Bridges Structure Components

Beam bridge or Stringer Bridge or Girder bridge: Beam bridges belong to simply supported bridges with horizontal beams and vertical piers. They are also known as stringer bridge or girder bridge.

These type of bridges are generally stretched with two or more spans and resting by abutment or pier at each end. The bridges are built up with RCC, Wood, steel etc. Beam bridges extent less than 80m.

In a beam bridge, the beam has adequate strength to tolerate the load enforced on it. These loads are further delivered to bridge supports and then to earth.

The top edge of the beam includes compression while the loads are enforced on it where the lower section of the beam is expanded and is under tension.

Benefits of Beam bridge: 1. This type of beam can be easily built up and erected., 2. This type of beam is suitable for short distances., 3. Wide distances are spanned by resting beams on piers.

Arch bridge: The arch bridge is normally constructed with stone, concrete or steel.

The shape is curve where the load enforced on the curve is not directly employed straight down rather the loads are transferred along the curve of the arch to the end of supports known as abutments. Abutments bear loads of the whole bridge & it retains the arch in exact location.

The span length of arch bridges is usually up to 250m, and the roadway of the bridge rests on the arch structure.

Also Read: Brief overview of standard components of Bridge

Advantages of Arch Bridge:

1. It can be simply constructed with the locally accessible material.
2. This type of bridge is very stiff and tremendously strong.
3. Arch bridges are constructed with different types of materials like stone, concrete, steel, etc.

Truss Bridge: Truss stands for a framework that comprises of struts (inclined members). These bridges are built up with trusses having several small components structuring triangular trusses. The span length of truss bridge remains among 50m-110m.

Trusses are very stiff, lightweight. They are capable of withstanding heavy loads. Trusses transmit the load from a single point to greater area.

As the load is enforced to the truss bridge, the top edge includes compression and loads are distributed among the angled members to supports and then to earth.

Benefits of Truss Bridge:

1. This type of bridge can be simply erected in the factory and then set up on site.
2. The piers or supports are relatively less with regard to the beam bridge,
3. They are strong and firm and very light on weight.

Suspension bridges: To build up this types of bridges the deck slab is suspended with suspension cables. The roadway is hanged with steel cables which are attached to two towers and fixed with anchors on both ends of the bridge.

While the load is enforced to the suspension bridge, the deck slab contains compression and then passes through the ropes, cables or chains to transmit the compression to the towers. The towers then scatter the compression directly into the earth through anchors.

The supporting cables going parallel to the bridge contain tension forces, and these are attached to anchorages (solid rock or huge concrete blocks to ground the bridge) to disperse the tension force to the ground.

Tensional force transits to the anchorages and into the ground. The span length of Suspension bridge remains among 150m-2000m.

Benefits of Suspension bridge:

1. Strong and lightweight.
2. It comes with long span to cross the river without any difficulty.

Cable-stayed bridge: In this type of bridge, cables are attached directly to the tower in place of suspended cables. Tension is constantly operating on the cables, which are expanded since they are connected with the roadway. There are no anchorages to tolerate the compression and only one tower to bear the compression. The span length of Cable stayed bridge remains among 500m-1000m.

Benefits of Cable-Stayed Bridge:

1. It is very inexpensive as compared to the suspension bridge.
2. It is suitable for medium spans and can be simply constructed by cantilevering out from the tower.

Cantilever bridge: Cantilever bridges are erected in parts and the two free ends are attached with suspended deck. Cantilever bridge contains a span in between 150m-500m.

In this type of bridge, the two free ends of the cantilever bridge are connected with the suspended deck.

When the load is enforced on cantilever bridge, the top supports are susceptible to a tensional force (pulling force), and bottom supports are susceptible to the compression force( pushing force) to keep the bridge to be balanced. As far as the force is balanced, the bridge will stand in steady position.

Benefits of Cantilever Bridge:

1. This type of bridge is suitable when it becomes difficult to arrange the supports at certain positions.
2. Support is necessary only on one side of the cantilever.