“The primary concern is saving lives,” Prof. Stempniewski makes clear. “In an emergency, occupants must have enough time to safely leave the earthquake-damaged building before it collapses.” Unstable buildings are one of the greatest dangers in earthquake-prone areas—leaving behind significant structural damage. The extent of this damage depends not only on the magnitude and duration of an earthquake as well as population density, but largely on the seismic safety of the structures themselves. Prof. Stempniewski, head of the the Institute of Concrete Structures and Building Materials (IMB) at KIT, has been conducting research in this field for several years. “As engineers, we take a solution-oriented approach. The problem of earthquakes exists, and we are countering it by aiming to build safer buildings. In my view, however, the solution does not end at the desk, but only when it finds its way to the market,” emphasizes Prof. Stempniewski.

Although the topic has high societal relevance, there are currently few mass-market solutions that offer real stability in those critical seconds. “I only pursue approaches that have been proven to work and for which there is actually a significant market,” explains Stempniewski, continuing: “However, until a technology reaches the market as a product, you have to invest a lot of time and money in research. To develop in the right direction, one has to understand the subject matter at the most fundamental level and combine elements in a targeted way: What is needed? Which material provides the right properties? And how can these be brought together?” These questions ultimately led the reinforced concrete engineers at KIT into unfamiliar territory: working with technical textiles.

High-tech textile with potential

Even before today’s seismic protection system for solid-structure buildings was conceived, the researchers worked on securing inner spaces. A so-called “earthquake wallpaper” was the first project in which Prof. Stempniewski’s research group and the textile experts at Dr. Günther Kast GmbH & Co. KG collaborated. This evolved into a long-standing collaboration that culminated in the licensing of the technology developed at KIT. “It is advantageous to work together in product-oriented research. On the one hand, we as scientists have the opportunity to conduct research close to the market. In return, an industry partner has the chance to add a new product to its portfolio,” says Stempniewski.

Kast, a family-run, medium-sized company based in Sonthofen, Bavaria, specializes in the manufacture of specialty fiber products, such as materials for bookbinders, paper composites, and technical textiles. Managing Director Christoph Kast explains: “We weren’t focused on the earthquake sector, but we were convinced that textiles could make an important contribution to structural reinforcement in solid construction. Licensing as the basis for this is a win-win situation for both sides. The funds benefit the institute, and at the same time, we can ensure that the technology does not remain at a certain stage of development but can be continuously advanced." As a result, the jointly developed EQ-Grid seismic protection system has now become a new pillar of the textile company’s business. Through sublicensing to specialized construction companies, EQ-Grid is already being marketed internationally.

Flexible, Textile Manufacturing

What initially appears quite simple reveals its ingenuity in the details. A major challenge during product development was the demanding textile manufacturing process and finishing. To master the material mix with varying fabric properties, such as melting temperature, the textile specialists at Kast developed a special procedure for manufacturing the distinctive quadraxial textile. A certain degree of strength, necessary for the application and processing of the rolled fabric, was achieved through new finishing processes. Kast explains: “We invested in manufacturing and finishing technology because we want to tap into the niche market of earthquake textiles. This required diligence, as the quality of the materials directly impacts the system’s performance.” It also makes a difference whether 50 meters of a product are manufactured for a test or many times that amount in series production. “Our partner’s textile expertise has contributed significantly to our success. It was only through their processing expertise that we were able to turn our concept into a tangible product,” says scientist Stempniewski.

Smart Textiles for the Future

In Germany, earthquake zones are relatively few and far between and less frequently active. However, there is also a significant need for the system in cases of damage caused by subsidence – for example, when the groundwater recedes and the soil caves in as a result. Therefore, the EQ-Grid system prevents collapse not only in the event of an earthquake. The system demonstrated its stability in scientific experiments during rigorous testing: “No vibrating table in the world has yet managed to break our system,” reports Prof. Stempniewski proudly. “In the future, we will increasingly work with sensors embedded in the fabric to measure quality-relevant values and better assess the condition of masonry,” Prof. Stempniewski looks ahead.