Precast Concrete and Factory Production
The corporate goal behind the use of a production method that is to establish itself in the marketplace must be: to produce a product better or cheaper or faster than the competition. So what is the situation with construction using precast concrete elements?
Production in an indoor environment results in better working conditions with correspondingly better productivity than would be the case on a building site, and that has an effect on quality, too.
In the factory production situation, training makes it easier to compensate for the ongoing severe shortage of skilled workers in the construction industry.
Steel moulds can be used for standard elements or large batches, which enables a high degree of dimensional accuracy to be attained.
Factory production enables a specific concrete quality to be achieved. Only through factory production is it possible to produce concrete components with architectural textures and colours, especially for fac¸ade designs. As with other branches of industry outside the construction sector, factory production results in more efficient quality management.
Lower production costs
The main purpose of precast concrete construction is to reduce the cost of the formwork. Several components can be produced in the same formwork, i.e. mould. And of course, large batches are advantageous. Although mould types suited to the method of production (e.g. rigid moulds with few fold-down parts) demand a design approach that suits the production, this does lead to high mould reuses.
Another reason for precast concrete construction was undoubtedly the reduction or total elimination of scaffolding costs.
Factory production enables the use of mechanisation and automation, which in turn can result in a substantial reduction in the number of working hours necessary. However, if a factory’s capacity is not fully exploited, this can be a disadvantage because of the ensuing high proportion of fixed costs.
Material savings arise from the possibility of using thin component cross-sections corresponding to the structural requirements, i.e. double-T or T-sections instead of rectangular sections. The advantage of the (possibly) lower weight of the concrete is in many cases only made possible through the higher quality of the concrete due to the factory production methods. One typical example of saving material and weight is resolving a solid slab into a hollow-core slab. And this is only possible with precast concrete construction.
Prestressing is easy to achieve in the form of pretensioning in the prestressing bed. One considerable cost factor for a precasting factory is of course the cost of transport, which limits the radius of activities and consequently the potential market for a precasting plant and hence its size. This does not represent a hindrance for the precast concrete market as a whole because there are now proficient precasting works within economic reach of any location.
One big advantage of precast concrete construction is the potential to shorten the construction time. For example, wall and suspended floor elements can be produced simultaneously, even while the foundations are still being built. Production, and to a large extent erection as well, can take place during the winter.
No extensive, elaborate on-site facilities are required. The structural carcass is dry and ready for immediate loading immediately after erection.
The financial savings associated with a shorter construction time and the chance of generating revenue at an earlier date are important, often underestimated, reasons for precast concrete construction, particularly for industrial buildings.
However, it should not be forgotten that structures made from precast concrete components often require a higher planning and design input. On the other hand, this input can be substantially reduced by using a standardised precast component system. The first CAD applications in reinforced concrete construction originated in precast concrete