Concrete video : Today’s concrete is being precast on major construction sites
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[Visual Signage] Lafarge safety standards are currently being deployed through the Group, worldwide. In some of the sequences in the film, personal safety equipment may not be complete. Today’s concrete is being precast on major construction sites Lafarge
Building the precast bridge in Ductal®, Saint-Pierre-la-Cour, France Mars Hill Bridge, Wapello, USA Glenmore Legsby Footbridge, Alberta, USA
Construction methods evolve, influenced by economic, environmental, community and safety constraints. To remain innovative in taking on these challenges, construction architects and engineers have opted to use precast concrete. This is for good reason, since next generation concrete, such as Ductal®, Lafarge’s ultra high-performance fiber reinforced concrete, enables true architectural wizardry, outstanding works of art, both elegant and aesthetic. [Visual Signage] Inhabited bridge project in Moscow by Marc Mimram, Russia Marc Mimram Architect – Agence Marc Mimram [Interview] I think that today, particularly with the new materials that are available to us, especially Ductal® and ultra-high-strength materials, we are discovering the qualities both of prefabrication and freedom that were not previously available for major structures. [Visual Signage] Precasting of components for the Devil’s Footbridge by Rudy Ricciotti, France [Voiceover] There are new techniques for producing lighter structures, which take their inspiration from the landscape, such as the Devil’s bridge Footbridge, designed by architect Rudy Ricciotti with engineer Romain Ricciotti. Comprising 15 precast voussoirs (arch sections) in pre-stressed Ductal®, the bridge is 70 meters long with a static clearance of 1.80 meters and a platform just 4 centimeters thick;
Romain Ricciotti civil engineer
Each section, known as a voussoir, is precast in a separate mould, so each time we have a voussoir ready for the scaffolding. There is still work to be done on these voussoirs: cables are passed through the inside, the lower parts are tightened and then the upper parts, which compacts the 15 voussoirs to form a girder. It's like a flat archway. So there you have it, the technique of pre-stressing by post-tensioning. There is something traditional about it. What is not so traditional about it is that we can pre-stress this material unbelievably. This is Ductal®. [Voiceover] This new concrete benefits in fact from features implemented, such as flexibility, superior mechanical performance, with even better control and added value in optimal pre-casting conditions. [Visual Signage] Nicolas Roussel Research Manager for concrete, Laboratoire Central des Ponts et Chaussées (Central Civil Engineering Laboratory)
The manufacturing of this concrete is a little bit more delicate. In the pre-casting factory, its benefit is considerable, since we can control manufacturing much more accurately. So, in my opinion, self-placing concrete is going to develop a lot more. [Visual Signage] Hypergreen Concept, by Jacques Ferrier [Voiceover] Such evolution in techniques and materials enables architects to consider dramatically taller structures that are also more ecological and above all more pleasant to live in. Lafarge also worked together with the architect Jacques Ferrier on a tower concept with this in mind. A very high tower that respects the environment: it’s the Hypergreen concept.
Jacques Ferrier Architect – Agence JFA
So the innovation, in terms of structure, the basic innovation of Hypergreen, is to have a structure with concrete on the outside and one that is mainly precast. These really are totally new ideas, to have what we call an “exo-skeleton”, that’s to say a skeleton on the outside of the building. We had conceived this exo-skeleton, cast with post-tensioned crosses fitted together, which would then enable us to consider an entirely precast tower more than 200 meters high. So pre-casting in the case of a tower is an extremely important issue since clearly from the perspective of today’s construction site, one that’s durable and safe, using concrete was somewhat limited by the need to raise the cement and make castings at 150 or 200 meters off the ground. In the Hypergreen project, and in projects on which we have worked since, which started from this prototype, we have indeed proposed precast structures that are more like works of art than buildings, since it’s all about concrete components that are put in place with cables and post-tensioned once they are in position.
An unthinkable concept even 10 years ago, totally satisfying the worldwide society’s requirements, a source of inspiration for the Lafarge Research Centre, which is already working on tomorrow's concrete with one objective in mind: to push back the boundaries of construction in the interests of sustainable development. [Visual Signage] Logo Lafarge Bringing materials to life™ Copyright Lafarge 2009 http://www.lafarge.com Yüklə 21,51 Kb. Dostları ilə paylaş:
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