Ripple effect: Concrete’s softer side is showcased in new projects by Zaha Hadid, Timothy Hatton Architects and Walter Jack Studio.
Zaha Hadid Architects
Designed by Zaha Hadid Architects for bathroom manufacturer Roca, the 1100 square metre Roca London Gallery at Chelsea Harbour includes exhibition areas, a meeting room and multimedia suite. The fluid ‘carved-out’ appearance of the facade and interior spaces is inspired by the movement of water. Linking both the inside and outside materially is the expressive use of glass reinforced concrete.
GRC is a thin section concrete that uses alkali-resistant glass fibres for reinforcement instead of steel. By eschewing the traditional need for reinforcement cover (due to the non-rusting properties of the glass fibres) it is possible to create structures that are both lightweight and strong. As well as providing good levels of compressive strength, GRC’s ability to function in bending means that it is particularly suited to the construction of hollow, lightweight components.
To optimise the manufacturing process, the facade and internal display area was rationalised geometrically and then subdivided into 272 separate GRC panels incorporating straight joints. The panels not only had to be self-supporting, but also conform to transport and handling criteria.
Both the panels and the moulds used to form them were created using 3D modelling techniques – linked to CNC machining – and produced in sequence to ensure full compatibility with each other. The facade is constructed from 36 separate prefabricated GRC panels measuring four metres high by two metres wide, and varying in width from 150mm to 1150mm. Located between the panels are 20mm foam expansion joints. The installation process involved sliding the panels into position and then fixing them at the top and bottom using a Unistrut facade support system. A clear, weather-proof and anti-graffiti coating was used to protect the outer face of the facade.
Designed to accommodate multi-directional structural loads, the 60mm-thick interior GRC panels measure up to 2.2 metres high and comprise a robust honeycomb mesh sandwiched between two waffled concrete layers.
Architect: Zaha Hadid Architects; project team: Zaha Hadid, Patrik Schumacher, Woody Yao, Maha Kutay, Margarita Valova, Gerhild Orthacker, Hannes Schafelner, Jimena Araiza, Mireia Sala Font, Erhan Patat, Yuxi Fu, Michal Treder, Dylan Baker-Rice, Melissa Woolford, Matthew Donkersley, Maria Araya; structure: Buro Happold; m&e, acoustics: Max Fordham Consulting Engineers; qs: Betlinski; construction manager: Empty, SL; client, photos: Roca.
Selected suppliers and subcontractors
GRC Panels: B&T Bau & Technologie; external glazing: Cricursa.
Timothy Hatton Architects
Built at Portobello Dock, Timothy Hatton Architects’ pavilion for this year’s London Design Festival was constructed entirely from Concrete Canvas, a fabric-like material that solidifies on contact with water. Designed with structural engineer Constructure, one of the aims of the project was to explore how Concrete Canvas could be used as a viable building material in areas of humanitarian crisis. According to the Pontypridd-based manufacturer of Concrete Canvas, the concrete-impregnated textile allows up to 150mm of poured concrete to be replaced with just 8mm in a range of applications. This can reduce the carbon footprint of construction projects through material savings, reduced road transport and time spent on site.
Repeating oscillating wave-forms were chosen for the walls and roof of the pavilion for reasons of strength and efficient load distribution. This also allows the envelope to cope with aftershock tremors from earthquakes if required. The modular design comprises five concrete components, which were manufactured on site (using re-useable timber formwork) and assembled without any mechanical fixings, much like Lego. The 5mm-thick canvas was draped over the formers, hydrated, and then removed once set – usually within 12 to 15 hours. Prior to construction, extensive testing was undertaken to determine the most efficient profiles, and how these would interlock on the final design.
The architect suggests that it should be possible to assemble a completely fire-resistant and waterproof building within two or three days without any previous construction experience if light, collapsible formers were supplied with the canvas to site. Other factors that would improve the appearance, speed and efficiency of future designs include using thicker 8mm canvas that has stitched edges and is pre-cut to the required shape.
Architect: Timothy Hatton Architects; project team: Timothy Hatton, Megan Rodger, Alex Turner, Viktor Hagstrom, Tom Hatton, Leonora Hatton; structure: Constructure; contractor: 800 Group.
Selected suppliers and subcontractors
Concrete canvas: Concrete Canvas.
Walter Jack Studio
Located in Redruth, Cornwall, Heatlands is a £35m development aimed at transforming 7.5 hectares of former tin mining land into cultural, community and commercial facilities for local residents and tourists. Currently under construction, Crushed Wall by Walter Jack Studio is a 25-metre-long by three-metre-high concrete retaining wall leading from the village of Pool to the main Heartlands site.
‘Crushed Wall is for me about two things’, says Walter Jack. ‘It is about place and process. Heartlands is geologically very special. Nineteenth-century miners dug an astonishing 1000 metres down through granite to extract tin ore. This is one of the hidden stories Heartlands will celebrate. When the studio was asked to design a retaining wall, the geological connection seemed serendipitous. Retaining walls hold back the geology; they are the boundary between the above-ground world and the world of mining’.
One of the things that interests Jack as a maker is the way that manufactured things are often duller than the processes that bring them into being. ‘Concrete for example, is not usually noted for its fluid softness, although its starts out as a liquid. We wanted our concrete to tell its own story, to retain the ‘liquidness’ of its process’.
The starting point for the detail design was a length of rubber sheet, some plywood and a hired cement mixer in Jack’s back garden. The final shutter was built in one piece using a single sheet of rubber that measured 40 metres long by four metres high and weighed a tonne. At the lower end of the wall, the rubber sheet is crumpled down to a height of 1.5metres. At its highest point the sheet hangs like a curtain.
Once the shape was formed the shutter was carefully cut into six pieces. One of the challenges was to retain continuity of the fluid form between the shutters. After some successful prototyping, the shutters were delivered to Ladds Concrete, which is close to the site. Weighing up to 20 tonnes each, the precast sections of wall were delivered to site and installed with millimetre accuracy. Located between each panel is an 18mm expansion joint, filled with foam core insulation and faced externally with a concrete coloured structural silicone sealant.
Designer: Walter Jack Studio; design team: Walter Jack, Paul Channing, Rowan Mackay; structural engineer: Structural Solutions; concrete consultant: David Bennett; surveyor: Dando Surveying, landscape architect: Cornwall Council; client: Heartlands.
Selected suppliers and subcontractors
Concrete, reinforcement: Ladds Concrete; concrete shutters: Richard Stump, John Hall.
First published in AT223, November 2011