Engineers in California have unleashed high-intensity artificial earthquakes on a five-storey building packed with medical equipment. The mock hospital has been built on a giant "shake table" which can subject the building to movements similar to real earthquakes. The tests are designed to determine if hospitals built on rubber bearings could function after a quake. The use of these rubber bearings is common in earthquake-prone Japan. The $5m project also tested whether the bearings could protect other strategically important buildings, such as computer data centers, so they could operate without interruption after a large earthquake. It is the first time that the bearing system has been tested under a full-scale building on a shake table in the United States. "What the bearings do is uncouple the building from the motion of the ground during an earthquake, like putting the building on roller skates," said Tara Hutchinson, an engineering professor at the University of California, San Diego. She said that while most research concentrated on the structural integrity of buildings after an earthquake, very little examined how vital contents such as stairs, lifts and other parts of a building that allowed it to fulfill its function fared after a major seismic event. The building was equipped with a surgery and an intensive-care unit, computer servers and other electrical equipment, as well as stairs and a working lift. The 80ft (24m) structure was also clad in precast concrete and synthetic stucco, two materials which are commonly used in commercial construction projects, and a large water tower and a heating and air-conditioning system was installed on the roof. On the first day of testing in early April, the shake table subjected the building to identical motions to those recorded during the 1994 Northridge earthquake in Los Angeles, which measured 6.7 on the Richter scale, and the 8.8-magnitude Chile earthquake in 2010. The engineers found that the rubber bearings (or "base isolators") successfully protected the building from most of the damaging lateral motion that it would experience during a real earthquake. It also left lifts, stairs, medical equipment and other machinery intact, although there was some minor cosmetic damage. "What we found is that the contents of the building carried on working after our 'earthquakes'," said Professor Hutchinson. "If the equipment had been life-support systems keeping real people alive, then the bearings would have saved their lives." Engineers have now removed the base isolators from beneath the building, and over the next three weeks Professor Hutchinson will repeat the simulated earthquakes so that a direct comparison can be made between the damage to the building's contents with and without them in place. Rubber base isolators have already been retrofitted under the Los Angeles, Oakland and San Francisco city halls.

Scientists at the Karlsruhe Institute of Technology and Bayer have developed a seismic wallpaper that can hold up building walls during earthquakes, reported The Inhabitat. The system, called EQ-Top, is a glass fiber fabric that can help keep mason walls stable. After two years of research and testing, the patented product, which could help keep office buildings and apartments safer during an earthquake, will soon be available for purchase. For many years researchers at the Karlsruhe Institute of Technology (KIT) simulated earthquake scenarios in the quest to find a better way to support buildings in the event of such a disaster. At first they tried using materials with a carbon fiber base, but those created even worse damage after testing. By 2010, the university team began to experiment with glass fibers. These strong and stiff glass fibers are interwoven to create durable and elastic panels. The fibers crisscross in various directions, so they are both strong and pliable, allowing the covering to distribute energy evenly when the walls shake during an earthquake. Standard wallpaper glue is not enough to keep walls standing in the event of seismic activity, however. KIT therefore began working with Bayer's Material Science division to enhance the product. The result was a flexible yet soft adhesive that contains water and polyurethane beads. The adhesive forms to the grooves in a wall's masonry, and as the water evaporates it boosts the wallpaper's strength. The fabric was put to the test in a model home in an earthquake simulator, and thanks to the seismic wallpaper the building still stood and suffered little damage after the simulated quake. Bayer will market the wallpaper later this year. The building material is expected to cost more than regular wallpaper, but builders and homeowners who live in quake-prone areas may find the product well worth the price - and of course - the saved lives.