THE Truline Modular Plastic Piling
Truline - THE Ultimate Wall System®
THE Ultimate Wall System® offering a structurally superior alternative to corrugated plastic sheet piling, as well as traditional steel sheet piling and concrete seawalls.
Truline Plastic Piling is unique amongst the range in that it consists of a number of modules based around a U shaped box pile. It is also the one that has a slightly lower recycled content, and is imported from the USA. So lead times on this product (if not in stock) will be around 8-10 weeks from order.
The design creates a box pile once interlocked and this can be infilled with gravel or reinforced concrete. This is a very attractive product that has excellent impact resistance due to the double skinned modular construction.
Corrugated, single skin plastic sheet piling has become more popular in water based applications, particularly coastal; due to the lower cost of materials, ease of installation, availability, overall aesthetics and a design life of 50 years (in perfect conditions). However, there are drawbacks to using this design as well.
Now in the UK, we are unlikely to experience the extremes of temperature that is encountered in other parts of the world. That stated products designed to endure in very harsh conditions, provide more confidence in their use in the UK.
A major advantage of the double skin concrete filled Truline over conventional single corrugated vinyl sheet piling material is that it offer superior durability against ice push and as a hybrid of plastic and concrete offers overall better endurance during cold weather.
Another advantage over single corrugated vinyl seawalls is that a common installation requires the use of wooden poles or pilings as well as horizontal wooden beams, commonly referred to as ‘wales’, to be constructed on the face of the wall in order to provide support and additional strength. Unfortunately, this opens the door for ice to cause even more damage since it is common for ice to freeze along the corrugations. This allows the ice a way to “grip” the wall and pull it horizontally, often pulling the corrugated vinyl sheet piling completely out of the ground.
On bodies of water where higher winds are common, the ice will crack, shift and begin to stack up against the seawall. After time, the ice will collect under these horizontal wooden beams/wales on the face of the wall and literally lift the sheet piling out of the ground.
In some respects this innovative range of advanced plastic sheet piles blurs the boundaries between sheet piling and formwork.
Certain accessory items are available for positioning the steel reinforcement, as shown above. Truline also offer a JETFilter option, as shown below.
Truline hybrid plastic sheet piling
1) Provides the strength of steel-reinforced concrete
2) Offers the longevity and protection of a synthetic PVC plastic like that of vinyl sheet piling
3) Penetrates the ground to prevent the loss of soil from behind the wall
4) Is light and easy to install
5) Has a flat face profile and not corrugated
6) Does not require the use of front poles/piling and horizontal beams/wale
Truline Specifications
Please click the image below to view and save.
Colour options are shown above, our UK stock is in the light grey.
Problems solving Plastic Piling
The montage below shows a very interesting project where Truline Vinyl sheet piling was used in a horizontal direction rather than the normal vertical direction. The problem solved in this project was the inability to handle concrete infill panels, which would normally be crane lifted into position between to king post H beams. On this scheme, there simply wasn’t space for a crane.
By switching to Truline this retaining wall was constructed without the need of a crane. The front of the retaining wall was then “clad” with a brick wall that suited the local aesthetics better.
This scheme also used JETFilter weep hole drainage filters.
Truline dam structure
The scheme below was one of our first in the UK, Truline forming the wall of a dam structure for a hydroelectric scheme, The site was up a mountain, with only 3ft of peat soil before they hit rock.
Using Truline enabled the plastic piling to be fixed to the rock, with rebar and concrete.
The modular nature of the product enabled the customer to add Truline components to the sluice structure, as such the sluice interlocked with the Truline wall.
Installation options for seawall & bulkhead construction
There are typically two installation options for most seawalls or retaining walls. Most walls are either anchored or cantilevered (no anchor). The Truline system, however, is unique because it can be pin piled into rocky soil conditions.
This unique benefit of the Truline system helps engineers and contractors when installing a wall. Every job site is different and the soil conditions can vary during installation. Therefore, it is very helpful during the installation of any wall, to be able to pin pile individual sections in difficult or rocky soil conditions.
What does “pin pile” mean? Essentially, a steel pipe is installed in the middle of the Truline vinyl sheet pile form and driven into the rock, per the engineer’s design. Walls that are not pin piled can end up “toeing out” at the bottom of the wall, which leads to failure.
Anchor Installation
When conditions allow the sheet to be installed to the required depth for a stable wall.
Use any tie rods and deadman or anchor systems.
Walers can be used in place of or in addition to a structural top cap.
Cantilever Installation
When conditions allow the sheet to be installed to the required depth for a stable wall.
Required embedment depths are deeper than needed for an anchored wall of the same height.
Due to the stresses being much higher than for an anchored wall, the range of exposure height is also limited compared to the possible exposures of anchored walls using the Truline system.
Pin Pile Installation
When conditions PREVENT the sheet to be installed to the required depth for a stable wall.
Truline is first driven to refusal. A pin pile is then driven into the rock, extending below the toe of the sheet and up into the hollow of the Truline form.
Drawings for Seawalls and Bulkheads
Click on the image on the right to view and download a series of drawings that show how to install the first pile, male return wall, round or square corners and expansion joints.
The drawings below provide generic construction examples for seawalls, bulkhead walls and retaining walls. Truline and THE Plastic Piling Company do not provide any warranty that these designs are acceptable for any specific applications. The design must be evaluated and approved by a qualified engineer familiar with the conditions on the actual job site.
Capping options for Truline Plastic Piling
As this product is commonly filled with concrete, it is traditionally finished off with a concrete cap. The formwork needed for such is much more basic than that commonly used in steel sheet piling, due primarily to the flat front and back of the pile, as opposed to fitting formwork around a corrugation.
Alternatively, steel capping has been used, and within our range we have two plastic capping beams that will fit the profile.
Soil plug behaviour – inside the Truline plastic pile
Truline is an open ended hollow pile. initially, as the sheet is installed, it is driven through the soil such that the spoil level inside the sheet remains at the same elevation as the mud line outside the sheet. However shaft friction between the sheet and the soil inside gradually increases as the embedment depth increases. Eventually these frictional forces along with the inertial forces of the soil inside the sheet exceed the bearing capacity of the soil at the pile toe. At that point, the soil plug that has developed is driven down with the pile such that the soil level inside the sheet gets driven to lower elevations than the mud line outside the sheet.
The effect has been observed across a wide range of installations. Its extent varies with soil type making a precise determination of drop in the plug difficult to predict.
It may not be necessary to remove the soil plug at the bottom of the Truline cell prior to filling with reinforced concrete. The soil plug is considered to be sufficiently compacted by the installation process to be stable over the life of the structure. However an engineering analysis must be performed to ensure that the bending and shear loads applied to the wall below the level of the concrete fill ends do not exceed the allowable limits for the Truline pile alone. If either limit is exceeded, a portion of the plug must be removed to extend the depth of the concrete fill to a level below which the Truline Sheet alone can carry the applied load.