Our in-house engineers specified a NHBC compliant 300mm reinforced concrete raft foundation solution for the plot, supported by 300mm diameter CFA (Continuous Flight Auger) piles. This specification provided an optimal solution allowing a continuous reinforced concrete raft without thickenings, minimising localised ground disturbance and the need for extensive excavation.
Concept Design
We simplified the construction process through our design modelling using finite element software, we modelled the structural loads onto the new structural foundation thereby optimising the efficiency of the raft and pile arrangement, whilst also considering the drainage & services routing in relation to our proposed pile arrangement. We installed 1342m2 of piled structural foundations in less than 9 weeks including underslab drainage, inspection chambers and service ducting .
Design Engineering
The site was located in Devon District Council and the development was on the Astra Printing site and former Crown Works premises. The ground consisted of underlying aquifer with PAH contamination of groundwater a potential risk to the site.
A heave analysis was conducted and found that the site was mainly granular, sandy, gravelly, SILT type soils classified as non-plastic soils therefore negating the need for any anti-heave precautions being specified.
Driven piles were not suitable for this project due to the close proximity of existing properties due to the noise and vibration generated through this method of piling.
Construction
By the end of February, installation of our concrete working surface (CWS) was completed, in advance of our piling mobilisation.
Once groundworks team have released sufficient sections, our steel fixers and shuttering carpenters mobilised to site to commence works of the reinforced concrete slab.
Upon completion of site works prior to concrete pouring, our in-house engineers ensure that all testing has been carried out as specified, complete their final inspection/sign-off before offering the works up our client’s team and warranty providers inspections.
We completed our 1st concrete pour in the first week of May. This marked a major milestone in the project, as it enabled a section to be handed over to our client to release follow on works.
This efficient and well-coordinated process demonstrates our commitment to sustainability delivering quality work on time every time, ensuring that each project phase is executed seamlessly and to the highest standards.
CFA Piling work commenced as programmed, upon completion of area “A” our groundworks crews mobilised to commence works on the lift pits and underslab drainage and services, which had been fully co-ordinated with our pile layout in advance to ensure site works were completed timely. Due to the nature of later living apartments they typically have a tight network of drainage and services runs which requires careful, methodical installation.
