A Culvert a tunnel carrying a stream or open drain under a road or railway. It is constructed for the flow of water under the structures and sometimes for the facile passage of electrical cables without interfering with roadways and railroads crossing over it.
Read More: Bridge Components and Their Function
What Is A Culvert?
A culvert is a tunnel-like structure that is constructed to allow water to flow under a road, railroad, or similar obstruction to provide cross drainage or to take electrical or other cables from one side to the other. This system is enclosed by soil or ground.
In the case of a highway where a culvert is constructed to cross the small traffic pass on it etc., the culvert length of span may be about 4.5 m. similarly, in the case of a railway track, the maximum length of span can be about 6 m and it should not be greater than this limit.
It is served as a dual due to use both as cross-drains to relieve drainage of ditches which is at the roadside and to pass the traffic such as water which is present under a road in the form of natural drainages and stream crossings.
A culvert may also be a bridge or tunnel-like structure designed to allow water, vehicle, pedestrian traffic to cross over the waterway while allowing adequate passage for the water.
Culvert also acts as a water pipe or sewer that crosses under a road or railway, trail.
Synonyms Of Culvert
Drain, channel, gutter, conduit.
Materials For Culvert Construction
The main materials for culvert construction are as follows;
- Steel. Structural steel plate (SSP) corrugated steel pipe (CSP)
- Aluminum pipes
- Plastic (typically high – density polyethylene (HDPE))
Selection Of Material For Culvert
Selection f material for Culvert is as follows;
- Durability and Cost
- Strength of structure.
- Hydraulic efficiency.
- Local construction practices for installation.
Culverts can be constructed of a variety of materials including cast-in-place (i.e. In some cases culverts are constructed in the site called cast in situ culverts) or precast concrete it may be reinforced or non-reinforced.
A mixture of more than two materials combined to form composite structures. For example, open-bottom corrugated steel structures are generally built upon concrete footings.
Shapes And Sizes Of Culverts
Culverts come in many sizes and shapes are as follows;
- Box-like constructions
Parts of A Culvert
The major culvert parts are as follows;
- Road embankment
- Culvert inlet
- Culvert pipe
- Culvert outlet
- Culvert foundation
Types Of Culvert
Following are the types of culverts generally used in construction,
- Pipe culvert
- Pipe-arch culvert
- Box culvert
- Arch culvert
- Bridge culvert.
- Metal box culvert
1. Pipe Culvert
The culvert having a single in number or multiple pipes are placed side by side over a base of concrete below the embankment of a railway track or roadways by fixing there both ends into masonry walls.
The pipes culvert is made from R.C.C., cast iron, steel, etc.
The pipe culverts are widely used, it is very easy for installation is at a competitive price.
Pipe culverts are available in different shapes such as circular, elliptical, and pipe arch and their shape selection depend on on-site conditions
These culverts may be used of single in number or multiple, if the width of the span or channel is greater, we will go for multiple pipe culverts. Generally, they are used for a larger flow, and an installation of a single pipe culvert, we can use the larger diameter size culvert.
The range of diameter of the pipe culvert is between 1Meter to 6m.
The pipe culvert is chosen for smaller types of drainage works, which pass through the embankment of road or railway.
Pipe Culvert Advantages
The following advantages of pipe culverts,
- The pipe culvert is constructed for any strength by using proper thickness, and reinforcement, mix design.
- Pipe culverts are inexpensive.
- The compressive stresses and tensile stresses can easily withhold that type of culvert.
- The water crosses from under the structure.
2. Pipe Arc Culvert
The pipe-arch culvert is a simple structure that looks like a half-circle-shaped culvert.
It is suitable for larger waterway opening, but the flow should be stable where fishes can be provided with greater hydraulic advantage and they are artistic and it provides low clearance.
It is easier to install and also it is lightweight in nature.
In sites condition, pipe arches are particularly useful where the headroom is limited, and as per the requirement of site condition, that type of culvert can also be provided in multiple numbers.
Such a type of pipe arch culvert is useful to enhance the beautiful appearance.
3. Box Culvert
The culverts are constructed in the form of one or more rectangular or square openings, in their top slabs.
The box culverts made up of concrete specially R.C.C. materials. They used to dispose of rainwater so, these are not useful in dry periods.
This culvert’s construction is preferable, especially in loose soil conditions, and for a larger span and also it requires a good foundation, and not be used for larger velocity.
For a single span of 3 m or for a double span of 6 m width, such type of culverts can be used. The thickness range of the R.C.C slab should be kept within 1.25 to 2.5 m.
There is a sudden change that occurs in the section of bending moment and shearing force due to the sinking of the culvert. Box culvert is a rigid frame and simple construction.
Pressure on the soil is reduced due to the bottom slab of a culvert.
Box culvert is economical due to there is no need to provide a separate foundation and also rigidity.
4. Arc Culvert
The arch culvert involves the construction of a superstructure its superstructure consisting of one or two segmental arches consisting of brick masonry, concrete, stone masonry is commonly used.
The arch culverts are not provided with the piers to the sides of the abutment
Advantages Of Arc Culvert
Following are the advantages of Arc Culvert,
- The arch culvert and artificial floors both are made up of concrete.
- The pipe arch culvert and arch culvert are similar but in the case of an arch culvert, an artificial floor is provided below the arch.
- It is normally used for narrow passages.
- The arch culvert is similar to the Masonry bridges.
- The arch culvert is very easy to install.
- The arch culvert is also made of steel but it is very extortionate.
5. Bridge Culvert
Bridge culvert acts as both bridges as well as a culvert. So, it can be term as a multi-purpose culvert.
Generally, it is rectangular but if the presence of an artificial floor is not important it can be replaced by a box culvert.
It is generally constructed on river and canal hence; it serves a dual purpose.
In the bridge culvert, the foundation is provided under the ground level and pavement is present on top of the culvert series.
The advantages of bridge culvert are to allow traffic to pass on it, it is the most expensive river crossings, very strong, and have a highly strong foundation.
6. Metal Box Culvert
Metal box culvert is an economical alternative to the bridge which is manufactured by using a standard structural plate or deep-corrugated structural plate.
Metal box culvert is very easy to install and it is constructed in a short period.
They have a long service life with greater durability.
Q.1 What Is Culvert?
A culvert is a tunnel-like structure that is constructed to allow water to flow under a road, railroad, or similar obstruction and to take electrical or other cables from one side to the other.
Q.2 What are the types of culvert?
1.Pipe culvert (single or multiple)
2.Pipe-arch culvert (single or multiple)
3.Box culvert (single or multiple)
6.Metal box culvert.
Rushali S. Wankhade who is a civil engineer by profession is also the content writer. I did work as a lecturer in an engineering college, also have an opportunity to serve as a lecturer in an engineering college.
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