Category: Hydraulic Structure

5 Component Parts Of A Bridge

The component parts of a bridge can be broadly categorized as follows:

a) Superstructure
b) Substructure

a) Superstructure

The upper part of a bridge consisting of a structural system in the form of beams, girders, arches, suspension cable & truss etc. is called superstructure. The function of the superstructure is to provide carriageway over which the traffic moves with safety.

b) Substructure

The lower part of a bridge consisting of a structural system in the form of abutments, piers etc. along with their foundation, which supports the superstructure is called substructure. The function of the substructure is to support the superstructure. The substructure of a bridge consists of the following 5 components parts:

1. Approaches

The portions of roadway or railway on both the ends of a bridge are known as approaches. It is provided to enable the vehicle running on roadway or railway at a normal level to approach the bridge floor level.

2. Abutments

The end supports of bridge superstructure are called abutments. Abutments are provided to support the superstructure and to retain the earth pressure on their back.

3. Wing walls

The walls constructed on both sides of abutments to retain the earth of drainage bank and approaches, are called wing walls. Wing walls are provided to protect the drainage bank from erosion.

4. Piers

The intermediate supports of a bridge superstructure are known as piers. Piers are provided when the length of the bridge is more. The functions of piers are:

To take and transfer the load from superstructure to the sub-soil through the foundation.
To divide the length of the bridge into suitable number of spans.

5. Foundation

The lower most part of the bridge substructure is called foundation. The function of the foundation is to transfer the load from superstructure to the sub-soil through the foundation.

5 Major Difference Between Bridge And Culvert

Comparison Between Conservancy System & Water Carriage System

What is Mud Pumping

What is Mud Pumping?

Joints form the break in the cement concrete pavement. This causes infiltration of water through them. The infiltration of water through the joints damages the soil sub-grade and the soil slurry ejects out through the joints under heavy wheel loads. This phenomenon is known as mud pumping.

5 Major Difference Between Bridge And Culvert

Difference Between Bridge And Culvert

5 Component Parts of a Bridge

Comparison Between Conservancy System and Water Carriage System

Conservancy System

1. This system does not permit compact design of buildings.

2. This system is non-hygienic.

3. A large area is required for treatment and disposal.

4. Labour force required is much more

5. There are chances for the out break of epidemic.

6. Underground sources of water may be polluted.

7. It requires a small quantity of water.

8. It is cheap in initial cost.

9. No skilled labor and technical persons are required for the maintenance of this system.

10. This system is considered suitable for rural and undeveloped areas.

Water Carriage System

1. This system permits compact design of buildings.

2. This system is hygienic.

3. Less area is required for treatment and disposal.

4. Only a few labours are required.

5. The risk of outbreak of epidemic is greatly reduced.

6. There are no chances of nuisance on the streets.

7. It requires a large quantity of water.

8. The initial cost is very high.

9. Highly skilled labour and technical persons are required for the maintenance of this system.

10. This system is considered suitable for urban area.

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Water Carriage System

Spillway

12 Factors Considering Selection of Site For a Bridge & Culvert construction

Factors considering Selection of Site For a Bridge & Culvert Construction

The selection of a site for bridges and culverts is an art and requires considerable investigation. A few points that deserve attention are given below.

1. A site which is on a straight reach of the drainage should be selected. The curved reach of drainage should be avoided as far as possible.

2. The stream at bridge side should have permanent, firm, straight and high banks.

3. The stream at the Bridge site should be well defined and as narrow as possible.

4. The site should be sufficiently away from the confluence point.

5. There should be no scouring and silting of the stream at the bridge site.

6. A site which offers a square crossing should be selected as far as possible.

7. The site which offers more advantageous foundation condition should be preferred.

8. A site which is sufficiently away from the landslides and subsidence should be preferred.

9. The site should not interfere adversely with any other bridges, weirs, regulators, dams, etc in the vicinity.

10. There should be a minimum obstruction to natural waterway at the bridge site.

11. The stream at the bridge site should be free from costly river training works.

12. The bridge should provide proximity to the direct alignment of the communication route to be served.

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Spillway

Difference Between Bridge and Culvert

Under-Sluices And Their Function

What are Under-Sluices or Scouring Sluices?

The under-Sluices are the openings which are fully controlled by gates, provided in weir wall with their crest at a low level. They are located on the same side as the off-taking canal.

Under sluices are also called scouring sluices because they help in removing the silt near the head regulators.

Functions of Under-Sluices

i) Preserve a clear and defined river channel approaching the regulator.

ii) Control the silt entry into the canal.

iii) Pass the low floods without dropping the shutter of the main weir.

iv) Provide greater waterways for floods, thus lowering the flood level.

v) They scour the silt deposited on the river bed above the approach channel.

Design Consideration of Under-Sluices

The silt of the under-sluice pocket is kept at or slightly above the deepest river bed and about 0.9 to 1.8 m below silt of the canal head regulator.

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Functions Of Diversion Headwork

Chute Spillway Definition/About Chute Spillway

What is Chute Spillway

The chute spillway is also known as the “through spillway”. A chute spillway consists of an open channel, by which water is conveyed from the reservoir to the river or to Nalla below the dam, through a fairly steep slope.

The chute spillway is the simplest type of spillway which can be easily provided independently and at low costs. It is lighter and adaptable to any type of foundation and hence provided easily on earth and rockfill dams.

A chute spillway is sometimes known as a waste weir. If it is constructed in continuation to the dam at one end, it may be called a flank weir. If it is constructed in a natural saddle on a bank of the river separated from the main dam by a high rigid, it is called a saddle weir.

Definition Of Cross Drainage Work

The canal may have to cross the natural drainage like rivers, streams, etc. at different points within the command area.

To dispose of canal and drainage water safely, we need to construct a structure at the crossing point.

A cross-drainage work is a structure that is constructed at the crossing of a canal and a natural drain, to dispose of drainage water without interrupting the continuous canal supplies.

Divide Wall And Their Function

What is Divide Wall?

The divide wall is masonry or a concrete wall constructed at a right angle to the axis of the weir and separates the weir proper from the under sluices.

The top width of the divide wall is about 1.5 to 2.5 m. These walls are founded on wells closely spaced beyond the pucca floor up to the end. the wells are taken well below the deepest possible scour.

Functions of Divide Wall

The main functions served by the divide wall are:

1. It separates the under sluices from the weir proper since the crest level of the under sluices is lower than that of the weir proper, the two must be separated and this is being done by the divided wall.

2. It helps in providing a comparatively less turbulent pocket near the canal head regulator, resulting in deposition of silt in this pocket and thus to help in the entry of silt-free water into the canal.

Read More:

Diversion Headwork

Definition Of Barrage And Their Advantages and Disadvantages

Definition Of Barrage

A barrage is an artificial barrier across the river to prevent flooding, aid irrigation, navigation, or generate electricity by tidal power.

Advantages of Barrage

1. The barrage has good control over the river during the flood. The outflow can be easily regulated by gates.

2. There is good control over silt entry into the canal.
3. A roadway can be conveniently provided over the structure at a little additional cost.

Disadvantages of Barrage

1. The initial cost of the barrage is quite high.

Bridge	Culvert

Large bridges are generally made of R.C.C. steel, pre-stressed concrete.	The Bridge has a total span up to 6m is called culvert.
All bridges are not culverts.	All culverts are bridges.
It is constructed where a drain or depression of any width crosses the roadway or railway.	It is constructed where a small drain or depression crosses the roadway or railway.
It may consist of the elaborate superstructure.	It consists of a minor structure.
Culverts are generally made of brick or stone masonry, plain or reinforced concrete, and Hume pipe.	Culverts are generally made of brick or stone masonry, plain or reinforced concrete, Hume pipe.