Pressing is used primarily when there are severe restrictions placed on noise and vibration. This is mostly the case in residential districts, very close to existing buildings and on embankments. In contrast to driving using impact hammers and vibration techniques, the sheet piles are simply forced into the ground using hydraulic pressure. Noise and vibration are therefore kept to a minimum. We distinguish between pressing plant supported from a crane, plant guided by a leader and plant supported on the heads of piles already driven.
In the first method, a crane lifts the pressing plant onto a group of piles which are then pressed into the ground by means of hydraulic cylinders (as the follow picture shows). To do this, the hydraulic cylinders are clamped to each individual sheet pile. At first, the self-weight of the pressing plant and the sheet piles themselves act as the reaction to the pressing force. As the sheet piles are driven further into the ground, it is increasingly the skin friction that provides the reaction. Both U- and Z-sections can be pressed, and the method can also be used to extract sheet piles.
Various benefits of U-sections:
- A wide range of sections forming several series with various geometrical characteristics, allowing a technically and economically optimum choice for each specific project.
- Combination of great profile depth with large flange thickness giving excellent statically properties.
- The symmetrical form of the single element has made these sheets piles particularly convenient for re-use.
- The possibility of assembling and crimping the piles into pairs in the mill improves installation quality and performance.
- Easy fixing of tie-rods and swivelling attachments, even under water.
- Good corrosion resistance, the steel being thickest at the critical corrosion points.
Characteristics of AU sections
A weight reduction of about 10% compared to the 600-mm PU series has been achieved by optimizing the geometric dimensions. The increased width allows faster installation, reduces the amount of coating required, due to the smaller perimeter, and increases water tightness thanks to fewer interlocks per metre of wall. Despite their greater width, the driving energy required for AU piles is no higher, thanks to their smooth and open shape and the patented radii at the web/flange connection.
Characteristics of PU sections
Equipped with reinforced shoulders, the new PU 18, PU 22 and PU 28 are the optimum choice for hard driving conditions and as a profile suitable for multiple re-use.
Characteristics of GU sections
ArcelorMittal’s rolling mill in Dabrowa, Poland, formerly known as ‘Huta Katowice’, produces hot-rolled U-shaped steel sheet piles conforming to the existing European standards. The rolling mill added during the last years new sections to their portfolio: GU 7N, GU 14N, GU 18N and the new GU 22N.
(This article comes from Oriental Sheet Pilling Sdn.Bhd. editor released)