It’s an interesting argument amongst Engineers and Building Contractors… Screw Piles or Bored Concrete Piles.
As you’ll guess from our name, East Coast Screw Piers is pro Screw Piles – for a number of reasons:
Screw piles can be used in almost all ground conditions!
We installed piles for a customer who had attempted boring concrete piles where the water table was found at 2m deep. His attempt was a complete failure as the bored hole was collapsing just as quick as he could excavate it. 🙁 It was a mess. We came to site and installed 43 piles between 3 and 4m deep simply and quickly. All the engineers required loads were obtained and the client was able to continue on with pouring the ground slab. Bored concrete piles mess solved!
One of the important things about screw piles is that the load capacities are verified during installation by excavator. Pressure gauge readings can confirm the required load and extensions added to the pile if ground conditions are poor.
Site Costs
Screw piles are suited to sites with poor access. East Coast Screw Piers have large and small excvators and can gain acess through a gap of 1m.
Concrete pump hire is also eliminated for there is no concrete needed for concrete piles. Thus reducing costs.
Against the costs of site preperation with bored piles there is no spoil generated by screw piles. This means a clean site and no offsite spoil so again a lower project cost is achieved.
Also a low noise and low vibration level is a benefit which can be important on some sites. An aditional advantage is a small footprint and as mentioned, a minimum vibration level to adjacent buildings.
Screw piles generate no spoil so in instances where contaminated soils may be encountered, the soils do not come to the ground surface.
Screw piles can be installed inside existing buildings even with low head height. This has further reduced the cost of concrete pumping on different occasions.
Build Immediately After Installation
One important factor of screw piles is that they can be immediately loaded after completion of the installation. There is no waiting on concrete in piles to harden.
Screw piles can be installed in all weather conditions so do not delay site times.
Unlike concrete bored piles, screw piles do not necessitate the need to call out the engineer to inspect the bored holes. Why? We record each screw pile and make a installation sheet of installed pressures. We then issue a structural engineer’s certificate to confirm all piles have achieved the required loading.
Also while on this subject: the risk of leaving exposed bored piles until the engineer can inspect them can be a disaster in heavy rain! We have had a number of jobs over the years where we have been called in so we could install piles in the collapsed bored pier hole.
Plumbing can be made easier with screw piles over normal 300mm, 450mm or 600mm concrete piles, as drainage, pipework and toilet or sink risers are easier to position with only a 76mm steel screw pile.
So as a summary – Screw Piles benefits far outweigh Bored Concrete Piles particularly when it comes to site access, costings, footprint, timeframes and ease of use in different weather conditions.