What is Steel Sheet Piling
It is used as an earth retention and excavation support. It keeps soil back by using steel sheets that interlock to create a strong barrier. If the wall is excessively long or tall then anchors will need to be added to support the weight of the earth pushing against it. Steel sheet piling has been used to support underground parking garages, basements, foundations, seawalls, etc. Basically they are used in any below grade project requiring a retention wall.
There are many advantages and disadvantages of steel sheet piling. The major steel sheet piling pros and cons are described below.
Advantages of Steel Sheet Piling
The advantages of steel sheet piling construction are as follows.
- Steel sheeting provides resistance during installation stresses. The sheets must be driven into the ground and they have high resistance to the force of being driven down.
- It is extremely light weight and makes it easier to lift and handle.
- Steel sheeting is reusable and recyclable.
- There is a long life for it both above and under water. It only requires light protection to keep it maintained.
- The pile length is easily adaptable and can be welded or bolted to make it work.
- They have stronger joints that can withstand the force of being driven into place.
Disadvantages of Steel Sheet Piling
The main disadvantages of steel sheet pile construction are listed below.
- The sections are rarely able to be used as part of a permanent structure. Permanent sheet piles will stay in the ground and act as a long-lasting retaining structure. Most are used as temporary structures and are used to provide safe access roads or paths for construction projects. They are removed once the project is completed.
- It is extremely difficult to install steel sheeting in soil that is rocky or has large boulders. Many times the sheeting cannot be installed to the required depth.
- Driving the sheets may cause neighborhood disturbance. The vibrations from driving the sheets can make the close properties settle and cause problems.
There are two main techniques for manufacturing sheet piles: hot rolled and cold formed. Hot rolled piles are manufactured at high temperatures and the interlocks tend to be tighter and more durable. Hot rolled piles are larger and are stronger than cold formed piles. Cold formed piles will have looser interlocks and are not recommended for hard driving. Cold formed piles are generally used when low permeability is needed.
Steel Sheet Piling Construction Steps
- First, lay out the sheets in sections to make sure that the piles will interlock correctly.
- Drive each sheet to the depth that has been mapped out.
- Then drive the second sheet that has the interlocks between the first sheet and the second locked sheet.
- Repeat until the wall is completed.
- If the wall requires complex shapes use connector elements to ensure that the integrity of the wall is maintained.
- Vibratory hammers are used for the installation of steel sheet piles. An impact hammer is used if the soil is too dense for the vibratory hammer.
- At sites where vibrations are not recommended the sheets are pushed into place using hydraulics.