Sheet piling comes in structural profiled sections that typically interlock and are driven into the ground to create a vertical wall to retain soil; to form a barrier excluding or containing water or contaminants; or to provide a hard edge to eliminate erosion or scour. The benefits of sheet piling made of recycled PVC plastic, rather than traditional materials such as steel, timber or concrete is quite easy to appreciate. When you hear plastic, instantly “long lasting” springs to mind, plus additional kudos points for recycling and therefore helping the environment.
- Environmentally responsible, as it’s made from recycled PVC
- Spark proof
- Not affected by saltwater
- Resistant to rodents and attack by marine borers
- Longevity and no maintenance as it does not rust or rot. Looks great and stays looking great.
- Easy to cut manually – requires no “hot work”
- Light, better for manual handling. MultiLock, our biggest seller, weighs 6.2kgs per metre, which is less than half that of its closest steel counterpart (L8 14.4 kgs/m)
- Can be universally used due to its great water and chemical resistance (acids etc)
Can Plastic Piling really be driven?
With many different pile types, pile drivers and soil conditions, this generic question can yield many answers, often the question is made in comparison with steel sheet piling. The first answer, is always a question, which steel pile vs which plastic pile? It is an unrealistic comparison to compare hot rolled steel piling to cold form trench sheeting; and they are both steel! So comparisons of steel and plastic piling can be hard to make.
Some generic statements that hold true (most of the time) are:
- Tubular plastic piling, such as the advanced range, will install more efficiently than U or Z plastic piles, as they are the most rigid.
- If there are no access or equipment restrictions, more heavy duty plastic sheet piles can be installed better than cheaper alternatives (excludes advanced range). This is simply due to the fact that they provide greater rigidity and can be installed with a larger more powerful pile driver.
- If installing piling by hand (rubber maul, sledge hammer or even post drivers) narrower sheets are easier to install as there is less skin friction. Again with the available choice, thick, narrow sections provide a good balance between rigidity and friction.
- Plastic Piling is mostly installed either by hand or using some form of vibrator. These vibrators can be simple compactor plates, excavator mounted vibrators, Movax Lite ML15, leader mounted vertical stack vibrators or suspended piling vibrators (standard or high frequency fixed or variable movement).
- Piling vibrators (not compactors) enable the use of steel strengtheners called mandrels, these enable plastic piling to be driven faster by increasing the rigidity, clearing obstructions and allowing more down crowd.
- Vibratory driving tends to cause less sheet damage than impact driving. This is especially the case witj air hammer pile drivers, as the high blow rate can generate heat and melt the plastic pile.
- PVC is a type of thermoplastic and so as it warms up, it softens – at relatively low temperatures compared to steel (this is why it can be recycled so efficiently), therefore refusal driving with rapid blow air hammers can cause a lot of top damage.
In terms of cold weather installation, PVC is quite resilient, but as the temperature drops below minus 5°C, care needs to be taken to prevent damage to the piling. A temperature of around minus 10°C is often stated as the limiting temperature for installation. It is advisable to consider thicker plastic piling, such as the Ultra Z11 in very cold working conditions.
In addition to sheet pile installation using a vibrator, impact driving is well established for hard driving conditions, such as dense ground or clay based ground. Impact driving is most commonly used to “back” or finish drive the piles once the vibrator has reached refusal.
There are few impact hammers available for plastic piling, those available includes post drivers and small air hammers. They tend to be small air hammers and their size is limited to the ability of the plastic piles to support the hammer. The smaller the hammer, the smaller the drive force and so these tend only to be used when installing short lengths of plastic piling.
Steel sheet piling in contrast, has a wide array of hydraulic and air powered impact hammers available, as it has the rigidity and strength to support such a large range of hammers. The recent development of the BSP BH120 hydraulic impact hammer opens up new possibilities for plastic piling.
Please note it is not always possible to drive sheet piles at a specific location, in a specific soil type (this holds true as much for steel as for plastic piling). More often the main limiting factor to successful installation is the equipment available (or method) is not powerful enough for the task.
When driving sheet piling into the ground, different soils present different resistances and therefore what works on one site may not necessarily work on another.
With the introduction of the advanced range, particularly the hybrids and king post designs, it is now often possible to install a plastic piled solution in areas previously limited to hand installation or very small equipment. The hybrid and king post system is installed more easily, as there is less skin friction and hence ground resistance, it also does not form a continuous underground wall and so can be used in areas with tree roots etc.
The best installation product we offer is MultiLock, and for a variety of reasons, the pile is exceptionally rigid, and at 500mm wide less prone to twisting and deflectection, as the sheet length increases.
Whilst we do sell a lot of MultiLock on its own in long lengths, as a hybrid with timber and steel; this combination (rigid post and short sheet) makes for a very efficient installation, even in difficult ground conditions or limited pile driving equipment.
With such a wide range of products from a number of manufacturers, there is naturally a degree of cross-over, in that capping or corners for one product may well fit another etc. Likewise, within a range particularly the Ultra U and Ultra Z there will be generic cappings and corners used for all products of a certain size.
As at the time of this publication, we are not able to provide straight three way connectors that allow the line to continue and branch off at 90 degrees. The corner pile for the Premium Ultra U and the MultiPile does offer a choice of 90 degrees or 45 degrees and as such its connector could be used as a three way – but clearly allowing for the 45 degree angle.
Plastic capping provides an excellent way to complete a sheet pile installation. Improving aesthetics, whilst mak- ing it easier for wildlife to cross. The one limitation of plastic piling capping is that it is very rigid and as such is well suited to straight runs, rather than curves.
For curved or meandering designs, we offer plugs for our biggest seller MultiLock.
Soft PVC Fenders
These are new to our range and work well with both pile capping and of course flat frontage products. The soft PVC provides impact resistance to a sheet piled structure as it help dissipate the energy of the impact.
We supply all equipment and our services to both domestic and commercial clients throughout the United Kingdom. For more information and advice about plastic piling for rivers, canals, reservoir, lake, and ponds or maintenance and refurbishment of lakes, ponds, reservoirs and canals, please email firstname.lastname@example.org or call 0800 4725524 or 01206 620111.