Difference Between Box Culvert And Slab Culvert

Box Culvert Vs. Slab Culvert

learn about the difference between box culvert and slab culvert in this article.

What Is Box Culvert?

A culvert having one or more square or rectangular openings, and its floor and top slabs are monolithically constructed with abutments and a pier, is referred to as a box culvert.

box culvert

What Is Slab Culvert?

The culvert, in which the superstructure consists of an RCC slab that carries the bridge floor, is called a slab culvert. It is also known as a bridge culvert.

slab culvert

Now let’s check their differences in detail.


Difference Between Box Culvert & Slab Culvert

Box Culvert Slab Culvert 
Box culvert generally consists of one or more numbers of box tunnels placed side by side. The top serves as the roadway. The slab culvert has its superstructure consisting of a series RCC slab that carries the bridge floor, and a pavement surface is placed on top to provide a road.  
They are four-sided rectangular or square structures, the lower side pressed into the ground below.  In the case of slab culvert, there will be rcc deck slab laid over abutments. They can be can also be three-sided.  
The size of a box culvert for single span is normally 3 m and for double span is 6 m. Slab culverts can be up to a maximum span of 3 m. 
It is usually constructed of precast RCC slabs. Small span box culverts may be constructed of stone slabs, supported on masonry abutments, with brick or stone flooring. In slab culvert, the RCC slab of suitable thickness is provided as simply supported over abutments and piers which are constructed of any suitable type of masonry. 
The velocity of the water flow might be changed due to the bottom slab. Slab culverts do not consist of bottom slabs, so natural water flow is maintained and natural bottom substrata remain unaffected. 
The sharp edges of the box-shaped slabs affect the vehicle speed and restrict them from running at high velocity. Slab culverts do not have sharp corners hence making them suitable for vehicles running at high speed. 
These culverts provide the least interference to traffic during construction. Slab culverts do not allow traffic during construction. Require sufficient time for setting of concrete. 
Earth pressure is the main force in the case of box culverts. IRC Loadings have to be taken into account while designing the slab culvert. 
Standard design: ASTM C 1433 Standard design: ASTM C 1504 
This type of culvert is required for purposes that require artificial flooring. Slab culverts can replace box culverts if no artificial flooring is necessary. 
Box culverts are mainly constructed where the soil is soft and the load has to be distributed over a wider foundation area.  Slab culverts are suitable where the bed of the canal or stream is sufficiently firm.  

Also Read

Types Of Culverts & Their Uses
Difference Between Bridge & Culvert
Types Of Caisson Foundation

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3 thoughts on “Difference Between Box Culvert And Slab Culvert”

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