Apartment Blocks

Granton, Edinburgh

Western Villages sits to the west of Granton Waterfront adjacent to Forthquarter Park and a short walk from the promenade. Work is well underway to deliver around 450 homes including:
• Social rent homes affordable to people on low incomes
• Mid-market rent homes for households on low to middle incomes
• Homes for sale.

At Town and Country Vibro Limited we work with many differing house builders across the UK. The above scheme initially came in as a piled scheme as the residential units were 5-6 story high, and this is generally deemed as being the maximum height of building that can be treated with ground improvement in the form of Vibro Stone Columns. The Main Contractor CCG approached us to look at alternatives.

As with residential properties a general unwritten rule is maximum 4 story, but in this case, we still looked at the development without dismissing the worked based on higher storey buildings. However, at Town and Country Vibro we look at all aspects of the structural elements as well as the ground solution, to assess the feasibility of the development.

The big issue with higher structures on ground improvement is always differential settlement, as a small amount of differential settlement causes significant deflection on the upper levels of the buildings. Town and country Vibro in this instance looked at all implications within the soil profile and designed the stone columns such that any settlement across the building footprint is limited to less than 5mm. Whereas in general schemes differential is limited to 10mm settlement, but this has an implication on every storey that the building goes up.

Therefore, limiting the differential settlements to a tighter specification allows the treatment of higher storey building possible, i.e., the upper height of a building is not a fixed ceiling height, it requires input to a greater design input to design the differential settlements out.

The scheme was carried out very successfully and all the tests carried out were within 1.5mm of each other, when tested to three times working load on the plate tests and one and a half times working load with the dummy foundation tests. All works were completed within the time scale on site due to the extensive work carried out in the office prior to site commencement.