What is a wing wall | Types | Purpose

 A wing wall is a structure constructed as an extension of abutments to prevent the earth from coming in contact with a passage provided for passing vehicles, pedestrians, and water.

We can also define it as A wall constructed at both ends of the abutments to prevent Earth banks (embankments) from coming on the road, river, or any passageway. These embankments are provided on both sides of abutments to retain the earth at their position. These retaining walls can be decorative.

These walls are typically made of concrete and are designed to resist the lateral forces of the soil and water that may be pressing against the bridge or retaining wall.

A person standing in front of the wing wall construction

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What is a wing wall in a bridge?

A wing wall is also provided in the bridge structure. The function of wing walls is almost similar in all types of civil engineering structures. This structure keeps the backfill behind the abutment wall. These retaining walls may be separated or a part of abutments.

We can also say it is a side wall of the bridge structure. But it can be built at any angle or may be perpendicular to the abutments of the bridge. Bridge wing wall construction may be of the same material or different. Let's understand it with a figure of a bridge structure.

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Here in the below image, you can see where is wing wall is provided. The center line (dashes line) represents a bridge passageway (maybe a road or river Bridge). A rectangular abutment is provided on both edges bridge. While a wing wall is provided on either side of the abutments. 

This means the walls are constructed on both sides of the constructed abutment.

Wing wall structure figure 

Purpose of Wing Wall

Here the question arises, what is the work of wing walls?

• To protect the earth bank of the river from erosion of the soil
• To support and protect the embankments because they slide due to weathering action
• To retain earth banks stable
• For smooth entry into the bridge site (especially for water flow)

Types of the wing wall

The different types of wing walls are as follows

1. Straight Wing Walls
2. Return Wing Walls
3. Splayed Wing Walls
4. Free Standing/Separate Wing Walls
5. Cantilever WingWall

1. Straight Wing Walls

Straight wing Walls are constructed on the right angle of the Center-line of the bridge and inline of the abutment on a bridge, as shown below picture. These are built on both sides of abutments.

Straight Wing Wall Type

Such walls are suitable for small bridges, railway bridges in cities, and culverts constructed across the drains. Here drains are those which carry low discharges & sometimes remain dry.

2. Return Wing Walls

 It is the third type of wing wall. We called them "return wing walls" because their walls return back of abutments. You can understand it more clearly from the below image.

Return wing wall in bridge

We can also say that return wing walls are perpendicular (90^o degrees) to the abutment. These abutment walls are provided when the difference between abutment and approaches is significant. It is essential to provide these abutment walls where banks are very high and hard. Their top width is 1.5 meters and has vertical faces. These are perpendicular to abutments.

3. Splayed Wing Walls

Splayed Wimg walls are provided with some angle nearly 45^o degrees to the abutment. It is sometimes constructed on an acute angle of less than 90^o. Their top width is about 0.5 meters.

Splayed wing wall type

Such wing wall designs are suitable for small and large bridges on rivers. It is provided where there is a need to reduce the width of the river for providing a bridge or something.

4. Free Standing/Separate Wing Walls

In this type of retaining wall, there is no need for abutments, and walls are independent of the main structure. This may lead to independent settlement of both abutments and wing walls. This type of design is costly for construction.

Selection of type of WingWall for construction

The selection criteria for the type of wing wall to be used depends on various factors, including:

• Site Conditions
• Loads and Forces
• Aesthetics Look
• Cost of construction
• Constructability
• Accessibility
• Durability
• Local regulations
• Environmental impact