A Guide to Concrete Floor Slab manufacture

Loading & span
No definite type of slab can be seen as the best for a definite application, one will have to think all the factors below and then decide. If more than one floor ideas can be used for the same span, the next factors that might strongly guide you in a direction is the cost of erection and speed of erection.

Cost (Economic considerations of spanning)
In general spans of less than 6m is most economically done with reinforced concrete. When the span is between 6m - 9m, discrete other concrete slab systems can be used and be just as economical or even more economical that reinforced concrete. When the span is more that 9m, general reinforced concrete is not economical anymore and one will have to look at pre-stressed or other special beam systems.

Pre-cast members can also be thought about for economical reasons in large building building for there is a lot of repetition of thorough components and can reduce costs.

Speed of erection
Nowadays speed of building building plays an all the more leading role, especially for the money salvage factor and this has to be looked at intensively when a scheme is started.
Depending on the application, in-situ cast reinforced concrete can be quite economical, but can take longer because of the temporary support required until the concrete has set and is not favorable for large multi-storey buildings. This is best for large residential buildings & small office blocks. With precast members the shuttering is reduced or eliminated totally and thus results in shorter building times and can be very efficient for definite applications but one has to look at the other factors before a decision is made.

Logistics
Post-tensioning instead of pre-tensioned members is recommended where the elements wish excessive transportation because pre-stressed members, is not cast on site and the sizes of the members might have an increase in transportation cost resulting because of the larger vehicle vehicles vital to move them. The accessibility of the definite site also influences this factor, for some larger vehicles may not be capable of accessing the site.

Services
This is especially leading when one makes use of tensioned eg: (pre-stresses or post stressed concrete members) where openings in slab is to be provided one must make sure not to damage the tensioned cables as this may greatly reduce their compel and structural failure might occur. Any services protruding the slab at any point is to be designed beforehand to forestall such failures.