Building safetyNew bracing for durable structures in earthquake-prone regions

Across the world, severe earthquakes regularly shake entire regions. More than two billion people live in danger zones – many of them in structures not built to withstand an earthquake. Together with partners from industry, researchers at the Fraunhofer Institute for Wood Research WKI are developing building materials designed to prevent buildings from collapsing in a natural disaster.

Earthquakes repeatedly claim too many lives, a fact that experts trace back to a lack of preventative measures – particularly when it comes to construction and the failure to comply with standards. All too often, structures in danger areas are not built to withstand an earthquake – a state of affairs that the Center for Light and Environmentally-Friendly Structures of the Fraunhofer Institute for Wood Research, Wilhelm-Klauditz-Institut WKI, is now urgently seeking to address. Fraunhofer says that working together with the Technical University of Braunschweig’s Organic Building Materials and Wood Materials division from the Institute for Building Materials, Concrete Construction and Fire Protection, as well as industry partners such as the company Pitzl Metallbau from Altheim, the researchers are developing solutions for the construction industry that could save thousands of lives. Currently, the engineers at Fraunhofer WKI are working on ultra-durable bracing that will protect even high-rise buildings during an earthquake. The bracing consists of sensor-controlled steel connectors that provide a high level of rigidity while remaining elastic enough to maintain structural integrity in the face of severe shaking. Numerous tests have demonstrated that the connectors work exactly as intended. In one test, the researchers investigated the nature of the stress being placed on structures by applying static, cyclical and dynamic forces; in another, the structure’s service life was tested using environmental simulation. The approach is based on the successful EU SERIES project, which examined earthquake-resistant structures under dynamic loads.

Structures that sway but do not fall
The earthquake-resistant bracing has been designed for buildings with a mullion-and-transom design, and connects the horizontal beams with the vertical post. When exposed to wind or tremors, the connectors must be rigid enough to keep deformation to a minimum – but also elastic enough to withstand strong earthquakes. If deformation does occur, it does not lead to critical stress – in other words, the building sways, but does not collapse.