Piled Structural Raft Foundation Solution

Work Type

Design & Build Foundation Package of our Piled Raft Foundation and Reinforced Concrete flooring system for residential loads.

Client

Foreman Homes

Location

Ranelagh Road, Havant, PO9


Project Overview

Following recently completed work for the client where we installed a cost effective alternative foundation scheme to pile, ground beam and a pre-cast flooring solution Speedeck Foundations were appointed to provide a value engineered scheme for the development at Ranelagh Road.

Our client redeveloped disused land and allotments erecting 79 dwellings consisting of 22no. two bed flats, 4no. two bed houses and 53no. three bed houses.

Site Review

The soils were made ground, Head deposits, over Lewes Nodular chalk formation. However, the profile of the chalk band and strength was variable over proposed construction area.


Solution

Due to variability of the strength of the chalk we commissioned further CPT testing at our cost, to enable us to gain a greater understanding of the soil profile across the whole site, by the use of CPT testing we were able to generate 18no borehole data within one day.

The information generated from the CPT tests were loaded into our finite element software which enabled us to produce concept models for each plot, effectively each plot had its own pile design which enabled us to price the project with a greater understanding of the perceived risks in the ground.

The site was firstly excavated to formation level, which resulted in 275mm reduce level dig from structural slab level, once completed SPEEDECK installed at 50mm deep concrete platform which facilitated our light weight piling rigs and structural raft construction.

Our engineer specified a 225mm reinforced concrete raft fixed into 300mm sectional flight auger (SFA) piles installed with lightweight piling rig working on our 50mm concrete working surface which replaced the requirement for a piling mat completely.

Performance

From installation of our working surfaces we completed 6 no plots within 4 weeks to enable our client to bring forward the initial delivery of timber frames to progress the development.

Phase 1 = 1832m2 over 17 plots of structural foundations installed 3 weeks ahead of programme.

183m2 of piled 225mm reinforced concrete rafts installed per week including underslab drainage and services.

Advantages of our SPEEDECK Foundation

By carrying out further specified site testing we was able to reduce the potential risks over a large variable site. We specified and managed further site investigation works taking away this burden from our client.


ACCREDITATIONS