1 Bread Street, London, EC4M 9BE
Bow Bells House Headline Facts:
120 natural stone faced panels, covering 1,280 square meters.
Contractor: Bovis Lend Lease
Architect : David Walker & Associates and HOK International
1 Bread Street, London, EC4M 9BE
120 natural stone faced panels, covering 1,280 square meters.
Contractor: Bovis Lend Lease
Architect : David Walker & Associates and HOK International
Blackfriar’s Road, London
600 reconstructed stone panels, covering 5,600 square meters.
Contractor : McAleer & Rushe
Architect : Consarc
Athlete’s Village No. 15, 20 Victory Parade, East Village, London E15 2ER
1,426 reconstructed stone panels, covering 13,651 square meters.
Contractor : Lendlease
Architects : Glenn Howells & Niall McLoughlin
Athlete’s Village No.7, 20 Victory Parade, East Village, London E15 2ER
1,438 brick faced and reconstructed stone panels, covering 15,804 square meters.
Contractor : Lendlease
Architect : Glenn Howells & Panter Hudspith
Athlete’s Village No. 1, 20 Victory Parade, East Village, London E15 2ER
770 reconstructed stone panels, covering 7,400 square meters.
Contractor : Lendlease
Architect : Denton Corker Marshall
Victoria and Albert Museum, 1 Riverside Esplanade, Dundee DD1 4EZ
2,400 reconstructed stone panels, covering 8,787 square meters.
Contractor : BAM
Architect : Kengo Kuma & Associates
Situated on the River Tay, the Victoria & Albert Museum of Design Dundee (V&A Dundee) is the first V&A to be built outside London. The striking structure was designed by Kengo Kuma with BAM as the main contractor. It enjoys the enviable position as neighbour to the RSS Discovery which transported Shackleton and Scott on the Discovery Expedition to the Antarctic in 1901.
The design of the façade drew inspiration from the Scottish cliffs and the silhouette of the impressive façade imitates the shape of a ship at dock. Due to the complex geometric slopes and curvatures, coupled with its exposure to the Scottish weather and its proximity to the North Sea marine environment, architectural concrete was the favoured material option for this project.
Techrete started design work on the £5.6million package of precast planks, which underwrite the design intent, in June 2015. BIM was utilised during this stage for the planks but more interestingly and innovatively it was used to accurately locate where the cast-in channels were to be placed in the walls to facilitate the precast fixings. A GPS system of precise co-ordinates was developed to ensure total accuracy of the interface between the cast-in channels and fixings on the panels during the installation process. There were approximately 18,000 channels cast in total. Pioneering bespoke fixings were also engineered by Techrete which contributed to the overall speed of installation. These fixings were specially designed with marine grade materials to ensure there would be no corrosion due to its maritime location.
Due to the complexity of the curvature and complex geometric slopes of the façade mentioned previously, the manufacture of the moulds, in itself, presented some challenges. From a distance, the planks look almost uniform, with a slightly non-linear appearance. However, whilst the planks from the anterior aspect are a comparable size, the posterior of the planks are differing sizes and orientations. The traditional mould manufacture process to facilitate such diversity in the planks, would have proved very costly with a lot of wastage so Techrete experimented during the mock up phase and initially toyed with the idea of devising a hydraulic driven adjustable mould. This method was examined and it was deemed economically prohibitive. Through an advanced design process and collaboration with a steel mould builder, a rotating steel mould was devised that enabled the mould to rotate on large rollers and had the capability to lock the form at given angles which were required for the diversity at the posterior of the units. The fully adjustable steel moulds facilitated quick and easy mould changes, were simple to operate and adjust and eliminated the need for a high volume of moulds thus reducing waste and improving quality.
Careful consideration went into the choice of design mix. With such a detailed design brief for this structure, Techrete worked very closely at design stage to agree a mix that would encompass all the elements detailed. The chosen mix was a C155 in an exposed finish. This mix encompasses all the design elements one would expect and draws heavily on the design intent to reflect the Scottish cliffs. The mix consists of reconstituted granite which drew direct inspiration from the rugged Scottish landscape and it was further decided to enhance this mix by exposing the aggregates with the use of a retarder during the production stage. This was effect was further heightened with a light power washing to further expose the aggregates. The overall effect is a striking contemporary structure with all the ruggedness traditionally associated with the highlands of Scotland.
The manufacturing period, which occupied approximately 15% of the production capacity, commenced in August 2016 and the duration was a year. Two months of preparatory site works were undertaken to ensure a seamless installation of the 8,787 linear meters of planks, ranging in weight from 0.9 tonnes up to 2.8 tonnes. The site works, and previously mentioned GPS system facilitated a high level of accuracy when installing the panels. The programme was initially designed to install all planks in a 36 week period but due to the innovative GPS system of placing fixings, coupled with the preparatory site works, and pioneering fixings, this was reduced to 28 weeks whilst on occasions installing up to 22 planks per day which in turn reduced the overall programme for the project. Higher level planks were installed using mobile cranes but those on the lower levels, due to their underslung nature, had to be installed with a specialist bespoke lifting equipment designed by Techrete and their specialist lifting equipment supplier. The onsite installation commenced in March 2017 and was complete by the end of October 2017.
The technical innovation displayed during design, production and installation further strengthens and displays the versatility of precast concrete in delivering on design intent that otherwise may be unachievable with other materials and traditional methods of construction.
8-10 Moorgate, London EC2R 6DA
42 Portland stone, brick faced, granite and reconstructed stone panels, covering 590 square meters.
Contractor : Allies & Morrison Architects
Architect : MACE