How much steel can be saved compared to a ceiling slab solution?

The overall reduction in load depends on the extent of permanent and variable loads, as well as from the lightening ratio of the plate to the full load. This reduction varies between 5 and 15%. On average, steel savings on floors are around 10%. This savings should be added to the reduction of seismic stresses, the reduction in foundation load and the lower stress of vertical structures under static load.

How does the cast occur?

The cast must be in two consecutive steps. The waiting time varies between two and four hours depending on the air temperature. In the first phase, the concrete has to reach the foot of a few centimeters (2-5 cm), thus blocking the formwork. The cast has to be done within the ribs and not directly over the formwork. The second stage is the completion of the jet, and has to occur after a few hours (max 2 hours later, even less when using accelerating grip additives).

How does the connection with the bearing structure work?

NEW NAUTILUS EVO system permits to work both with punctual supports (pillars) and continued ones (beams or bearing walls). In both cases, it is recommended to leave one or more empty bands near the supports, in order to create a full concrete zone capable of bearing the negative moment and/or the punching press that usually occurs in that particular part of the connection. The stress caused by the negative moment and by the punching press can be absorbed by: bent irons nails.

Is it possible to insert expansion and seismic joints?

Nonstandard thickness beam joint                                                                                                                      Key joint

Pin joint

In the realization of seismic joints, the best solution is the creation of a division between the two parts of the buildings, therefore the pilars have to be redoubled. The location and the distance between the two structures is defined by a regulation on the basis of the building height. Moreover, this distance should avoid the hammering effect.

PIlar redoubling

How much do the formworks cost?

The quantity of New Nautilus Evo formworks, in single or double version, depends on the relationship between full zones and lightened zones established at project stage. Medially, it is possible to lighten 75% of the net surface of the slab, with an incidence of trimmings about 1.5-1.75 units per square meter. Concrete, which is saved using lightening, comes to cover up to 100% of the cost of purchasing pallets and the workforce for laying them (depending on local costs). For price information please contact engineering@geoplast.it

Which are the resistance to fire parameters?

Fire resistance, as with traditional structures, depends on the total thickness of the slab, the upper and lower soles and the covering of the reinforcing bars. To attest to the fire resistance of your lightened slab, you can follow the tabular requirements of the national fire resistance standard or perform an analytical thermal calculation by applying a standard temperature curve. The New Nautilus Evo slab can be suitably designed to provide any level of fire protection.

Which are the sound resistance parameters?

At the acoustic level there are two performance parameters to consider. The first is the abatement of air noise, that is, the sound-absorbing power Rw, the second is the transmission of impassive noise, that is the Lnw index. Geoplast is able to provide acoustic performance certifications on request, which put the designers in a position to estimate the acoustic performance of the slab they are going to make.

Which are the maximum loads the system can bear?

The slab sizing depends on many factors: span calculation (distance between two bearing elements), thickness of the applied loads slab (continuous or live), bond conditions (how is the slab linked to the bearing structure). The interweaving of these values leads to innumerable possible solutions. A first indicative idea is provided by the following prediction tables. The Geoplast Technical Department provides free customized prediction with cost analysis after sending the structural tables and the elements needed to calculate the structure. Please contact our service: engineering@geoplast.it

Which type of concrete do I have to use?

The concrete strength class depends on the sizing, however it cannot be lower than C25/30. Its solidity has to be S4 or S5 to guarantee the complete finishing of the lower base even in the case of vibration operations that are done wrong or in the case of cls passage limitations due to high quantities of reinforcement that blocks it. The concrete’s inert maximum size has to be of 32mm. It is possible to use self-levelling concrete and in this case it’s even more important to respect the two pouring stages.

Who cares about the executive floor design?

Normally this is the task of the structural designer responsible for designing the structures of the building, however Geoplast is able to supply this service on request, which will have to be agreed upon when defining the order of supply. For more information, contact engineering@geoplast.it

Can I walk over the formworks?

The formworks are certified to dry walking on them (directly over the plastic even without the mesh), the load tests checks the formwork up to a weight of 150kg to 5x5cm. In the case of a great warmth (>30°C) before walking on them it is recommended to wet the formworks in order to avoid deformations or formworks’ breakages.

Is it possible to drill holes on the slabs?

It is possible to produce all types of holes if they are planned at the design stage. In the design phase, it is necessary to provide reinforcement elements around the holes. For small holes (up to 30x30cm) just remove the form that would go to the hole and insert a pipe (still in the groove) that acts as a formwork. Making holes after building the slab is possible. If the encumbrance is less than the size of the form, it is sufficient to make a drill at the form, otherwise it will be necessary to locally reinforce the slab with chemical anchors reinforced armors and designed to resume the efforts that will develop in the adjacent hole area.

Are the double formworks already assembled when they arrive in the construction site?

NEW NAUTILUS EVO double formworks are not assembled when they arrive in the construction site, in order to take advantage of their stackability.

Does Geoplast rely on third parties for the moulding stage?

Geoplast personally deals with plastic recycling (only partially), moulding, logistics, technical issues and delivery.