It is taken for granted that China’s competitive edge is partly due to its lack of concern for safety at work and for the environment. But building in Shanghai requires 25% prefabrication, replacing traditional methods, and is aiming for 50% in the middle term. Objectives: diminish pollution and reduce work accidents.
In Germany, an old U.S. military base near Frankfurt is to be turned into a top-speed smart city able to accommodate, among other things, some of the refugees that the country has in recent months taken in. Thanks to mass prefabrication, it will be ready in 2019, centenary of the Bauhaus.
In Spain, a company builds complete bathrooms, and these are inserted, sealed, into the building when its structure is finished, to be opened only when the residents are given their keys.
These examples of prefabrication have a common feature: unlike in traditional prefabrication, which was done in the factory but with manual methods, they are based on highly automatized processes.
Seeing how this digitally controlled automatization allows a high degree of flexibility is interesting. It is as efficient in repeating a piece a thousand times as it is in making a thousand different pieces. In this way, the result is totally removed from the monotonous and rigid image we ordinarily associate with prefabrication, which is why there is a preference for the more ambitious term ‘industrialization.’
The process requires that the building – or the parts of it which are to be prepared – be previously molded in a digital medium, from which the computers controlling the robots and the rest of the machinery take orders.
In fact this has already long been going on for certain components of buildings, components which naturally lend themselves to such processes. For example, it has been some time now that irregular metallic structures – like the one of the Guggenheim Museum in Bilbao – are entirely predefined through a computer program, from there passing directly to the program that gives orders to the machine that cuts, mechanizes, and joins bars. The parts already assembled are sent to the construction site, with no limitations but the size of the modes of transport, to be included in the final work.
Components of the more conventional kind, such as enclosures, have taken longer to reach this point, but machinery already exists that is able to execute walls with all the layers and services duly embedded in them, with no need for manual intervention. There are robots that make frames, and GPS-guided machines that simulate the movement of soil on the basis of a model. And there are plans to make huge 3D printers that will raise buildings on site layer by layer.
To make the most of these new systems, the building must be fully defined for execution to even begin, in three dimensions and by digital means, as has been going on in the rest of industry for some time now. This condition is naturally met with when the system used is BIM (Building Information Modeling), which was originally intended to generate the traditional documentation of projects, but has now taken on a more ambitious goal: to go directly from the model created by the designer to the finished building, with no intermediaries interpreting the plans, in the atmosphere of communication between machines that is known as the Internet of Things or Industry 4.0.
For construction to be a ‘normal’ industry, a change of mind-set is required which has already begun, as the examples given here show. Computer technology is not culture, but it provides the infrastructure that is required to support this change.
