonry arch bridges. The arch springs from the foundations and exerts horizontal thrusts on them.
Cable stayed bridges
Cable-stayed bridges are a recent adaptation of the suspension bridge principle. The deck structure is supported by tension stays sloping from one or more towers.
Suspension bridges
The suspension concept dates back to antiquity, and it is because of their fundamental simplicity and economy of structural action that suspension bridges are used for the longest of modern bridge spans.
Moveable bridges
Moveable bridges are frequently used over navigable waterways, where it is either impractical or too expensive to provide a bridge with sufficient vertical clearance over the water to allow the passage of shipping.
