Through the use of DAWSON-WAM’s relatively silent and vibration-free pile installation we can offer a virtually zero tolerance installation when working adjacent to existing buildings and structures. This can be extremely beneficial to clients in maximising space when working within built up environments such as city centre sites.
The Cased CFA systems operates an offset system where the most outer part of the system is the casing which mean piles can be installed extremely close to existing structures. Typically piles can be installed within 100mm of existing structures where Conventional CFA systems are restricted by the drive motor geometry and require at least 600mm clearance.
For a Client’s peace of mind DAWSON-WAM can carry out all pile testing, vibration & noise monitoring, pile deflection analysis and sensitivity analysis of adjacent structures when completing close proximity works.
We have been working with Toorc Consulting Ltd and Soiltech on producing a new piling rig. As you know building basements with CFA piles is normally the most cost effective solution, however being close to boundaries and tree protection orders causes significant problems with clearances such that you have to either reduce the basement size or opt for the sheet piling zero rig which is very expensive (about twice standard sheet piling rates). Normally you need to leave a minimum 750mm from face of obstruction to centreline of pile thus nearest internal basement wall face to an obstruction is 1200mm or so.
We have developed a piling rig that can now install 450mm and 600mm diameter CFA piles to within 15mm of any obstruction such as boundary walls, TPO’s etc, to a depth of 14.5m. Therefore face of basement wall will be circa 650mm from boundary, adding an extra ½ metre to the basement. At this depth of pile most residential basements and basement pools can be accommodated. The rig will be owned and operated by Burras. The motor will not overhang the boundary therefore does not affect party wall awards which is the most common difficulty we face on tight urban sites recently. This is a way of reducing basement costs and maximising footprint on these tight sites.