memory-steel to reinforce old buildings

Until now, the steel reinforcements in concrete structures have mostly been prestressed hydraulically. The space requirements for this are immense and this has created the geometric framework conditions for every prestressed concrete structure thus far. It also meant that the strengthening of older structures sometimes failed due to a shortage of space.

Researchers at the Swiss Federal Laboratories for Materials Science and Technology (Empa) have been working on an alternative method for the past 15 years and this is now ready for the market. This involves shape memory alloys based on iron, which contract during heating and therefore permanently prestress the concrete structure. Hydraulic prestressing can now be avoided with this new method. It is sufficient to heat the steel shortly, for example by means of electric current or infrared radiators.

The new building material will be marketed immediately by the Empa spin-off re-fer AG, it was reported in a press release. The company from Ingenbohl will now also be showcasing memory-steel in a series of lectures.

First of all, memory-steel will be used to reinforce existing buildings. The reinforcement of the load-bearing structure is often unavoidable when new windows, doors or lift shafts are installed in the concrete structure of an old building. In future, memory-steel will also be used to “precast concrete parts with a previously unknown geometry”.