Seismic wallpaper may make the world a little more earthquake resistant !

A high-tech adhesive and glass fiber fabric can make homes safer.

Collapsing ceilings and walls put lives in danger. People in many parts of the world live in constant fear of earthquakes that can reduce entire cities to piles of rubble. Scientists at Bayer MaterialScience, in cooperation with industrial and academic partners, have developed an economical and effective earthquake protection measure in the form of glass fiber fabric combined with a special adhesive which increases the stability of masonry and therefore reduces the risk that apartment and office buildings will turn into deathtraps.
The patent-pending EQ-Top system is as easy to install as wallpaper.

When the earth shakes, every second counts. A strong earthquake turns apartment and office buildings into deathtraps. Pictures from Haiti, Chile, China, New Zealand and Japan illustrate the devastating effects of this natural disaster, with rescue teams searching through ruined buildings and heaps of rubble for survivors.
Buildings collapse in fractions of seconds, like houses of cards. “Even smaller earthquakes can cause dramatic damage, especially to masonry buildings,” explains Professor Lothar Stempniewski, Director of the Institute for Concrete Construction and Construction Materials Technology at the Karlsruhe Institute for Technology (KIT).
The degree of destruction depends less on the severity of the earthquake on the Richter scale than on “how long the structures are shaken by the destructive energy from below the ground,” he says.
Stempniewski has been investigating “earthquake protection for buildings” for many years. Together with experts from Bayer MaterialScience and KAST, a company located in Sonthofen, Bavaria, he has now developed an effective and economical measure that provides added protection against earthquakes. EQ-Top is a special glass fiber fabric “which is simply glued to the wall like wallpaper,” explains Michael Engel, a project manager at Bayer MaterialScience.

“If we can delay the collapse of the masonry or in the best case prevent it altogether, we can save lives,” Stempniewski adds. With his colleagues at the institute, Stempniewski therefore looked for solutions that are effective, economical and easy to install. At the same time, they must provide long lasting protection and give residents those precious extra seconds to escape.

The demand for protection systems of this type is enormous. More than 1.3 billion people worldwide live in earthquake zones. “The starting point for our work was to improve seismic protection in Romania, one of the regions in Europe at greatest risk from earthquakes,” Stempniewski says. In their tests, the KIT scientists identified characteristic fracture behaviors in brick and mortar structures: “Initially they yield at points where stresses are especially high such as the corners of door frames, windows or the mortar between bricks,” according to the KIT scientist. That gave them the idea of covering the walls with a layer of glass fiber fabric to increase the stability of the masonry. “But ordinary wallpaper paste is incapable of transmitting the complex loads from the masonry to the fabric,” explains Dr. Matthias Wintermantel, a Bayer MaterialScience adhesives expert.

In a research alliance with KIT and the fabric specialists from KAST, Wintermantel and his Bayer Material Science team therefore developed the key component for the new EQ-Top system: a special adhesive which firmly anchors the new “seismic wallpaper” to the plaster surface. “We previously tested all conventional adhesives – from simple wallpaper paste to special high performance adhesive. Not one of them was able to meet the tough demand for uniting flexibility and good bonding strength,” said Moritz Urban, a PhD student at the KIT Institute. The test substances were either too weak and detached from the wall or were so brittle that they pulled the plaster right off. It was the work of the Bayer Material-Science scientists which brought about the decisive advance in earthquake protection. Says Stempniewski: “The adhesive is the vital link between the glass fiber and the wall and must therefore adhere equally well to both surfaces.” The flexible special adhesive now used is based on the versatile polyurethane dispersion Dispercoll™ U created by Bayer Material Science. This product is also used to treat the glass fiber fabric, which gives it high tear strength, among other things. Another major benefit of the adhesive is that it is water-based and contains no organic solvents, which means that EQ-Top is ideally suited for indoor use.
“EQ-Top enables us to systematically strengthen the weak points in a wall,” explains Engel. The protective mechanism works like the diagonal braces of a half-timbered house. It distributes the impact energy of the earthquake across the entire wall surface, which thus helps to absorb the energy and prevent points of stress concentration such as door frames and windows from falling under the load. Even if joints crack along the full length of the wall, the glass fiber fabric and adhesive hold the bricks together, which prevents or at least delays the collapse of chunks of masonry and protects the residents.

But the developers had more than just the safety aspect in mind. The protective wallpaper was also designed to be easy to install, unlike systems based was able to meet the tough demand for uniting flexibility and good bonding strength,” said Moritz Urban, a PhD student at the KIT Institute. The test substances were either too weak and detached from the wall or were so brittle that they pulled the plaster right off.
It was the work of the Bayer Material-Science scientists which brought about the decisive advance in earthquake protection. Says Stempniewski: “The adhesive is the vital link between the glass fiber and the wall and must therefore adhere equally well to both surfaces.” The flexible special adhesive now used is based on the versatile polyurethane dispersion Dispercoll™ U created by Bayer Material Science. This product is also used to treat the glass fiber fabric, which gives it high tear strength, among other things.
Another major benefit of the adhesive is that it is water-based and contains no organic solvents, which means that EQ-Top is ideally suited for indoor use.

“EQ-Top enables us to systematically strengthen the weak points in a wall,” explains Engel. The protective mechanism works like the diagonal braces of a half-timbered house. It distributes the impact energy of the earthquake across the entire wall surface, which thus helps to absorb the energy and prevent points of stress concentration such as door frames and windows from falling under the load. Even if joints crack along the full length of the wall, the glass fiber fabric and adhesive hold the bricks together, which prevents or at least delays the collapse of chunks of masonry and protects the residents.

But the developers had more than just the safety aspect in mind. The protective wallpaper was also designed to be easy to install, unlike systems based on carbon fibers, for which the plaster must first be removed, a process that is both very dirty and very expensive.
Carbon-fiber systems can therefore only be used in complex and expensive renovation projects. “EQ-Top can be easily installed by ordinary paperhangers,” Engel says, which generally makes the installation a great deal cheaper.

The intensive development work was worth the effort. EQ-Top was able to prove its worth in numerous tests. The researchers took their system to its limits for the tests. They used huge hydraulic presses to crush one segment of wall after the other – some reinforced by the EQ-Top system and others without it for comparison. The difference was remarkable. The bricks in the protected wall did crumble under very heavy pressure, but the glass fiber fabric and adhesive always held them together. In contrast, the unreinforced wall simply collapsed.

The large-scale tests in which the researchers constructed entire walls with and without doors on a huge shaking table were especially spectacular. The table, built from a thick steel plate, was made to vibrate systematically. The vibrations were transferred to the superstructures – just like during an earthquake when the ground shakes. “We were surprised by the results. Walls reinforced with EQ-Top were virtually impossible to destroy during the tests,” Stempniewski says.

The researchers are convinced that the EQ-Top system could have prevented the worst consequences of Glass fiber fabric prevents buildings from collapsing Further information on the topic of earthquake protection recent earthquakes. “In the New Zealand quake in early 2011, a great many walls crumbled and many houses collapsed completely as a result,” says KIT researcher Moritz Urban. The scientist estimates that the system could have prevented 60 to 70 percent of the damage. “Often it doesn’t take much to prevent the collapse of a building,” Urban says. The scientists are already receiving inquiries about the seismic protection wallpaper from all over the world. The EQ-Top system will soon go on the market, giving people in earthquake zones a few more precious seconds and thereby protecting many of them from the worst consequences of earthquakes.

Text and images : courtesy BAYER, KAST and KIT
http://www.research.bayer.com/seismic-wallpaper