Tissue protects walls against earthquakes

Glass fiber plastic acts as a prophylactic dressing on the building

In long tracks earthquake protection fabric is applied to masonry and then plastered. © M. Urban / KIT
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In earthquakes, usually only seconds remain to escape safely into the open. But falling debris often blocks escape routes from the building. Researchers have now developed a special protective fabric that reinforces the walls and holds back debris. This leaves more time in case of catastrophe to save the inhabitants.

For several years, Lothar Stempniewski and Moritz Urban of the Karlsruhe Institute of Technology (KIT) have been researching how earthquake-prone masonry in existing, older buildings can be subsequently secured at low cost. The result is a fiberglass-plastic fabric with four fiber directions, which can be attached to the house facade with the appropriate plaster. Together with a manufacturer of technical fabrics, they have finally developed the high-tech fabric to production maturity.

Protection against cracks

Due to the very high tensile, stiff glass fiber component of the fabric, which is virtually embedded in the plaster, the masonry can better remove the higher tensile stresses that occur during an earthquake. This prevents punctual damage that grows into cracks. Should the glass fibers nevertheless break during heavy earthquakes, the elastic fibers made of polypropylene will hold the broken wall segments together and thus free escape routes.

Thanks to the reinforcement, the collapse of masonry during earthquakes can be delayed and, ideally, completely prevented. "Especially with short and medium quakes often not much additional tensile strength is needed to prevent the building collapse, " explains Urban. "With the textile building reinforcement we can give the people the necessary time to escape into the open air. Under favorable conditions, the walls even remain intact and the house could be repaired again. "The stabilizing deformation behavior better dissipates the energy that brings the horizontal acceleration forces of an earthquake into the masonry.

Due to the simplicity of the system, which acts as a prophylactic bandage on the building, it can be applied with reasonable effort in the next building renovation combined with thermal insulation. "Even if you strengthen the critical infrastructures such as hospitals, kindergartens, schools or retirement homes, a lot would be achieved in the event of a disaster, " adds Stempniewski. display

In the long term, the team around Stempniewski is researching systems that can be used sensibly not only for brick walls but also for concrete buildings. The challenge of concrete, however, are the greater forces that need to be absorbed. For this we test new materials such as carbon fibers.

(Karlsruhe Institute of Technology, 08.01.2013 - NPO)