Installing screw pile foundations for a noise barrier (CASE: Highway 5, Mikkeli, Finland)
Highway 5 is the main arterial road of Eastern Finland and it’s used for both personal and industrial traffic. At present, 7,800 – 13,300 vehicles travel along the 37 km stretch of the highway between Mikkeli and Juva daily, but the amount of traffic is constantly increasing.
Due to the heavy traffic, in addition to road improvement works, measures have been taken to prevent noise pollution. Rotopile was given the task of installing the screw pile foundations of the highway’s noise barrier, which is situated in the Lähemäki area of Mikkeli.
The main contractor in this project was infrastructure construction company Destia Oy. The noise barrier is 200 meters long and it’s made from insulated, stackable aluminium cassettes. The height of the noise barrier is approximately 3,5 meters, so the foundation had to be especially strong due to the large wind surface area.
Two small screw piles are often more economical than one big one
There are two techniques that are regularly used when installing screw pile foundations for noise barriers:
- One big screw pile directly below the fence line
- Two small screw piles situated on either side of the fence line and connected together with a steel beam
In foundations that use two screw piles, one of the piles is subjected to tensile load and the other one compression. Because of the high tensile and compressive strength of screw piles, sufficient load bearing capacity can be achieved with relatively small piles, which results in more economical material and labour costs.
The two screw pile foundation method was also used in the Highway 5 project. Altogether, we installed approximately 80 screw piles that were 2,5 – 6 meters long. The pile caps were welded on top of the piles, on which steel beams were then installed. Altogether it took four working days to complete the foundations including screw piling, welding and installing the steel beams.
Screw piles from Rotopile have also been used in another, almost identical, noise barrier a couple of kilometres away in Juvantie Road in the Oravinmäki area of Mikkeli. The two pile method has been used in the foundations of both noise barriers in Mikkeli. In connection with the piling work undertaken in Juvantie, the screw piles went through a tensile test to provide assurances of their quality. The Finnish Transport Infrastructure Agency also took part in performing the test.
Screw pile foundations for noise barriers – is it worth it?
Using screw piles as the foundations of noise barriers is supported especially by the savings made in time and overall expense.
The high load bearing capacity of screw piles gives the opportunity to use smaller than usual piles in noise barrier foundations. This leads to reduced overall material costs, easier handling as well as quicker installation.
Light and agile installation machinery also reduces the amount of preparation work required and makes it possible for piling work to be undertaken in difficult locations, for example on earth mounds. Screw piling is suitable for foundations of noise barriers in public areas, highways and railway tracks alike.
Rotopile has extensive experience in sizing and installing screw piles for noise barriers. Do not hesitate to contact us if you’re looking for suitable piles for your noise barrier project.
