7/29/2019 Concrete 2007

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MODERN METHODS OF CONSTRUCTION

Semi-precast solutionA new semi-precast system with twoway spherical hollow void fonning madefrom recycled plastic is quicker and is upto 35% lighter than traditional solidconcrete slab construction.

DANIEL PTACEK, CoBIAXTECHNOLOOIES

I n Britain, steel and wood structures are often chosen overconcrete because they are lighter and considered easier toerect, as well as having less curing and drying time . Manymodem prefabrication techniques are available in steel andwood . In mainland Europe it is quite the opposite.

Precast and semi-precast techniques remove criti calwork from site and reduce tim e and ef fort. Void-formingtechniques lighten the structures . Whe re these structurestruly outperform stee l and wood is in their fire, acoustic ,thermal, and resonance performance, and - if designedwell - appearance.

Traditional c oncrete fram es with simple flat s lab construction are hard to beat for durability, therm al mass,reduced inter faces and being free of obstruction when finished. The probl em is that concrete fram es with flat slabsare not all that easy to build when compared to steel buildings or factory buildings available on the mark et today, andthey are not with out limitations .

Spans are relatively short before beams or th ick deckswith heav y reinforc ement are required. Con struction isslow and labour intensive. Although flat slab formwork ismore efficient than other designs with beams o r voids, therequi rements are still sign ificant. The buildings are heavyand they have a high carbon footprint. Good finishesrequire special effort to control.Semi-precast solutionCobiax Techn ologies and Hanson Building Products havebeen delivering Cobiaxdeck, a semi-precas t so lution withtwo-way void forming that significantly reduces the limitation s of in-situ flat slab construction and introducesadvanced and autom ated construction techniques to traditional concrete structures . The approach has been toremove the critical elements to factory production whi lemaint aining or even improving the sam e structuralintegrity as traditional in-situ flat slab structures.

The semi-precast system with two-way spherical hol

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