Table of Contents
What is Floodwall?
Floodwall is a concrete structure which is used to resist water from rising and entering into the buildings. These breakwaters help stop water in lakes, rivers, or other waterways when they reach abnormal water levels. Floodwall is also known as Flood Barrier.
Floodwalls are typically constructed as cantilever walls, simple I walls, retaining walls, gravity walls, and sheet pile walls.
Floodwalls are normally built from prefabricated concrete elements. Flood barriers often have locks. A lock is a large opening that allows passage except during high tide when it is closed. Flood barriers are often made up of relatively short elements compared to embankments, so connections between elements are important to prevent flood barrier failure.
Functions of Floodwall
- Provide a barrier against flooding
- Protects enclosed areas and structures from hydrostatic and hydrodynamic loads.
- Keep flood-carried debris away from buildings.
Characteristics of Floodwall
A flood barrier is an engineered structure made of concrete, masonry, or steel to prevent the ingress of flood waters. They are mainly built in urban/industrial areas where space is limited.
Most flood barriers are built away from buildings to avoid structural defects and modifications to the building.
The location and extent of the flood barrier depends on the terrain.
The flood wall surrounding the site has openings to allow access to the site.
Types of Floodwall
1. Gravity Floodwall
These types of walls, based on their name, have the simplest structural design. Using gravity, or actually mass, the wall is weighted to the ground to keep it from moving. Built in the form of a right triangle, the bottom of the wall is much larger and therefore heavier than the top and is buried underground to a certain point. The large underground mass makes it difficult for water to move the flood wall. They are simple in design and concept, but they require a lot of material to build them. The taller the wall is built, the more weight is needed on the ground to balance it.
2. Overhanging Floodwall
This is the most common type of flood barrier used by civil engineers because it is cheap to design and build. They are usually made of reinforced concrete and metal rods. The design looks like an upside down “T”. Buried under the existing slope are the foot and toe of the cantilever wall, with the foot side facing away from the water source. These wall types can also be used as retaining walls. However, like gravity walls, the taller the structure needs to be, the more expensive it will be.
3. Buttresses Floodwall
These walls are similar in design to cantilever walls, except for one lateral wall. The extra wall is also the only thing that separates the two designs. Consists of a lateral support wall on the heel side. A concrete pier is on the opposite side of the backwater. Not commonly used as props take up usable space.
4. Counterfort Floodwall
It consists of horizontal retaining walls on the water retaining side. A bearing wall is hidden under water or soil, thus providing additional space on the other side. Therefore, it is more widely used than retaining walls.
Advantages of Flood Barrier
- It protects the surroundings of the building from flooding.
- Eliminates structural damage to buildings due to water pressure.
- A better option than moving or raising.
Disadvantages of Flood Barriers
- Flood barriers are no solution to large and long-lasting floods.
- Flood barriers can affect local drainage and cause water problems in areas outside the flood barrier. Construction of seawalls may violate state rules and regulations.