Part one of this booklet is intended as a quick and general guide to precast concrete floor slabs. In this book we will cover the features and benefits of precast concrete floor slabs, the general applications, some design guidelines, on-site considerations and some general information.
Part two contains the more technical information. For more detailed information specifically regarding design, you are referred to the “Precast concrete floor slabs-design manual” also published by the Concrete Manufacturers Association. Precast slabs can be erected a lot quicker than in situ slabs. Precast slabs can typically be erected in one or two days. The experience and expertise of the precast flooring supplier is readily available to you and they will also prepare designs and drawings for any project undertaken. The supplier will provide you with an engineer’s certificate for submission to the municipality with your plans. economies in the supporting structure and foundations. Very little or no shuttering is required for precast slabs.
Hollow core slabs and beam and block systems incorporating hollow blocks provide superior insulation, although it is recommended that an insulating screed is applied on top of the precast units when they are used as roofs. Precast flooring is more economical than cast in situ concrete, due to the lower mass and better span to depth ratios possible.
These savings in dead weight can lead to further CMA member companies supplying precast floors either have ISO 9002 quality certification or they are busy installing the necessary quality systems. All flooring applications can be executed using precast components, from domestic housing to bridge decks. However, each system has its own specific area of usefulness, where its advantages are best utilized.
For floors in buildings of cellular construction, up to four storeys, if speed and absence of propping are paramount, then hollow core slabs with finished soffits are probably the best choice. For long, uninterrupted spans the prestressed systems are appropriate; beam and block, panel and topping, hollow core. The latter is particularly effective for car parks, hospitals and supermarkets.
For suspended ground floors, where finished soffits are unnecessary, then beam and block is difficult to beat. The panel and topping and beam and block solution is particularly useful if the building is irregular or has multiple cantilevers. Sites where craneage is not possible lend themselves to a beam and block solution, though the narrow hollow core might be possible with short spans. Precast slab systems have a number of advantages over conventional cast in situ concrete.
Table 2 summarises areas where costs are generated on site for a particular item. Naturally the most important cost saving is that of time. The use of precast concrete allows for immediate access to the floor below . In a controlled factory environment, quality checks are not only much easier to do, but also much easier to control, with the result that the product may be expected to be of a more uniform or consistent standard.
Download Precast Concrete Floor Slabs and Concrete Manufacturers Association esaily in PDF format for free.