Prefabricated concrete systems are the greatest exponent of mechanization in the construction sector. Prefabrication allows the setting of the mortar in optimal conditions and the reduction of the construction time of the building. Using prefabricated concrete structures allows expanding the range of options to create spaces in the Architecture.

Total concrete precast systems

These prefabricated concrete structure systems have the characteristic that they break down the structure into prefabricated parts in the factory using prestressed concrete, and are subsequently assembled on site. Its main advantage lies in the speed of assembly on site. And in the quality of the material, since the pieces are forged in a factory under controlled conditions. They are joined with tongue-and-groove joints and bolts, so work is simplified on site.

Unidirectional structural systems are generally used. Since although there are also bidirectional systems, these are more expensive and more complex. Although in favor of bidirectional systems, it should be noted that they need fewer pillars.

Bidirectional system Unidirectional system

Precast prestressed concrete structures.

In prefabrication, prestressed systems are usually used, which consist of the tensioning of the reinforcement before the application of the concrete. Since when it sets, the reinforcement will tend to recover its original length by introducing axial forces in the piece. This compensates for the tensile stresses when the armature is loaded.

Allowing therefore greater spans in the beams using the same material that would be used in the traditional reinforcement. Prestressing is widely used in precast, since having to set the pieces in a factory can control the process.

Post-tensioned precast concrete systems

Post-tensioned or post-tensioned concrete is called concrete that is subjected, after pouring and setting, to compression forces by means of active reinforcements (steel cables) mounted within sheaths. Unlike prestressed concrete, in which the reinforcements are tensioned before concreting, in post-tensioning the reinforcements are tensioned once the concrete has acquired its characteristic strength.

As in prestressed concrete, the advantage of post-tensioning consists in compressing the concrete before it is put into service, so that the tractions that appear when bending the piece translate into a loss of the previous compression, avoiding more or less As the concrete works in tension, stress for which it is not a suitable material.

Prefabricated concrete structures.

Precast concrete panels allow to build the precast concrete structure without beams or pillars. Following the constructive system of load-bearing walls. They allow to build with great speed, economy and cleanliness by means of tongue-and-groove joints and bolts that join the panels and the forged pieces.

They also improve insulation and allow the facade to be load-bearing. Therefore, buildings are more resistant to torsion and resist earthquakes better.

There are three prefabrication systems with panels:

• The transversal ones, placing the panels in the transversal direction.

• Herringbone, Placing the panels in the longitudinal direction placing parallel transverse panels in the core.

• And the mixed one, which is a mixture of both.

Example of a mixed prefabricated concrete system with a non-bearing façade. In this case, the weight of the floor is distributed on the interior panels, allowing the façade not to support weight.

cellular systems of prefabricated concrete structure.

These systems consist of the decomposition of the building into interchangeable modules supported by an independent structure. In cellular systems, panels lack structural function. One of the most famous examples is the "Nakagin Capsule Center”, Modular building, with 14 levels high and 140 individual capsules, which are used as housing and offices. Work of the Japanese architect Kisho Kurokawa, in the 70s. Each unit (or capsule) was 2.5 × 4m.

The modules must be able to be transported by a large articulated truck. From there, all combinations of transportable pieces are possible, obtaining an almost infinite number of possibilities and sizes of spaces for these homes, both on one floor and in several

Portal structures

The porches are made up of pillars and beams, and they are distributed in parallel to configure the building. They are generally used in unidirectional structures, although they are not exclusive to these. There are arcaded systems with rigid knots and articulated knots.

Pillar anchors