New technical textiles are being developed for use in civil engineering. These sensor-equipped textiles will help protect architectural structures against natural disasters like earthquakes or landslides.
In the early morning on the 6th of April, 2009, an earthquake of magnitude 5.8 hit the central Italian city of L'Aquila, killing 308 people and destroying the homes of 50,000. Access to the city-centre is restricted to the police, firefighters and civil engineers, while the historical architecture is surveyed to determine how much can be saved. Engineers are hoping that textiles from carbon fibres and glass fibres can be used to stabilise and preserve some of the damaged structures. Both carbon fibre and glass fibre textiles are incredibly thin and flexible and can be fixed to all possible geometries of a structural element.
In some cases, however, textiles alone do not offer enough protection. Engineers near Venice are creating new, multifunctional textiles for the European research project Polytect. These textiles have built-in sensors that could even detect danger before it arrives.
Thomas B. Messervey, a structural engineer for D'Appolonia SpA, explains that the motivational concept is to make an architectural structure more similar to a human body. The fibres provide the structures with a “skin”, a kind of interface between the structure and its environment, using information collected by the sensors. “Structural health modelling” is carried out to evaluate where any structural damage is present, how serious the damage is and its consequences.
Some prototypes already exist. A textile for a masonry structure is made of multidirectional glass fibres to support the multidirectional stresses and loads in the structure. Inside the textiles are fibre-optic cables, through which light is sent to evaluate structural integrity. For protection against landslides geotechnical textiles can be placed underground to strengthen soil or filter water and measure whether the soil is moving. Some textiles contain fibre-optic cables that can be made sensitive to chemicals. These could be used in a landfill to determine whether chemicals are present or to measure the temperature of the landfill.
Laboratory tests, some of which are being conducted at Chemnitz in Germany, have been created to understand the data collected by the sensors in the fabric. In one test, known a the “mushroom test”, it is determined to what extent samples of glass fibres or polypropylene can be deformed before breaking. The sensors will then be able to detect a possible failure of the textile. By these means, the scientists can also learn how the material responds to heavy loads.
Donato Zangani, coordinator of the Polytect project, claims that the main technological challenge is weaving the sensors into the textiles in an efficient manner. The technical requirements are decidedly more ambitious than those in the fashion industry. However, they now have machines capable of weaving textiles with sensors at a speed of 220 metres per hour.
With the implementation of this technology, researchers want that the survivors of earthquakes, like the people of L'Aquila, can feel save again in their homes.