Thus this required the hosting of both man and sheet pile high up from the ground to get the job done. And thsi can be dangerous due to the height involved and difficult too as the person esuring the proper interlocking of the sheet piles has to communicate with the crane operator from a height. Further more it will be virtually impossible to do thsi when there is stong cross winds.

Now a company had come out with an igenious solution. A gadget called the “Universal Sheet Pile Threader” solves all the invconvinience and problem as mentioned above. It is completely safe and require only two men ( one infront and the other behind the sheet pile) to install the gadget and done on ground level (thus very safe)

Watch the video below to see how this gadget work.

Sheet piles can also be installed or driven by drop hammer. The drop hammer can be single acting or double acting ones. They are powered by disel, compressed air, steam or hydraulic. The hammers usually operate with a false leader or piling frame. An example of which is shown in the video below.

In the video, you can see that the person is first checking on the alignment and verticality  of the sheet pile before giving the go ahead. Do note that in the second part of the installation, the installation process produces vibration which cause some crest of sand to flow down ( on the middle right of the video).

And between double acting hammers and single acting hammers, double acting are generally preferred for speed and efficiency, and this type performs well in most types of ground conditions but specifically in sandy and gravelly soils.

But single acting hammers are preferred when heavy driving is required. The heavier weight and slower velocity of the single-acting hammer can transmit a higher energy into driving the piles.

When sheet piles are driven by drop hammers, it is important to protect the heads of sheet piles during installation.

1. Using a vibratory hammer
2. Hydraulic powered drop hammer
3. Diesel power drop hammer
4. Hammering with the bucket of an excavator (Not recommended as this can damage the sheet piles and the excavator bucket)

Starting wiht the vibratory hammer, the sheet piles are first grabbed with the hammer jaws. Once in position, the sheet piles are installed using vibration.

The vibration produced by the vibratory hammer is used to loosen the soil and allowing the installation of the sheet pile through penetration into the ground with it’s own and the hammer’s weight.

The vibratory hammer is usually powered by large electric motors. The vibratory hammer is usually hoisted using a crane. Sammler vibratory hammer can be adapted to an excavator boom.

Below is a video on the installation of sheet piles using a vibratory hammer. The hammer is hoisted using a crane.

Sheet piling consists of a series of panels with interlocking connections driven into the ground with impact or vibratory hammers to form an impermeable barrier. Sheets can be made from a variety of materials such as steel, vinyl, plastic, wood, recast concrete, and fiberglass. It is steel sheet piles that this site will concentrate on. It is in the early 20th century that steel sheet piles to becomes  mainstream, thanks to a German by the name of  Mr Tryggve Larssen .

What are the technology of sheet piles application?

As sheet piles formed an interlocking wall, it’s application can be used in retaining purpose and can be adapted to jobs requirement like : -

* Cofferdams
* Ground Water Diversion/Control
* Barrier for Ground Water Treatment Systems
* Retaining Walls
* Containment Walls
* Flood Protection
* Coastal Protection
* Tunnel Cut and Cover
* Bulkheads and Seawalls
* Weir Walls
* Slope Stabilization
* Baffle Walls

The picture below is an example of a coffer dam. Notice the area enclosed and surrounded by a wall of sheet piles. ( Picture sourced from http://www.nasspa.com/ )

There are many advantages applying the technology of sheet piles . One major advantage is the installation of sheet piles, removed the need for open cut excavation. Open cut excavation required large amount of material to be removed. Using sheet piles, excavation is limited to the exact spot where only excavation is require for work to be done. Thus this minimize waste disposal problems.

The next benefit of applying the technology of sheet piles is the sheet piles are removable once the work is completed. In this sense, the sheet pile is used temporary as a retaining wall while the actual work is done.

Sheet piles can be permanent too as they can be part of the permanent strurtures. As an example, in the construction of basement, the basement wall can be casted with the sheet piles wall. Thus this eliminates the need for exterbal form works for the wall as the sheet piles formed the external form work.

Generally topography and ground water does not hinder the use of sheet piles, thus is is another benefit of applying the technology of sheet piles to construction works with uneven topography and high water table. Finally, using sheet pile, they can be installed to various shape formation required by the designers.

The photo below show the use of temporary sheet piles for retaining purpose, allowing excavation to take place. The excavator at the lower level is excavating down. The orther excavator is installing sheet pile.

Improvement is not only in the manufacturing of the sheet piles but also in the installation techniques. In this post we will touch on the different types of steel sheet piles or the sections as commonly known. I will touch on the installation at a later post.

Nowadays steel sheet piles evolves into other sections forms. Starting from the common U-section, sheet piles now comes in Z-section, Flat or Arch section. Flat or straight-web piles are used to form cellular cofferdams.The other sections are used in a wide variety of situation in civil engineering works.

Regardless of the type of sections, steel sheet piles are mostly hot formed with occasionally some cold rolled. The difference is that cold-formed steel shapes are formed at room temperature, while hot-rolled steel shapes are formed at elevated temperature. From a design point of view, cold-formed steel is much thinner than hot-rolled steel.

As can be seen in the attached diagrams, the dimension of sheet piles are labeled b, h, a and e, except for the flat section sheet piles. They represent the With, Depth, Web Thickness and Flange thickness respectively. In the flat section sheet piles, the width is labeled L and the depth W. The thickness is labeled as e. Theses dimension varies and by doing so sheet piles can have various strength.

U- Section Sheet Piles

A U-section sheet pile is in the form of the letter U, with a deep depth and wide width. The depth becomes twice when interlocked.

Z-Section Sheet Pile

A Z-section sheet piles, looks like a slanted letter Z with equally deep depth when interlocked.

Flat Section Sheet Piles

The flat section sheet piles have neligible depth. Essentially its a flat sheet of steel with interlocking features on both sides.

Arch section sheet Piles

The Arch section sheet piles is a U shape with a shallow depth. The shallow depth resulted in an arch shape section.

Here is a little bit of history of this famous sheet pile. In 1902, Mr Tryggve Larssen, State Chief Engineer at the City of Bremen in Germany, developed the world’s first steel sheet pile, which has U section with riveted interlocks. Thus this how the name of this sheet pile comes about.

Larssen U Section Sheet Pile

The interlocking idea on both sides of the sheet pile came about In 1914. This is still utilized all over the world as the most popular steel sheet pile section.

One of the oldest Larssen U pile is displayed at Giken Kochi Head Office to remind us of the historical background of U steel sheet pile. The picture below is a typical larssen sheet piles stacked together.

The interlocking system mentioned above can be seen from the photo on the left. On both the sides of the sheet piles have U shapes which can be used to interlock to another sheet pile.

The interlocking system creates a water tight and increase the strength the sheet pile structures. Be it cofferdams or earth retaining systems.

Here is a diagram thats show how interlocking is done.

interlocking of sheet piles

Image source :-

Image1 - www.trenchcontrol.ie/Images/pics/larssen1.jpg and

Image2 - www.steelcom.com.au/images/sheet-pile-larssen-u-section-small.jpg

Steel sheet piles are interlocking steel panels driven into the ground to form a wall. The installation of sheet piles can be carried out with impact or vibratory hammers. Sheet piling has been used in the construction industry for years.

Steel sheet piles are used in temporary works such as forming a temporary wall to support excavation in soft or water logged soil for the construction of cofferdams or basement. Steel sheet piles can also be used to form permanent retaining walls especially those used for river bank strengthening and in the construction of jetties. They can also be used to form part of the permanent wall of building basement where they are casted together with the basement concrete wall.

The three common forms of steel sheet pile walls are the Larssen/Larseen, Frodingham and straight web piles. All these have interlocking joints that can formed an effective water seal. Straight web piles are mainly used to form cellular cofferdams. Steel sheet piles can come in various lengths of up to 18m.

Beside steel the sheet can be made from a variety of materials such as vinyl, plastic, wood, recast concrete and, fiberglass. The most recent addition to the sheet pile family is the vinyl sheets. These vinyl sheets, with imperious sealants, have made this a very attractive technology for the cutoff or containment of contaminated groundwater flow in the environmental industry.