FOUNDATION CONSTRUCTION TECHNIQUES
Steel sheet piling
Sterk specialises in the installation of sheet piling. Sheet-piling constructions are used for many structural applications. These can include quay walls, bank or shore protection and walls for construction pits and pressure pits. We have installed sheet piling of up to as much as 36 metres in length! We install complete construction site foundation pits, including anchoring or struts and pile-driving if necessary. We work in inner-city areas, rural areas, on large-scale and smaller-scale projects and in confined spaces or in places where access is difficult. Our expertise centres on sheet piling, but this has made us true all-rounders in that field.
Vibratory sheet piling: minimum vibrations
When it comes to installing sheet piling through vibration, Sterk exclusively employs high-frequency vibratory hammers with variable moment technology. This low-vibration method is fast-working and in many cases can be easily implemented in a built-up or inner-city location. If necessary we can combine this with the techniques of water jetting or pre-auguring to further reduce soil resistance or the problem of vibration nuisance in the surrounding area.
Pressing sheet piles: vibration-free
Pressing steel sheet piling into the ground also enables us to install it entirely without any vibration. To achieve this, Sterk employs cranes with fixed leaders. The largest one can, depending on the circumstances, press piles up to 25 m. We also have a specially built sheet pile extractor which allows us to extract double pile planks. It also makes it possible to extract pile planks from very tight spaces, e.g. once the construction of a building has been completed.
Pile-driving, vibratory or vibratory-free installation of tubular piles
With our wide selection of vibratory and pile-driving equipment we are able to install tube piles with a wide range of diameters and lengths. As of late we can also install tubular piles with a vibration-free technique. We have considerable experience in the installation of fender walls from the water. One such example of this is the is Spaarndam lock and, more recently, the Johan Friso Lock in Harlingen.
Installation of combination walls
Tube piles and sheet piles can be combined into combination walls. The tubular piles provide increased strength and rigidity when compared with a situation in which only sheet piling is used. Such walls are often used as quays or wharves in a harbor. Installing sheet piles without vibrations (by means of static pressure) is something we’ve been doing for a while. More recently we’ve also started to install steel tubular piles vibration-free. This means we can now install complete combination walls without harmful vibrations. Added benefit: we can do both with a single crane!
Driving Concrete piles
Where concrete piles are concerned, Sterk has truly earned the title of specialist in the heavy hoisting sector. Piles with large diameters (up to 600mm) and extensive lengths (30 metres) present no problems for us. Even when the work has to be carried out from the water. The following project is an example of this: Berlagen bridge in Groningen. We have various piledriving rigs available for this type of work.
We specialise in removing old foundations, for example involving the removal of wooden or concrete piles and sheet-piling along banks. The extraction of old piles is one of Sterk’s particular specialisations. We have a wide range of pile extractors which allow us to extract piles of any diameter. If we don’t have the right pile extractor, we will construct one! An example of this is the Kaiserschleuse project in Bremerhaven, where we extracted no fewer than 6,000 piles from the ground.
Sterk offers complete construction site pits, including anchoring. In a number of projects we have also driven in steel anchor piles to lengths of up to 65 metres. A good example of this is the Kaiserschleuse in Bremerhaven.
Auxiliary works include such structures as auxiliary bridges and temporary bridges. Drachten contains Sterk Metaal’s large, modern welding plant where our welders are able to prefabricate component parts up to some 40 metres in size. A great amount of time is saved at the worksite itself by prefabricating as much material as possible.
Fluid injection and pre-augering
Fluid injection (also referred to as water-jetting) and pre-augering are techniques that Sterk employs to minimise soil resistance and thus make it easier to install sheet piling by means of pressure or vibration. In the case of using vibratory means to install sheet piling, another reason for choosing to pre-drill or use fluid injections is to reduce any nuisance caused by vibration.
Diverse and modern machinery
We use a wide range of crawler cranes en hydraulic cranes. Our hydraulic cranes, which are capable of driving in pile plank lengths of up to 20 metres, enable us to construct a pit in no time while causing the minimum of nuisance to the surrounding area. Construction and removal can be completed within 30 minutes. Our wide range of crawler cranes equipped for larger-scale, heavier works, means that we are a jack of all trades. Our participation in large-scale hydraulic works such as aqueducts in Friesland and the entry lock behind Amsterdam central railway station also shows that we are a specialist in the market.
We can develop machines on request for special projects. Sterk has a great deal of experience in this area. For example, we produces a special sheet pile extractor for the Shell in Amsterdam project.