Basic types of bridge structures
There are many different ways to design a bridge, now let's look at basic types of structures.
Beam is a rigid, usually horizontal, structural element which may itself form an entire simple bridge. Simplest beam bridge is such as a log or a stone across a stream.
Cantilever bridge is a bridge with rigid arms extending from both sides of a base, the inner ones usually supporting central span. A cantilever is a bracket secured at one end with the other end hanging free. The simplest form of cantilever bridge has a central beam supported between opposite cantilevers,
Arch bridge is a bridge with one or more curved structural span.
- Semicircular Arch, Roman arches were semicircular. This structure had important consequences, it was possible for Roman engineers to build their bridges out from the shore a span at a time - cofferdam, then foundations, then pier, then arch - rather than having to go through the much more difficult operation of putting the entire bridge substructure in position first.
- An elliptical arch has the shape of half an ellipse, a semicircular arch can be flattened to make an elliptical arch.
- A segmental arch, its curve is less than semicircular segment of a circle.
- Bowstring arch likes the string of a bow that is being flattened, the ends of the arch are linked to resist outward thrust.
* Chinese arch, some Chinese arch bridges often have remarkably slender crowns of semicircular arches, which soar high above riverbanks, necessitating flights of steps on both sides. Others have many arches , with only those at the centre enlarging to accommodate boat traffic beneath.
Suspension bridge is a bridge with its deck supported from above by large cables or chains hanging from towers.
Cable-stayed bridge is a bridge with a deck supported from towers by straight cables.
A truss bridge is a bridge composed of trusses.Truss bridges are one of the oldest types of modern bridges.
- A king-post truss is a basic feature of medieval timber building. It could be multiplied, extended, inverted or overlapped.
- Burr truss or arch is a combination of an arch and a multiple king post truss design.
- Town lattice truss is a system of timber diagonals with no verticals.
- Long truss resemble a series of giant X's.