Housing Development
The Fairways, St Leonards, Stafford
The St. Leonards development is based on the site of an existing electronics manufacturing and distribution facility. Planning permission was granted for the development of 430 homes, and local retail units up to a size of 575m2. Our estimate included for the design, installation and testing of nearly 5000 columns across 214 plots.
Generally, ground conditions are very poor across the site. Beneath a relatively thin layer of made ground, the site is comprised mainly of soft clays, very loose sand, and silts to depths in excess of 15m. An economic foundation solution was not obvious.
We were approached by the Geotechnical Consultant to consider if vibro was an option for the scheme. As a consequence of the poor ground conditions, we proposed a partial depth solution installing bottom feed vibro stone columns to 8m depths. As the only alternative was conventional piling to significant depths our proposal became the preferred option to the Developer.
Because of the poor ground conditions this solution also needed the approval of the NHBC, the warranty provider for the site. After an initial rejection it took a lot of effort over the course of eight months including numerous phone calls, preparation of design calcs and several meetings, to finally gain approval for our proposal. Upon acceptance the NHBC stipulated that reinforced ring beams were required, though as there was some areas of less poor ground, if an SPT N value >10 was proven at 8m depth beneath a plot then a standard doubly reinforced strip footing could be utilised. Throughout the project, we completed regular plate and dummy tests to NHBC standards, ensuring the quality and performance of the Vibro Stone Column solution.
Alongside our main services, we also offer a setting out service through our sister company Atlas Site Engineering, undertaking all related setting out for the works. Atlas undertakes setting out work across the United Kingdom and can be contracted for additional setting out services including civils and earthworks, ground improvement and piling, and construction setting out.
