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Bridges Types

Bridges

The key element of Civil Engineering is Bridges. It is based on the simple principle of load-bearing structure and better known as beams, arches, and suspension bridges.

The different types are:

  1. Beam Bridges,
  2. Arch Bridges,
  3. Suspension Bridges.

Beam Bridges:

Beam Bridge and its details
Beam bridges and its detail with benefits
These are the bridges constructed by truss or by the beam or cantilevers. The load by the horizontal deck is transmitted to the piers or abutments. The cantilever bridge transmits load through piers central to the beam.

Mainly two types of structures are seen and they are of steel & concrete.
In Steel structure, the deck made of steel and concrete are supported on the settled on steel beams, while in concrete bridges the beam and slab decks are of reinforced concrete.
If the bridge is to span water, barges or pontoons may be used to float material out to the lifting position. A temporary system of trestles may be used as a means of placing the beam and girders. For bridges spanning high drops, plate-girders or trussed-girders may be hauled across the opening using rollers.
Alternatively, cantilever launching may be used, used where the beam is launched from one bank, with sufficient ballast to counteract the overturning force and hauled across the span using a winch.

Arch Bridges:

Arch Bridges and its details
Arch bridges consist of a load-bearing arch in a state of compression, the strength and stability of which allow them to carry greater loads than beam bridges. The arch can support the horizontal deck of the bridge either from above or below.
The constructions method for the arch bridges typically includes:
1) Supporting the arch using trestles until construction is complete. This is suitable for arch bridges 
2) Cantilevering the ribs out from the sides of the span. Suitable for a bridge over high drops that cannot be spanned with trestles.

Suspension Bridges:

Suspension Bridges and its details
Suspension Bridges consist of tower secured by cables that suspend the central structural span or deck. The Tower Foundations may be constructed using caisson or cofferdam techniques, whilst the cable anchorage can be secured through anchorage tunnels to the suitable ground on either end of the bridge.
The anchorage foundations are usually constructed deep into a hill slide on both banks. The tower is typically constructed using steel or in situ concrete, built on large concrete bases. Cables housing generally take the form of massive concrete blocks either positioned in the water at either bank or deep into the bank itself. The deck can be erected either by lifting sections from pontoons below cantilevering sections out from each end.

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