On Saturday 7 February 2015, residential developer St George celebrated a significant milestone in the construction of One Blackfriars with a 24-hour continuous concrete pour.
Once completed in spring 2018, the iconic tower will stand at 50 storeys high and encompass approximately 57,000 tonnes of concrete structure.
At 3,200m3, this is the largest concrete pour ever completed in one sitting by contractor Laing O'Rourke, as the team took delivery of approximately 400 trucks of concrete to the site from factories in Kings Cross and Silvertown.
The newly-formed raft slab will carry the weight of the full concrete structure, distributing the weight evenly across 36 large diameter bearing piles. It is estimated that the concrete will take 56 days to achieve its specified target strength.
The overnight pour - brought forward by a week to avoid disruption to a nearby hotel over the Valentine's Day weekend - filled an excavated hole 18m deep, resulting in a raft slab up to 4.5m thick. This concrete slab will provide stability for the 170m-high tower in the face of wind resistance, creating an internal lever arm across its base and providing a large mass to anchor the form.
The design for this soaring asymmetrical tower has been created by Ian Simpson Architects and features a dynamic double envelope façade with two distinct layers. This double-skin helps fresh air to circulate the building, reducing the need for further cooling systems and giving the building an unusual curved form, adding an impressive new silhouette to the London skyline.
Michael Bryn - Jones , Managing Director, St George South London, said: "We are delighted with the ongoing building progress at One Blackfriars. This vast concrete pour marks a significant milestone in the construction of the tower and it is thrilling to see a record-breaking pour conducted at a St George site. Work will now commence apace and Londoners will be able to watch as One Blackfriars begins to take shape on the city skyline."
Source: St George www.berkeleygroup.co.uk